bot update, part 1

Clients/PsnClient/PsnClient.cs

@@ -233,8 +233,11 @@ namespace PsnClient
             }
         }
 
-        public async Task<TitlePatch?> GetTitleUpdatesAsync(string productId, CancellationToken cancellationToken)
+        public async Task<TitlePatch?> GetTitleUpdatesAsync(string? productId, CancellationToken cancellationToken)
         {
+            if (string.IsNullOrEmpty(productId))
+                return null;
+            
             if (ResponseCache.TryGetValue(productId, out TitlePatch patchInfo))
                 return patchInfo;
 

CompatBot/Commands/Attributes/CheckBaseAttributeWithReactions.cs

@@ -10,10 +10,10 @@ namespace CompatBot.Commands.Attributes
     {
         protected abstract Task<bool> IsAllowed(CommandContext ctx, bool help);
 
-        public DiscordEmoji ReactOnSuccess { get; }
-        public DiscordEmoji ReactOnFailure { get; }
+        public DiscordEmoji? ReactOnSuccess { get; }
+        public DiscordEmoji? ReactOnFailure { get; }
 
-        public CheckBaseAttributeWithReactions(DiscordEmoji reactOnSuccess = null, DiscordEmoji reactOnFailure = null)
+        public CheckBaseAttributeWithReactions(DiscordEmoji? reactOnSuccess = null, DiscordEmoji? reactOnFailure = null)
         {
             ReactOnSuccess = reactOnSuccess;
             ReactOnFailure = reactOnFailure;

CompatBot/Commands/BotStats.cs

@@ -80,7 +80,7 @@ namespace CompatBot.Commands
                 var timestamps = db.Warning
                     .Where(w => w.Timestamp.HasValue && !w.Retracted)
                     .OrderBy(w => w.Timestamp)
-                    .Select(w => w.Timestamp.Value)
+                    .Select(w => w.Timestamp!.Value)
                     .ToList();
                 var firstWarnTimestamp = timestamps.FirstOrDefault();
                 var previousTimestamp = firstWarnTimestamp;
@@ -122,7 +122,7 @@ namespace CompatBot.Commands
                 if (warnCount > mostWarnings)
                 {
                     mostWarnings = warnCount;
-                    mostWarningsStart = last24hWarnings.Min(w => w.Timestamp.Value);
+                    mostWarningsStart = last24hWarnings.Min(w => w.Timestamp!.Value);
                     mostWarningsEnd = utcNow.Ticks;
                 }
                 var lastWarn = timestamps.Any() ? timestamps.Last() : (long?)null;
@@ -150,7 +150,7 @@ namespace CompatBot.Commands
                 {
                     statsBuilder.Append($"Warnings in the last 24h: **{warnCount}**");
                     if (warnCount == 0)
-                        statsBuilder.Append(" ").Append(BotReactionsHandler.RandomPositiveReaction);
+                        statsBuilder.Append(' ').Append(BotReactionsHandler.RandomPositiveReaction);
                     statsBuilder.AppendLine();
                 }
                 if (lastWarn.HasValue)
@@ -173,15 +173,15 @@ namespace CompatBot.Commands
                 .ToList();
             var totalCalls = sortedCommandStats.Sum(c => c.stat);
             var top = sortedCommandStats.Take(5).ToList();
-            if (top.Any())
-            {
-                var statsBuilder = new StringBuilder();
-                var n = 1;
-                foreach (var cmdStat in top)
-                    statsBuilder.AppendLine($"{n++}. {cmdStat.name} ({cmdStat.stat} call{(cmdStat.stat == 1 ? "" : "s")}, {cmdStat.stat * 100.0 / totalCalls:0.##}%)");
-                statsBuilder.AppendLine($"Total commands executed: {totalCalls}");
-                embed.AddField($"Top {top.Count} Recent Commands", statsBuilder.ToString().TrimEnd(), true);
-            }
+            if (top.Count == 0)
+                return;
+            
+            var statsBuilder = new StringBuilder();
+            var n = 1;
+            foreach (var (name, stat) in top)
+                statsBuilder.AppendLine($"{n++}. {name} ({stat} call{(stat == 1 ? "" : "s")}, {stat * 100.0 / totalCalls:0.##}%)");
+            statsBuilder.AppendLine($"Total commands executed: {totalCalls}");
+            embed.AddField($"Top {top.Count} Recent Commands", statsBuilder.ToString().TrimEnd(), true);
         }
 
         private static void AppendExplainStats(DiscordEmbedBuilder embed)
@@ -194,15 +194,15 @@ namespace CompatBot.Commands
                 .ToList();
             var totalExplains = sortedTerms.Sum(t => t.stat);
             var top = sortedTerms.Take(5).ToList();
-            if (top.Any())
-            {
-                var statsBuilder = new StringBuilder();
-                var n = 1;
-                foreach (var explain in top)
-                    statsBuilder.AppendLine($"{n++}. {explain.term} ({explain.stat} display{(explain.stat == 1 ? "" : "s")}, {explain.stat * 100.0 / totalExplains:0.##}%)");
-                statsBuilder.AppendLine($"Total explanations shown: {totalExplains}");
-                embed.AddField($"Top {top.Count} Recent Explanations", statsBuilder.ToString().TrimEnd(), true);
-            }
+            if (top.Count == 0)
+                return;
+            
+            var statsBuilder = new StringBuilder();
+            var n = 1;
+            foreach (var (term, stat) in top)
+                statsBuilder.AppendLine($"{n++}. {term} ({stat} display{(stat == 1 ? "" : "s")}, {stat * 100.0 / totalExplains:0.##}%)");
+            statsBuilder.AppendLine($"Total explanations shown: {totalExplains}");
+            embed.AddField($"Top {top.Count} Recent Explanations", statsBuilder.ToString().TrimEnd(), true);
         }
 
         private static void AppendGameLookupStats(DiscordEmbedBuilder embed)
@@ -215,15 +215,15 @@ namespace CompatBot.Commands
                 .ToList();
             var totalLookups = sortedTitles.Sum(t => t.stat);
             var top = sortedTitles.Take(5).ToList();
-            if (top.Any())
-            {
-                var statsBuilder = new StringBuilder();
-                var n = 1;
-                foreach (var title in top)
-                    statsBuilder.AppendLine($"{n++}. {title.title.Trim(40)} ({title.stat} search{(title.stat == 1 ? "" : "es")}, {title.stat * 100.0 / totalLookups:0.##}%)");
-                statsBuilder.AppendLine($"Total game lookups: {totalLookups}");
-                embed.AddField($"Top {top.Count} Recent Game Lookups", statsBuilder.ToString().TrimEnd(), true);
-            }
+            if (top.Count == 0)
+                return;
+            
+            var statsBuilder = new StringBuilder();
+            var n = 1;
+            foreach (var (title, stat) in top)
+                statsBuilder.AppendLine($"{n++}. {title.Trim(40)} ({stat} search{(stat == 1 ? "" : "es")}, {stat * 100.0 / totalLookups:0.##}%)");
+            statsBuilder.AppendLine($"Total game lookups: {totalLookups}");
+            embed.AddField($"Top {top.Count} Recent Game Lookups", statsBuilder.ToString().TrimEnd(), true);
         }
 
         private void AppendSyscallsStats(DiscordEmbedBuilder embed)
@@ -259,7 +259,12 @@ namespace CompatBot.Commands
 
                 var diff = kots > doggos ? (double)kots / doggos - 1.0 : (double)doggos / kots - 1.0;
                 var sign = double.IsNaN(diff) || (double.IsFinite(diff) && !double.IsNegative(diff) && diff < 0.05) ? ":" : (kots > doggos ? ">" : "<");
-                var kot = sign == ">" ? GoodKot[new Random().Next(GoodKot.Length)] : sign == ":" ? "🐱" : MeanKot[new Random().Next(MeanKot.Length)];
+                var kot = sign switch
+                {
+                    ">" => GoodKot[new Random().Next(GoodKot.Length)],
+                    ":" => "🐱",
+                    _ => MeanKot[new Random().Next(MeanKot.Length)]
+                };
                 embed.AddField("🐾 Stats", $"{kot} {kots - 1} {sign} {doggos - 1} 🐶", true);
             }
             catch (Exception e)

CompatBot/Commands/CommandsManagement.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
@@ -32,8 +33,9 @@ namespace CompatBot.Commands
 
         [Command("disable"), Aliases("add")]
         [Description("Disables the specified command")]
-        public async Task Disable(CommandContext ctx, [RemainingText, Description("Fully qualified command to disable, e.g. `explain add` or `sudo mod *`")] string command)
+        public async Task Disable(CommandContext ctx, [RemainingText, Description("Fully qualified command to disable, e.g. `explain add` or `sudo mod *`")] string? command)
         {
+            command ??= "";
             var isPrefix = command.EndsWith('*');
             if (isPrefix)
                 command = command.TrimEnd('*', ' ');
@@ -94,7 +96,7 @@ namespace CompatBot.Commands
 
         [Command("enable"), Aliases("reenable", "remove", "delete", "del", "clear")]
         [Description("Enables the specified command")]
-        public async Task Enable(CommandContext ctx, [RemainingText, Description("Fully qualified command to enable, e.g. `explain add` or `sudo mod *`")] string command)
+        public async Task Enable(CommandContext ctx, [RemainingText, Description("Fully qualified command to enable, e.g. `explain add` or `sudo mod *`")] string? command)
         {
             if (command == "*")
             {
@@ -103,6 +105,7 @@ namespace CompatBot.Commands
                 return;
             }
 
+            command ??= "";
             var isPrefix = command.EndsWith('*');
             if (isPrefix)
                 command = command.TrimEnd('*', ' ');
@@ -148,13 +151,13 @@ namespace CompatBot.Commands
             }
         }
 
-        private static Command GetCommand(CommandContext ctx, string qualifiedName)
+        private static Command? GetCommand(CommandContext ctx, string qualifiedName)
         {
             if (string.IsNullOrEmpty(qualifiedName))
                 return null;
 
-            var groups = ctx.CommandsNext.RegisteredCommands.Values;
-            Command result = null;
+            var groups = (IReadOnlyList<Command>)ctx.CommandsNext.RegisteredCommands.Values.ToList();
+            Command? result = null;
             foreach (var cmdPart in qualifiedName.Split(' ', StringSplitOptions.RemoveEmptyEntries))
             {
                 if (groups.FirstOrDefault(g => g.Name == cmdPart || g.Aliases.Any(a => a == cmdPart)) is Command c)

CompatBot/Commands/CompatList.cs

@@ -6,6 +6,7 @@ using System.IO;
 using System.Linq;
 using System.Net.Http;
 using System.Text;
+using System.Text.Json;
 using System.Text.RegularExpressions;
 using System.Threading;
 using System.Threading.Tasks;
@@ -28,7 +29,6 @@ using DSharpPlus.Interactivity.Extensions;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Caching.Memory;
 using Microsoft.TeamFoundation.Build.WebApi;
-using Newtonsoft.Json;
 
 namespace CompatBot.Commands
 {
@@ -37,10 +37,10 @@ namespace CompatBot.Commands
         private static readonly Client client = new Client();
         private static readonly GithubClient.Client githubClient = new GithubClient.Client();
         private static readonly SemaphoreSlim updateCheck = new SemaphoreSlim(1, 1);
-        private static string lastUpdateInfo = null, lastFullBuildNumber = null;
+        private static string? lastUpdateInfo = null, lastFullBuildNumber = null;
         private const string Rpcs3UpdateStateKey = "Rpcs3UpdateState";
         private const string Rpcs3UpdateBuildKey = "Rpcs3UpdateBuild";
-        private static UpdateInfo CachedUpdateInfo = null;
+        private static UpdateInfo? CachedUpdateInfo = null;
         private static readonly Regex UpdateVersionRegex = new Regex(@"v(?<version>\d+\.\d+\.\d+)-(?<build>\d+)-(?<commit>[0-9a-f]+)\b", RegexOptions.Compiled | RegexOptions.Singleline | RegexOptions.ExplicitCapture);
 
         static CompatList()
@@ -68,7 +68,7 @@ namespace CompatBot.Commands
 
         [Command("compat"), Aliases("c", "compatibility")]
         [Description("Searches the compatibility database, USE: !compat search term")]
-        public async Task Compat(CommandContext ctx, [RemainingText, Description("Game title to look up")] string title)
+        public async Task Compat(CommandContext ctx, [RemainingText, Description("Game title to look up")] string? title)
         {
             title = title?.TrimEager().Truncate(40);
             if (string.IsNullOrEmpty(title))
@@ -122,13 +122,13 @@ namespace CompatBot.Commands
             scoreType = scoreType.ToLowerInvariant();
 
             number = number.Clamp(1, 100);
-            bool exactStatus = status.EndsWith("only");
+            var exactStatus = status.EndsWith("only");
             if (exactStatus)
                 status = status[..^4];
             if (!Enum.TryParse(status, true, out CompatStatus s))
                 s = CompatStatus.Playable;
 
-            using var db = new ThumbnailDb();
+            await using var db = new ThumbnailDb();
             var queryBase = db.Thumbnail.AsNoTracking();
             if (exactStatus)
                 queryBase = queryBase.Where(g => g.CompatibilityStatus == s);
@@ -137,9 +137,9 @@ namespace CompatBot.Commands
             queryBase = queryBase.Where(g => g.Metacritic != null).Include(t => t.Metacritic);
             var query = scoreType switch
             {
-                "critic" => queryBase.Where(t => t.Metacritic.CriticScore > 0).AsEnumerable().Select(t => (title: t.Metacritic.Title, score: t.Metacritic.CriticScore.Value, second: t.Metacritic.UserScore ?? t.Metacritic.CriticScore.Value)),
-                "user" => queryBase.Where(t => t.Metacritic.UserScore > 0).AsEnumerable().Select(t => (title: t.Metacritic.Title, score: t.Metacritic.UserScore.Value, second: t.Metacritic.CriticScore ?? t.Metacritic.UserScore.Value)),
-                _ => queryBase.AsEnumerable().Select(t => (title: t.Metacritic.Title, score: Math.Max(t.Metacritic.CriticScore ?? 0, t.Metacritic.UserScore ?? 0), second: (byte)0)),
+                "critic" => queryBase.Where(t => t.Metacritic!.CriticScore > 0).AsEnumerable().Select(t => (title: t.Metacritic!.Title, score: t.Metacritic!.CriticScore!.Value, second: t.Metacritic.UserScore ?? t.Metacritic.CriticScore.Value)),
+                "user" => queryBase.Where(t => t.Metacritic!.UserScore > 0).AsEnumerable().Select(t => (title: t.Metacritic!.Title, score: t.Metacritic!.UserScore!.Value, second: t.Metacritic.CriticScore ?? t.Metacritic.UserScore.Value)),
+                _ => queryBase.AsEnumerable().Select(t => (title: t.Metacritic!.Title, score: Math.Max(t.Metacritic.CriticScore ?? 0, t.Metacritic.UserScore ?? 0), second: (byte)0)),
             };
             var resultList = query.Where(i => i.score > 0)
                 .OrderByDescending(i => i.score)
@@ -161,7 +161,7 @@ namespace CompatBot.Commands
                 await ctx.SendAutosplitMessageAsync(result, blockStart: null, blockEnd: null).ConfigureAwait(false);
             }
             else
-                await ctx.RespondAsync("Failed to generate lilst").ConfigureAwait(false);
+                await ctx.RespondAsync("Failed to generate list").ConfigureAwait(false);
         }
 
         [Group("latest"), TriggersTyping]
@@ -200,7 +200,7 @@ namespace CompatBot.Commands
                 return CheckForRpcs3Updates(ctx.Client, null);
             }
 
-            public static async Task<bool> CheckForRpcs3Updates(DiscordClient discordClient, DiscordChannel channel, string sinceCommit = null, DiscordMessage emptyBotMsg = null)
+            public static async Task<bool> CheckForRpcs3Updates(DiscordClient discordClient, DiscordChannel? channel, string? sinceCommit = null, DiscordMessage? emptyBotMsg = null)
             {
                 var updateAnnouncement = channel is null;
                 var updateAnnouncementRestore = emptyBotMsg != null;
@@ -215,7 +215,7 @@ namespace CompatBot.Commands
                 {
                     if (updateAnnouncementRestore)
                     {
-                        Config.Log.Debug($"Failed to get update info for commit {sinceCommit}: {JsonConvert.SerializeObject(info)}");
+                        Config.Log.Debug($"Failed to get update info for commit {sinceCommit}: {JsonSerializer.Serialize(info)}");
                         return false;
                     }
 
@@ -232,7 +232,7 @@ namespace CompatBot.Commands
                 }
                 if (!updateAnnouncement)
                 {
-                    await channel.SendMessageAsync(embed: embed.Build()).ConfigureAwait(false);
+                    await channel!.SendMessageAsync(embed: embed.Build()).ConfigureAwait(false);
                     return true;
                 }
                 if (updateAnnouncementRestore)
@@ -241,7 +241,7 @@ namespace CompatBot.Commands
                         return false;
 
                     Config.Log.Debug($"Restoring update announcement for build {sinceCommit}: {embed.Title}\n{embed.Description}");
-                    await emptyBotMsg.ModifyAsync(embed: embed.Build()).ConfigureAwait(false);
+                    await emptyBotMsg!.ModifyAsync(embed: embed.Build()).ConfigureAwait(false);
                     return true;
                 }
 
@@ -287,15 +287,15 @@ namespace CompatBot.Commands
                     await compatChannel.SendMessageAsync(embed: embed.Build()).ConfigureAwait(false);
                     lastUpdateInfo = latestUpdatePr;
                     lastFullBuildNumber = latestUpdateBuild;
-                    using var db = new BotDb();
+                    await using var db = new BotDb();
                     var currentState = await db.BotState.FirstOrDefaultAsync(k => k.Key == Rpcs3UpdateStateKey).ConfigureAwait(false);
                     if (currentState == null)
-                        db.BotState.Add(new BotState {Key = Rpcs3UpdateStateKey, Value = latestUpdatePr});
+                        await db.BotState.AddAsync(new BotState {Key = Rpcs3UpdateStateKey, Value = latestUpdatePr}).ConfigureAwait(false);
                     else
                         currentState.Value = latestUpdatePr;
                     var savedLastBuild = await db.BotState.FirstOrDefaultAsync(k => k.Key == Rpcs3UpdateBuildKey).ConfigureAwait(false);
                     if (savedLastBuild == null)
-                        db.BotState.Add(new BotState {Key = Rpcs3UpdateBuildKey, Value = latestUpdateBuild});
+                        await db.BotState.AddAsync(new BotState {Key = Rpcs3UpdateBuildKey, Value = latestUpdateBuild}).ConfigureAwait(false);
                     else
                         savedLastBuild.Value = latestUpdateBuild;
                     await db.SaveChangesAsync(Config.Cts.Token).ConfigureAwait(false);
@@ -313,7 +313,7 @@ namespace CompatBot.Commands
                 return false;
             }
 
-            private static async Task CheckMissedBuildsBetween(DiscordClient discordClient, DiscordChannel compatChannel, string previousUpdatePr, string latestUpdatePr, CancellationToken cancellationToken)
+            private static async Task CheckMissedBuildsBetween(DiscordClient discordClient, DiscordChannel compatChannel, string? previousUpdatePr, string? latestUpdatePr, CancellationToken cancellationToken)
             {
                 if (!int.TryParse(previousUpdatePr, out var oldestPr)
                     || !int.TryParse(latestUpdatePr, out var newestPr))
@@ -322,16 +322,16 @@ namespace CompatBot.Commands
                 var mergedPrs = await githubClient.GetClosedPrsAsync(cancellationToken).ConfigureAwait(false); // this will cache 30 latest PRs
                 var newestPrCommit = await githubClient.GetPrInfoAsync(newestPr, cancellationToken).ConfigureAwait(false);
                 var oldestPrCommit = await githubClient.GetPrInfoAsync(oldestPr, cancellationToken).ConfigureAwait(false);
-                if (newestPrCommit.MergedAt == null || oldestPrCommit.MergedAt == null)
+                if (newestPrCommit?.MergedAt == null || oldestPrCommit?.MergedAt == null)
                     return;
 
                 mergedPrs = mergedPrs?.Where(pri => pri.MergedAt.HasValue)
-                    .OrderBy(pri => pri.MergedAt.Value)
+                    .OrderBy(pri => pri.MergedAt!.Value)
                     .SkipWhile(pri => pri.Number != oldestPr)
                     .Skip(1)
                     .TakeWhile(pri => pri.Number != newestPr)
                     .ToList();
-                if (mergedPrs is null || mergedPrs.Count == 0)
+                if (mergedPrs is null or {Count: 0})
                     return;
 
                 var failedBuilds = await Config.GetAzureDevOpsClient().GetMasterBuildsAsync(
@@ -353,7 +353,7 @@ namespace CompatBot.Commands
                     }
                     else if (updateInfo.ReturnCode == -1) // unknown build
                     {
-                        var masterBuildInfo = failedBuilds.FirstOrDefault(b => b.Commit.Equals(mergedPr.MergeCommitSha, StringComparison.InvariantCultureIgnoreCase));
+                        var masterBuildInfo = failedBuilds?.FirstOrDefault(b => b.Commit?.Equals(mergedPr.MergeCommitSha, StringComparison.InvariantCultureIgnoreCase) is true);
                         var buildTime = masterBuildInfo?.FinishTime;
                         if (masterBuildInfo != null)
                         {
@@ -406,14 +406,14 @@ namespace CompatBot.Commands
         private async Task DoRequestAndRespond(CommandContext ctx, RequestBuilder requestBuilder)
         {
             Config.Log.Info(requestBuilder.Build());
-            CompatResult result = null;
+            CompatResult? result = null;
             try
             {
                 var remoteSearchTask = client.GetCompatResultAsync(requestBuilder, Config.Cts.Token);
                 var localResult = GetLocalCompatResult(requestBuilder);
                 result = localResult;
                 var remoteResult = await remoteSearchTask.ConfigureAwait(false);
-                result = remoteResult.Append(localResult);
+                result = remoteResult?.Append(localResult);
             }
             catch
             {
@@ -428,9 +428,9 @@ namespace CompatBot.Commands
             await Task.Delay(5_000).ConfigureAwait(false);
 #endif
             var channel = await ctx.GetChannelForSpamAsync().ConfigureAwait(false);
-            if (result.Results?.Count == 1)
+            if (result?.Results?.Count == 1)
                 await ProductCodeLookup.LookupAndPostProductCodeEmbedAsync(ctx.Client, ctx.Message, new List<string>(result.Results.Keys)).ConfigureAwait(false);
-            else
+            else if (result != null)
                 foreach (var msg in FormatSearchResults(ctx, result))
                     await channel.SendAutosplitMessageAsync(msg, blockStart: "", blockEnd: "").ConfigureAwait(false);
         }
@@ -475,15 +475,15 @@ namespace CompatBot.Commands
             {
                 var authorMention = ctx.Channel.IsPrivate ? "You" : ctx.Message.Author.Mention;
                 var result = new StringBuilder();
-                result.AppendLine($"{authorMention} searched for: ***{request.Search.Sanitize(replaceBackTicks: true)}***");
-                if (request.Search.Contains("persona", StringComparison.InvariantCultureIgnoreCase)
-                    || request.Search.Contains("p5", StringComparison.InvariantCultureIgnoreCase))
+                result.AppendLine($"{authorMention} searched for: ***{request.Search?.Sanitize(replaceBackTicks: true)}***");
+                if (request.Search?.Contains("persona", StringComparison.InvariantCultureIgnoreCase) is true
+                    || request.Search?.Contains("p5", StringComparison.InvariantCultureIgnoreCase) is true)
                     result.AppendLine("Did you try searching for **__Unnamed__** instead?");
                 else if (!ctx.Channel.IsPrivate
                          && ctx.Message.Author.Id == 197163728867688448
-                         && (compatResult.Results.Values.Any(i =>
+                         && compatResult.Results.Values.Any(i =>
                              i.Title.Contains("afrika", StringComparison.InvariantCultureIgnoreCase)
-                             || i.Title.Contains("africa", StringComparison.InvariantCultureIgnoreCase)))
+                             || i.Title.Contains("africa", StringComparison.InvariantCultureIgnoreCase))
                 )
                 {
                     var sqvat = ctx.Client.GetEmoji(":sqvat:", Config.Reactions.No);
@@ -543,27 +543,34 @@ namespace CompatBot.Commands
         public static async Task ImportCompatListAsync()
         {
             var list = await client.GetCompatListSnapshotAsync(Config.Cts.Token).ConfigureAwait(false);
-            using var db = new ThumbnailDb();
+            if (list is null)
+                return;
+            
+            await using var db = new ThumbnailDb();
             foreach (var kvp in list.Results)
             {
                 var (productCode, info) = kvp;
                 var dbItem = await db.Thumbnail.FirstOrDefaultAsync(t => t.ProductCode == productCode).ConfigureAwait(false);
-                if (dbItem == null)
+                if (dbItem is null
+                    && await client.GetCompatResultAsync(RequestBuilder.Start().SetSearch(productCode), Config.Cts.Token).ConfigureAwait(false) is {} compatItemSearchResult
+                    && compatItemSearchResult.Results.TryGetValue(productCode, out var compatItem))
                 {
-                    var compatItemSearchResult = await client.GetCompatResultAsync(RequestBuilder.Start().SetSearch(productCode), Config.Cts.Token).ConfigureAwait(false);
-                    if (compatItemSearchResult.Results.TryGetValue(productCode, out var compatItem))
-                        dbItem = db.Thumbnail.Add(new Thumbnail
-                        {
-                            ProductCode = productCode,
-                            Name = compatItem.Title,
-                        }).Entity;
+                    dbItem = (await db.Thumbnail.AddAsync(new Thumbnail
+                    {
+                        ProductCode = productCode,
+                        Name = compatItem.Title,
+                    }).ConfigureAwait(false)).Entity;
                 }
-                if (dbItem == null)
+                if (dbItem is null)
+                {
                     Config.Log.Debug($"Missing product code {productCode} in {nameof(ThumbnailDb)}");
+                    dbItem = new();
+                }
                 if (Enum.TryParse(info.Status, out CompatStatus status))
                 {
                     dbItem.CompatibilityStatus = status;
-                    if (info.Date is string d && DateTime.TryParseExact(d, "yyyy-MM-dd", CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal, out var date))
+                    if (info.Date is string d
+                        && DateTime.TryParseExact(d, "yyyy-MM-dd", CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal, out var date))
                         dbItem.CompatibilityChangeDate = date.Ticks;
                 }
                 else
@@ -577,7 +584,7 @@ namespace CompatBot.Commands
             var scoreJson = "metacritic_ps3.json";
             string json;
             if (File.Exists(scoreJson))
-                json = File.ReadAllText(scoreJson);
+                json = await File.ReadAllTextAsync(scoreJson).ConfigureAwait(false);
             else
             {
                 Config.Log.Warn($"Missing {scoreJson}, trying to get an online copy...");
@@ -593,7 +600,8 @@ namespace CompatBot.Commands
                 }
             }
 
-            var scoreList = JsonConvert.DeserializeObject<List<Metacritic>>(json);
+            var scoreList = JsonSerializer.Deserialize<List<Metacritic>>(json) ?? new();
+            
             Config.Log.Debug($"Importing {scoreList.Count} Metacritic items");
             var duplicates = new List<Metacritic>();
             duplicates.AddRange(
@@ -602,7 +610,7 @@ namespace CompatBot.Commands
             );
             duplicates.AddRange(
                 scoreList.Where(i => i.Title.Contains("A Telltale Game"))
-                    .Select(i => i.WithTitle(i.Title.Substring(0, i.Title.IndexOf("A Telltale Game") - 1).TrimEnd(' ', '-', ':')))
+                    .Select(i => i.WithTitle(i.Title.Substring(0, i.Title.IndexOf("A Telltale Game", StringComparison.Ordinal) - 1).TrimEnd(' ', '-', ':')))
             );
             duplicates.AddRange(
                 scoreList.Where(i => i.Title.StartsWith("Ratchet & Clank Future"))
@@ -617,7 +625,7 @@ namespace CompatBot.Commands
                     .Select(i => i.WithTitle(i.Title.Replace("HAWX", "H.A.W.X")))
                 );
 
-            using var db = new ThumbnailDb();
+            await using var db = new ThumbnailDb();
             foreach (var mcScore in scoreList.Where(s => s.CriticScore > 0 || s.UserScore > 0))
             {
                 if (Config.Cts.IsCancellationRequested)
@@ -625,7 +633,7 @@ namespace CompatBot.Commands
 
                 var item = db.Metacritic.FirstOrDefault(i => i.Title == mcScore.Title);
                 if (item == null)
-                    item = db.Metacritic.Add(mcScore).Entity;
+                    item = (await db.Metacritic.AddAsync(mcScore).ConfigureAwait(false)).Entity;
                 else
                 {
                     item.CriticScore = mcScore.CriticScore;
@@ -656,11 +664,12 @@ namespace CompatBot.Commands
                     try
                     {
                         var searchResult = await client.GetCompatResultAsync(RequestBuilder.Start().SetSearch(title), Config.Cts.Token).ConfigureAwait(false);
-                        var compatListMatches = searchResult.Results
+                        var compatListMatches = searchResult?.Results
                             .Select(i => (productCode: i.Key, titleInfo: i.Value, coef: Math.Max(title.GetFuzzyCoefficientCached(i.Value.Title), title.GetFuzzyCoefficientCached(i.Value.AlternativeTitle))))
                             .Where(i => i.coef > 0.85)
                             .OrderByDescending(i => i.coef)
-                            .ToList();
+                            .ToList()
+                            ?? new();
                         if (compatListMatches.Any(i => i.coef > 0.99))
                             compatListMatches = compatListMatches.Where(i => i.coef > 0.99).ToList();
                         else if (compatListMatches.Any(i => i.coef > 0.95))
@@ -670,21 +679,21 @@ namespace CompatBot.Commands
                         foreach ((string productCode, TitleInfo titleInfo, double coef) in compatListMatches)
                         {
                             var dbItem = await db.Thumbnail.FirstOrDefaultAsync(i => i.ProductCode == productCode).ConfigureAwait(false);
-                            if (dbItem == null)
-                                dbItem = db.Thumbnail.Add(new Thumbnail
+                            if (dbItem is null)
+                                dbItem = (await db.Thumbnail.AddAsync(new Thumbnail
                                 {
                                     ProductCode = productCode,
                                     Name = titleInfo.Title,
-                                }).Entity;
-                            if (dbItem != null)
-                            {
-                                dbItem.Name = titleInfo.Title;
-                                if (Enum.TryParse(titleInfo.Status, out CompatStatus status))
-                                    dbItem.CompatibilityStatus = status;
-                                if (DateTime.TryParseExact(titleInfo.Date, "yyyy-MM-dd", CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal, out var date))
-                                    dbItem.CompatibilityChangeDate = date.Ticks;
-                                matches.Add((dbItem, coef));
-                            }
+                                }).ConfigureAwait(false)).Entity;
+                            if (dbItem is null)
+                                continue;
+                            
+                            dbItem.Name = titleInfo.Title;
+                            if (Enum.TryParse(titleInfo.Status, out CompatStatus status))
+                                dbItem.CompatibilityStatus = status;
+                            if (DateTime.TryParseExact(titleInfo.Date, "yyyy-MM-dd", CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal, out var date))
+                                dbItem.CompatibilityChangeDate = date.Ticks;
+                            matches.Add((dbItem, coef));
                         }
                         await db.SaveChangesAsync().ConfigureAwait(false);
                     }
@@ -693,7 +702,7 @@ namespace CompatBot.Commands
                         Config.Log.Warn(e);
                     }
                 }
-                matches = matches.Where(i => !Regex.IsMatch(i.thumb.Name, @"\b(demo|trial)\b", RegexOptions.IgnoreCase | RegexOptions.Singleline)).ToList();
+                matches = matches.Where(i => !Regex.IsMatch(i.thumb.Name ?? "", @"\b(demo|trial)\b", RegexOptions.IgnoreCase | RegexOptions.Singleline)).ToList();
                 //var bestMatch = matches.FirstOrDefault();
                 //Config.Log.Trace($"Best title match for [{item.Title}] is [{bestMatch.thumb.Name}] with score {bestMatch.coef:0.0000}");
                 if (matches.Count > 0)

CompatBot/Commands/ContentFilters.cs

@@ -39,47 +39,45 @@ namespace CompatBot.Commands
                 new AsciiColumn("Actions"),
                 new AsciiColumn("Custom message")
             );
-            using (var db = new BotDb())
+            await using var db = new BotDb();
+            var duplicates = new Dictionary<string, FilterContext>(StringComparer.InvariantCultureIgnoreCase);
+            var filters = db.Piracystring.Where(ps => !ps.Disabled).AsNoTracking().AsEnumerable().OrderBy(ps => ps.String.ToUpperInvariant()).ToList();
+            var nonUniqueTriggers = (
+                from f in filters
+                group f by f.String.ToUpperInvariant()
+                into g
+                where g.Count() > 1
+                select g.Key
+            ).ToList();
+            foreach (var t in nonUniqueTriggers)
             {
-                var duplicates = new Dictionary<string, FilterContext>(StringComparer.InvariantCultureIgnoreCase);
-                var filters = db.Piracystring.Where(ps => !ps.Disabled).AsNoTracking().AsEnumerable().OrderBy(ps => ps.String.ToUpperInvariant()).ToList();
-                var nonUniqueTriggers = (
-                    from f in filters
-                    group f by f.String.ToUpperInvariant()
-                    into g
-                    where g.Count() > 1
-                    select g.Key
-                ).ToList();
-                foreach (var t in nonUniqueTriggers)
+                var duplicateFilters = filters.Where(ps => ps.String.Equals(t, StringComparison.InvariantCultureIgnoreCase)).ToList();
+                foreach (FilterContext fctx in Enum.GetValues(typeof(FilterContext)))
                 {
-                    var duplicateFilters = filters.Where(ps => ps.String.Equals(t, StringComparison.InvariantCultureIgnoreCase)).ToList();
-                    foreach (FilterContext fctx in Enum.GetValues(typeof(FilterContext)))
+                    if (duplicateFilters.Count(f => (f.Context & fctx) == fctx) > 1)
                     {
-                        if (duplicateFilters.Count(f => (f.Context & fctx) == fctx) > 1)
-                        {
-                            if (duplicates.TryGetValue(t, out var fctxs))
-                                duplicates[t] = fctxs | fctx;
-                            else
-                                duplicates[t] = fctx;
-                        }
+                        if (duplicates.TryGetValue(t, out var fctxDup))
+                            duplicates[t] = fctxDup | fctx;
+                        else
+                            duplicates[t] = fctx;
                     }
                 }
-                foreach (var item in filters)
-                {
-                    var ctxl = item.Context.ToString();
-                    if (duplicates.Count > 0
-                        && duplicates.TryGetValue(item.String, out var fctx)
-                        && (item.Context & fctx) != 0)
-                        ctxl = "❗ " + ctxl;
-                    table.Add(
-                        item.Id.ToString(),
-                        item.String.Sanitize(),
-                        item.ValidatingRegex,
-                        ctxl,
-                        item.Actions.ToFlagsString(),
-                        string.IsNullOrEmpty(item.CustomMessage) ? "" : "✅"
-                    );
-                }
+            }
+            foreach (var item in filters)
+            {
+                var ctxl = item.Context.ToString();
+                if (duplicates.Count > 0
+                    && duplicates.TryGetValue(item.String, out var fctx)
+                    && (item.Context & fctx) != 0)
+                    ctxl = "❗ " + ctxl;
+                table.Add(
+                    item.Id.ToString(),
+                    item.String.Sanitize(),
+                    item.ValidatingRegex ?? "",
+                    ctxl,
+                    item.Actions.ToFlagsString(),
+                    string.IsNullOrEmpty(item.CustomMessage) ? "" : "✅"
+                );
             }
             await ctx.SendAutosplitMessageAsync(table.ToString()).ConfigureAwait(false);
             await ctx.RespondAsync(FilterActionExtensions.GetLegend()).ConfigureAwait(false);
@@ -89,7 +87,7 @@ namespace CompatBot.Commands
         [Description("Adds a new content filter")]
         public async Task Add(CommandContext ctx, [RemainingText, Description("A plain string to match")] string trigger)
         {
-            using var db = new BotDb();
+            await using var db = new BotDb();
             Piracystring filter;
             if (string.IsNullOrEmpty(trigger))
                 filter = new Piracystring();
@@ -116,7 +114,7 @@ namespace CompatBot.Commands
                 await db.SaveChangesAsync().ConfigureAwait(false);
                 await msg.UpdateOrCreateMessageAsync(ctx.Channel, embed: FormatFilter(filter).WithTitle("Created a new content filter #" + filter.Id)).ConfigureAwait(false);
                 var member = ctx.Member ?? ctx.Client.GetMember(ctx.User);
-                var reportMsg = $"{member.GetMentionWithNickname()} added a new content filter: `{filter.String.Sanitize()}`";
+                var reportMsg = $"{member?.GetMentionWithNickname()} added a new content filter: `{filter.String.Sanitize()}`";
                 if (!string.IsNullOrEmpty(filter.ValidatingRegex))
                     reportMsg += $"\nValidation: `{filter.ValidatingRegex}`";
                 await ctx.Client.ReportAsync("🆕 Content filter created", reportMsg, null, ReportSeverity.Low).ConfigureAwait(false);
@@ -130,9 +128,9 @@ namespace CompatBot.Commands
         [Description("Modifies the specified content filter")]
         public async Task Edit(CommandContext ctx, [Description("Filter ID")] int id)
         {
-            using var db = new BotDb();
+            await using var db = new BotDb();
             var filter = await db.Piracystring.FirstOrDefaultAsync(ps => ps.Id == id && !ps.Disabled).ConfigureAwait(false);
-            if (filter == null)
+            if (filter is null)
             {
                 await ctx.RespondAsync("Specified filter does not exist").ConfigureAwait(false);
                 return;
@@ -144,9 +142,9 @@ namespace CompatBot.Commands
         [Command("edit")]
         public async Task Edit(CommandContext ctx, [Description("Trigger to edit"), RemainingText] string trigger)
         {
-            using var db = new BotDb();
+            await using var db = new BotDb();
             var filter = await db.Piracystring.FirstOrDefaultAsync(ps => ps.String.Equals(trigger, StringComparison.InvariantCultureIgnoreCase) && !ps.Disabled).ConfigureAwait(false);
-            if (filter == null)
+            if (filter is null)
             {
                 await ctx.RespondAsync("Specified filter does not exist").ConfigureAwait(false);
                 return;
@@ -161,7 +159,7 @@ namespace CompatBot.Commands
         {
             int removedFilters;
             var removedTriggers = new StringBuilder();
-            using (var db = new BotDb())
+            await using (var db = new BotDb())
             {
                 foreach (var f in db.Piracystring.Where(ps => ids.Contains(ps.Id) && !ps.Disabled))
                 {
@@ -181,7 +179,7 @@ namespace CompatBot.Commands
                 var filterList = removedTriggers.ToString();
                 if (removedFilters == 1)
                     filterList = filterList.TrimStart();
-                await ctx.Client.ReportAsync($"📴 Content filter{s} removed", $"{member.GetMentionWithNickname()} removed {removedFilters} content filter{s}: {filterList}".Trim(EmbedPager.MaxDescriptionLength), null, ReportSeverity.Medium).ConfigureAwait(false);
+                await ctx.Client.ReportAsync($"📴 Content filter{s} removed", $"{member?.GetMentionWithNickname()} removed {removedFilters} content filter{s}: {filterList}".Trim(EmbedPager.MaxDescriptionLength), null, ReportSeverity.Medium).ConfigureAwait(false);
             }
             ContentFilter.RebuildMatcher();
         }
@@ -195,10 +193,10 @@ namespace CompatBot.Commands
                 return;
             }
 
-            using (var db = new BotDb())
+            await using (var db = new BotDb())
             {
                 var f = await db.Piracystring.FirstOrDefaultAsync(ps => ps.String.Equals(trigger, StringComparison.InvariantCultureIgnoreCase) && !ps.Disabled).ConfigureAwait(false);
-                if (f == null)
+                if (f is null)
                 {
                     await ctx.ReactWithAsync(Config.Reactions.Failure, "Specified filter does not exist").ConfigureAwait(false);
                     return;
@@ -210,7 +208,7 @@ namespace CompatBot.Commands
 
             await ctx.ReactWithAsync(Config.Reactions.Success, "Trigger was removed").ConfigureAwait(false);
             var member = ctx.Member ?? ctx.Client.GetMember(ctx.User);
-            await ctx.Client.ReportAsync("📴 Content filter removed", $"{member.GetMentionWithNickname()} removed 1 content filter: `{trigger.Sanitize()}`", null, ReportSeverity.Medium).ConfigureAwait(false);
+            await ctx.Client.ReportAsync("📴 Content filter removed", $"{member?.GetMentionWithNickname()} removed 1 content filter: `{trigger.Sanitize()}`", null, ReportSeverity.Medium).ConfigureAwait(false);
             ContentFilter.RebuildMatcher();
         }
 
@@ -222,7 +220,7 @@ namespace CompatBot.Commands
                 await db.SaveChangesAsync().ConfigureAwait(false);
                 await msg.UpdateOrCreateMessageAsync(ctx.Channel, embed: FormatFilter(filter).WithTitle("Updated content filter")).ConfigureAwait(false);
                 var member = ctx.Member ?? ctx.Client.GetMember(ctx.User);
-                var reportMsg = $"{member.GetMentionWithNickname()} changed content filter #{filter.Id} (`{filter.Actions.ToFlagsString()}`): `{filter.String.Sanitize()}`";
+                var reportMsg = $"{member?.GetMentionWithNickname()} changed content filter #{filter.Id} (`{filter.Actions.ToFlagsString()}`): `{filter.String.Sanitize()}`";
                 if (!string.IsNullOrEmpty(filter.ValidatingRegex))
                     reportMsg += $"\nValidation: `{filter.ValidatingRegex}`";
                 await ctx.Client.ReportAsync("🆙 Content filter updated", reportMsg, null, ReportSeverity.Low).ConfigureAwait(false);
@@ -232,7 +230,19 @@ namespace CompatBot.Commands
                 await msg.UpdateOrCreateMessageAsync(ctx.Channel, "Content filter update aborted").ConfigureAwait(false);
         }
 
-        private async Task<(bool success, DiscordMessage message)> EditFilterPropertiesAsync(CommandContext ctx, BotDb db, Piracystring filter)
+        private static async Task<(bool success, DiscordMessage? message)> EditFilterPropertiesAsync(CommandContext ctx, BotDb db, Piracystring filter)
+        {
+            try
+            {
+                return await EditFilterPropertiesInternalAsync(ctx, db, filter).ConfigureAwait(false);
+            }
+            catch (Exception e)
+            {
+                Config.Log.Error(e, "Failed to edit content filter");
+                return (false, null);
+            }
+        }
+        private static async Task<(bool success, DiscordMessage? message)> EditFilterPropertiesInternalAsync(CommandContext ctx, BotDb db, Piracystring filter)
         {
             var interact = ctx.Client.GetInteractivity();
             var abort = DiscordEmoji.FromUnicode("🛑");
@@ -251,10 +261,10 @@ namespace CompatBot.Commands
             var letterE = DiscordEmoji.FromUnicode("🇪");
             var letterU = DiscordEmoji.FromUnicode("🇺");
 
-            DiscordMessage msg = null;
-            string errorMsg = null;
-            DiscordMessage txt;
-            MessageReactionAddEventArgs emoji;
+            DiscordMessage? msg = null;
+            string? errorMsg = null;
+            DiscordMessage? txt;
+            MessageReactionAddEventArgs? emoji;
 
         step1:
             // step 1: define trigger string
@@ -612,7 +622,8 @@ namespace CompatBot.Commands
                     filter.ExplainTerm = null;
                 else
                 {
-                    var existingTerm = await db.Explanation.FirstOrDefaultAsync(exp => exp.Keyword == txt.Content.ToLowerInvariant()).ConfigureAwait(false);
+                    var term = txt.Content.ToLowerInvariant();
+                    var existingTerm = await db.Explanation.FirstOrDefaultAsync(exp => exp.Keyword == term).ConfigureAwait(false);
                     if (existingTerm == null)
                     {
                         errorMsg = $"Term `{txt.Content.ToLowerInvariant().Sanitize()}` is not defined.";
@@ -694,7 +705,7 @@ namespace CompatBot.Commands
             return (false, msg);
         }
 
-        private static DiscordEmbedBuilder FormatFilter(Piracystring filter, string error = null, int highlight = -1)
+        private static DiscordEmbedBuilder FormatFilter(Piracystring filter, string? error = null, int highlight = -1)
         {
             var field = 1;
             var result = new DiscordEmbedBuilder
@@ -709,14 +720,14 @@ namespace CompatBot.Commands
             result.AddFieldEx(validTrigger + "Trigger", filter.String, highlight == field++, true)
                 .AddFieldEx("Context", filter.Context.ToString(), highlight == field++, true)
                 .AddFieldEx("Actions", filter.Actions.ToFlagsString(), highlight == field++, true)
-                .AddFieldEx("Validation", filter.ValidatingRegex, highlight == field++, true);
+                .AddFieldEx("Validation", filter.ValidatingRegex ?? "", highlight == field++, true);
             if (filter.Actions.HasFlag(FilterAction.SendMessage))
-                result.AddFieldEx("Message", filter.CustomMessage, highlight == field, true);
+                result.AddFieldEx("Message", filter.CustomMessage ?? "", highlight == field, true);
             field++;
             if (filter.Actions.HasFlag(FilterAction.ShowExplain))
             {
                 var validExplainTerm = string.IsNullOrEmpty(filter.ExplainTerm) ? "⚠ " : "";
-                result.AddFieldEx(validExplainTerm + "Explain", filter.ExplainTerm, highlight == field, true);
+                result.AddFieldEx(validExplainTerm + "Explain", filter.ExplainTerm ?? "", highlight == field, true);
             }
 #if DEBUG
             result.WithFooter("Test bot instance");

CompatBot/Commands/Explain.cs

@@ -31,7 +31,6 @@ namespace CompatBot.Commands
         [GroupCommand]
         public async Task ShowExplanation(CommandContext ctx, [RemainingText, Description("Term to explain")] string term)
         {
-            var sourceTerm = term;
             if (string.IsNullOrEmpty(term))
             {
                 var lastBotMessages = await ctx.Channel.GetMessagesBeforeCachedAsync(ctx.Message.Id, 10).ConfigureAwait(false);
@@ -55,8 +54,6 @@ namespace CompatBot.Commands
                     await ctx.ReactWithAsync(Config.Reactions.Failure).ConfigureAwait(false);
                     return;
                 }
-
-                sourceTerm = term = newMessage.Result.Content;
             }
 
             if (!await DiscordInviteFilter.CheckMessageForInvitesAsync(ctx.Client, ctx.Message).ConfigureAwait(false))
@@ -70,7 +67,7 @@ namespace CompatBot.Commands
             if (result.explanation == null || !string.IsNullOrEmpty(result.fuzzyMatch))
             {
                 term = term.StripQuotes();
-                var idx = term.LastIndexOf(" to ");
+                var idx = term.LastIndexOf(" to ", StringComparison.Ordinal);
                 if (idx > 0)
                 {
                     var potentialUserId = term[(idx + 4)..].Trim();
@@ -95,7 +92,7 @@ namespace CompatBot.Commands
             if (await SendExplanation(result, term, ctx.Message).ConfigureAwait(false))
                 return;
 
-            string inSpecificLocation = null;
+            string? inSpecificLocation = null;
             if (!LimitedToSpamChannel.IsSpamChannel(ctx.Channel))
             {
                 var spamChannel = await ctx.Client.GetChannelAsync(Config.BotSpamId).ConfigureAwait(false);
@@ -114,8 +111,8 @@ namespace CompatBot.Commands
             try
             {
                 term = term.ToLowerInvariant().StripQuotes();
-                byte[] attachment = null;
-                string attachmentFilename = null;
+                byte[]? attachment = null;
+                string? attachmentFilename = null;
                 if (ctx.Message.Attachments.FirstOrDefault() is DiscordAttachment att)
                 {
                     attachmentFilename = att.FileName;
@@ -134,7 +131,7 @@ namespace CompatBot.Commands
                     await ctx.ReactWithAsync(Config.Reactions.Failure, "An explanation for the term must be provided").ConfigureAwait(false);
                 else
                 {
-                    using var db = new BotDb();
+                    await using var db = new BotDb();
                     if (await db.Explanation.AnyAsync(e => e.Keyword == term).ConfigureAwait(false))
                         await ctx.ReactWithAsync(Config.Reactions.Failure, $"`{term}` is already defined. Use `update` to update an existing term.").ConfigureAwait(false);
                     else
@@ -163,8 +160,8 @@ namespace CompatBot.Commands
             [RemainingText, Description("New explanation text")] string explanation)
         {
             term = term.ToLowerInvariant().StripQuotes();
-            byte[] attachment = null;
-            string attachmentFilename = null;
+            byte[]? attachment = null;
+            string? attachmentFilename = null;
             if (ctx.Message.Attachments.FirstOrDefault() is DiscordAttachment att)
             {
                 attachmentFilename = att.FileName;
@@ -178,7 +175,7 @@ namespace CompatBot.Commands
                     Config.Log.Warn(e, "Failed to download explanation attachment " + ctx);
                 }
             }
-            using var db = new BotDb();
+            await using var db = new BotDb();
             var item = await db.Explanation.FirstOrDefaultAsync(e => e.Keyword == term).ConfigureAwait(false);
             if (item == null)
                 await ctx.ReactWithAsync(Config.Reactions.Failure, $"Term `{term}` is not defined").ConfigureAwait(false);
@@ -203,7 +200,7 @@ namespace CompatBot.Commands
         {
             oldTerm = oldTerm.ToLowerInvariant().StripQuotes();
             newTerm = newTerm.ToLowerInvariant().StripQuotes();
-            using var db = new BotDb();
+            await using var db = new BotDb();
             var item = await db.Explanation.FirstOrDefaultAsync(e => e.Keyword == oldTerm).ConfigureAwait(false);
             if (item == null)
                 await ctx.ReactWithAsync(Config.Reactions.Failure, $"Term `{oldTerm}` is not defined").ConfigureAwait(false);
@@ -235,7 +232,7 @@ namespace CompatBot.Commands
         public async Task List(CommandContext ctx)
         {
             var responseChannel = await ctx.GetChannelForSpamAsync().ConfigureAwait(false);
-            using var db = new BotDb();
+            await using var db = new BotDb();
             var keywords = await db.Explanation.Select(e => e.Keyword).OrderBy(t => t).ToListAsync().ConfigureAwait(false);
             if (keywords.Count == 0)
                 await ctx.RespondAsync("Nothing has been defined yet").ConfigureAwait(false);
@@ -259,7 +256,7 @@ namespace CompatBot.Commands
             public async Task RemoveExplanation(CommandContext ctx, [RemainingText, Description("Term to remove")] string term)
             {
                 term = term.ToLowerInvariant().StripQuotes();
-                using var db = new BotDb();
+                await using var db = new BotDb();
                 var item = await db.Explanation.FirstOrDefaultAsync(e => e.Keyword == term).ConfigureAwait(false);
                 if (item == null)
                     await ctx.ReactWithAsync(Config.Reactions.Failure, $"Term `{term}` is not defined").ConfigureAwait(false);
@@ -276,7 +273,7 @@ namespace CompatBot.Commands
             public async Task Attachment(CommandContext ctx, [RemainingText, Description("Term to remove")] string term)
             {
                 term = term.ToLowerInvariant().StripQuotes();
-                using var db = new BotDb();
+                await using var db = new BotDb();
                 var item = await db.Explanation.FirstOrDefaultAsync(e => e.Keyword == term).ConfigureAwait(false);
                 if (item == null)
                     await ctx.ReactWithAsync(Config.Reactions.Failure, $"Term `{term}` is not defined").ConfigureAwait(false);
@@ -298,7 +295,7 @@ namespace CompatBot.Commands
             public async Task Text(CommandContext ctx, [RemainingText, Description("Term to remove")] string term)
             {
                 term = term.ToLowerInvariant().StripQuotes();
-                using var db = new BotDb();
+                await using var db = new BotDb();
                 var item = await db.Explanation.FirstOrDefaultAsync(e => e.Keyword == term).ConfigureAwait(false);
                 if (item == null)
                     await ctx.ReactWithAsync(Config.Reactions.Failure, $"Term `{term}` is not defined").ConfigureAwait(false);
@@ -337,7 +334,7 @@ namespace CompatBot.Commands
                 return;
             }
 
-            using var db = new BotDb();
+            await using var db = new BotDb();
             var item = await db.Explanation.FirstOrDefaultAsync(e => e.Keyword == termOrLink).ConfigureAwait(false);
             if (item == null)
             {
@@ -348,21 +345,21 @@ namespace CompatBot.Commands
             {
                 if (!string.IsNullOrEmpty(item.Text))
                 {
-                    using var stream = new MemoryStream(Encoding.UTF8.GetBytes(item.Text));
+                    await using var stream = new MemoryStream(Encoding.UTF8.GetBytes(item.Text));
                     await ctx.Channel.SendFileAsync($"{termOrLink}.txt", stream).ConfigureAwait(false);
                 }
-                if (!string.IsNullOrEmpty(item.AttachmentFilename))
+                if (!string.IsNullOrEmpty(item.AttachmentFilename) && item.Attachment?.Length > 0)
                 {
-                    using var stream = new MemoryStream(item.Attachment);
+                    await using var stream = new MemoryStream(item.Attachment);
                     await ctx.Channel.SendFileAsync(item.AttachmentFilename, stream).ConfigureAwait(false);
                 }
             }
         }
 
-        internal static async Task<(Explanation explanation, string fuzzyMatch, double score)> LookupTerm(string term)
+        internal static async Task<(Explanation? explanation, string? fuzzyMatch, double score)> LookupTerm(string term)
         {
-            using var db = new BotDb();
-            string fuzzyMatch = null;
+            await using var db = new BotDb();
+            string? fuzzyMatch = null;
             double coefficient;
             var explanation = await db.Explanation.FirstOrDefaultAsync(e => e.Keyword == term).ConfigureAwait(false);
             if (explanation == null)
@@ -378,7 +375,7 @@ namespace CompatBot.Commands
             return (explanation, fuzzyMatch, coefficient);
         }
 
-        internal static async Task<bool> SendExplanation((Explanation explanation, string fuzzyMatch, double score) termLookupResult, string term, DiscordMessage sourceMessage)
+        internal static async Task<bool> SendExplanation((Explanation? explanation, string? fuzzyMatch, double score) termLookupResult, string term, DiscordMessage sourceMessage)
         {
             try
             {
@@ -410,8 +407,8 @@ namespace CompatBot.Commands
 
         private static async Task DumpLink(CommandContext ctx, string messageLink)
         {
-            string explanation = null;
-            DiscordMessage msg = null;
+            string? explanation = null;
+            DiscordMessage? msg = null;
             try { msg = await ctx.GetMessageAsync(messageLink).ConfigureAwait(false); } catch {}
             if (msg != null)
             {
@@ -425,7 +422,7 @@ namespace CompatBot.Commands
                 await ctx.ReactWithAsync(Config.Reactions.Failure, "Couldn't find any text in the specified message").ConfigureAwait(false);
             else
             {
-                using var stream = new MemoryStream(Encoding.UTF8.GetBytes(explanation));
+                await using var stream = new MemoryStream(Encoding.UTF8.GetBytes(explanation));
                 await ctx.Channel.SendFileAsync("explanation.txt", stream).ConfigureAwait(false);
             }
         }

CompatBot/Commands/Pr.cs

@@ -28,7 +28,7 @@ namespace CompatBot.Commands
         public Task List(CommandContext ctx, [Description("Get information for specific PR number")] int pr) => LinkPrBuild(ctx.Client, ctx.Message, pr);
 
         [GroupCommand]
-        public async Task List(CommandContext ctx, [Description("Get information for PRs with specified text in description. First word might be an author"), RemainingText] string searchStr = null)
+        public async Task List(CommandContext ctx, [Description("Get information for PRs with specified text in description. First word might be an author"), RemainingText] string? searchStr = null)
         {
             var openPrList = await githubClient.GetOpenPrsAsync(Config.Cts.Token).ConfigureAwait(false);
             if (openPrList == null)
@@ -45,7 +45,10 @@ namespace CompatBot.Commands
 
             if (!string.IsNullOrEmpty(searchStr))
             {
-                var filteredList = openPrList.Where(pr => pr.Title.Contains(searchStr, StringComparison.InvariantCultureIgnoreCase) || pr.User.Login.Contains(searchStr, StringComparison.InvariantCultureIgnoreCase)).ToList();
+                var filteredList = openPrList.Where(
+                    pr => pr.Title?.Contains(searchStr, StringComparison.InvariantCultureIgnoreCase) is true
+                          || pr.User?.Login?.Contains(searchStr, StringComparison.InvariantCultureIgnoreCase) is true
+                ).ToList();
                 if (filteredList.Count == 0)
                 {
                     var searchParts = searchStr.Split(' ', 2);
@@ -53,7 +56,10 @@ namespace CompatBot.Commands
                     {
                         var author = searchParts[0].Trim();
                         var substr = searchParts[1].Trim();
-                        openPrList = openPrList.Where(pr => pr.User.Login.Contains(author, StringComparison.InvariantCultureIgnoreCase) && pr.Title.Contains(substr, StringComparison.InvariantCultureIgnoreCase)).ToList();
+                        openPrList = openPrList.Where(
+                            pr => pr.User?.Login?.Contains(author, StringComparison.InvariantCultureIgnoreCase) is true
+                                  && pr.Title?.Contains(substr, StringComparison.InvariantCultureIgnoreCase) is true
+                        ).ToList();
                     }
                     else
                         openPrList = filteredList;
@@ -77,20 +83,20 @@ namespace CompatBot.Commands
             var responseChannel = await ctx.GetChannelForSpamAsync().ConfigureAwait(false);
             const int maxTitleLength = 80;
             var maxNum = openPrList.Max(pr => pr.Number).ToString().Length + 1;
-            var maxAuthor = openPrList.Max(pr => pr.User.Login.GetVisibleLength());
+            var maxAuthor = openPrList.Max(pr => (pr.User?.Login).GetVisibleLength());
             var maxTitle = Math.Min(openPrList.Max(pr => pr.Title.GetVisibleLength()), maxTitleLength);
             var result = new StringBuilder($"There are {openPrList.Count} open pull requests:\n");
             foreach (var pr in openPrList)
-                result.Append("`").Append($"{("#" + pr.Number).PadLeft(maxNum)} by {pr.User.Login.PadRightVisible(maxAuthor)}: {pr.Title.Trim(maxTitleLength).PadRightVisible(maxTitle)}".FixSpaces()).AppendLine($"` <{pr.HtmlUrl}>");
+                result.Append('`').Append($"{("#" + pr.Number).PadLeft(maxNum)} by {pr.User?.Login?.PadRightVisible(maxAuthor)}: {pr.Title?.Trim(maxTitleLength).PadRightVisible(maxTitle)}".FixSpaces()).AppendLine($"` <{pr.HtmlUrl}>");
             await responseChannel.SendAutosplitMessageAsync(result, blockStart: null, blockEnd: null).ConfigureAwait(false);
         }
 
         public static async Task LinkPrBuild(DiscordClient client, DiscordMessage message, int pr)
         {
             var prInfo = await githubClient.GetPrInfoAsync(pr, Config.Cts.Token).ConfigureAwait(false);
-            if (prInfo.Number == 0)
+            if (prInfo is null or {Number: 0})
             {
-                await message.ReactWithAsync(Config.Reactions.Failure, prInfo.Message ?? "PR not found").ConfigureAwait(false);
+                await message.ReactWithAsync(Config.Reactions.Failure, prInfo?.Message ?? "PR not found").ConfigureAwait(false);
                 return;
             }
 
@@ -100,9 +106,9 @@ namespace CompatBot.Commands
             {
                 var windowsDownloadHeader = "Windows PR Build";
                 var linuxDownloadHeader = "Linux PR Build";
-                string windowsDownloadText = null;
-                string linuxDownloadText = null;
-                string buildTime = null;
+                string? windowsDownloadText = null;
+                string? linuxDownloadText = null;
+                string? buildTime = null;
 
                 var azureClient = Config.GetAzureDevOpsClient();
                 if (azureClient != null && prInfo.Head?.Sha is string commit)
@@ -204,7 +210,7 @@ namespace CompatBot.Commands
         public static async Task LinkIssue(DiscordClient client, DiscordMessage message, int issue)
         {
             var issueInfo = await githubClient.GetIssueInfoAsync(issue, Config.Cts.Token).ConfigureAwait(false);
-            if (issueInfo.Number == 0)
+            if (issueInfo is null or {Number: 0})
                 return;
 
             if (issueInfo.PullRequest != null)

CompatBot/Commands/Sudo.Fix.cs

@@ -154,7 +154,7 @@ namespace CompatBot.Commands
                 await ctx.RespondAsync($"Fixed {changed} title{(changed == 1 ? "" : "s")}").ConfigureAwait(false);
             }
 
-            public static async Task<string> FixChannelMentionAsync(CommandContext ctx, string msg)
+            public static async Task<string?> FixChannelMentionAsync(CommandContext ctx, string? msg)
             {
                 if (string.IsNullOrEmpty(msg))
                     return msg;

CompatBot/Commands/Vision.cs

@@ -75,7 +75,7 @@ namespace CompatBot.Commands
 
         [Command("describe"), TriggersTyping]
         [Description("Generates an image description from the attached image, or from the url")]
-        public Task Describe(CommandContext ctx, [RemainingText] string imageUrl = null)
+        public Task Describe(CommandContext ctx, [RemainingText] string? imageUrl = null)
         {
             if (imageUrl?.StartsWith("tag") ?? false)
                 return Tag(ctx, imageUrl[3..].TrimStart());
@@ -84,7 +84,7 @@ namespace CompatBot.Commands
 
         [Command("tag"), TriggersTyping]
         [Description("Tags recognized objects in the image")]
-        public async Task Tag(CommandContext ctx, string imageUrl = null)
+        public async Task Tag(CommandContext ctx, string? imageUrl = null)
         {
             try
             {
@@ -92,9 +92,9 @@ namespace CompatBot.Commands
                 if (string.IsNullOrEmpty(imageUrl))
                     return;
 
-                using var imageStream = Config.MemoryStreamManager.GetStream();
+                await using var imageStream = Config.MemoryStreamManager.GetStream();
                 using (var httpClient = HttpClientFactory.Create())
-                using (var stream = await httpClient.GetStreamAsync(imageUrl).ConfigureAwait(false))
+                await using (var stream = await httpClient.GetStreamAsync(imageUrl).ConfigureAwait(false))
                     await stream.CopyToAsync(imageStream).ConfigureAwait(false);
                 imageStream.Seek(0, SeekOrigin.Begin);
 #pragma warning disable VSTHRD103
@@ -114,7 +114,7 @@ namespace CompatBot.Commands
                 if (resized || imgFormat.Name != JpegFormat.Instance.Name)
                 {
                     imageStream.SetLength(0);
-                    img.Save(imageStream, new JpegEncoder { Quality = 90 });
+                    await img.SaveAsync(imageStream, new JpegEncoder { Quality = 90 }).ConfigureAwait(false);
                     imageStream.Seek(0, SeekOrigin.Begin);
                 }
                 else
@@ -132,7 +132,7 @@ namespace CompatBot.Commands
                 {
                     quality -= 5;
                     imageStream.SetLength(0);
-                    img.Save(imageStream, new JpegEncoder {Quality = quality});
+                    await img.SaveAsync(imageStream, new JpegEncoder {Quality = quality}).ConfigureAwait(false);
                     imageStream.Seek(0, SeekOrigin.Begin);
                 }
 
@@ -159,7 +159,7 @@ namespace CompatBot.Commands
                     foreach (var obj in objects)
                     {
                         var r = obj.Rectangle;
-                        using var tmpStream = Config.MemoryStreamManager.GetStream();
+                        await using var tmpStream = Config.MemoryStreamManager.GetStream();
                         using var boxCopy = img.Clone(i => i.Crop(new Rectangle(r.X, r.Y, r.W, r.H)));
                         await boxCopy.SaveAsBmpAsync(tmpStream).ConfigureAwait(false);
                         tmpStream.Seek(0, SeekOrigin.Begin);
@@ -274,11 +274,11 @@ namespace CompatBot.Commands
                         if (bgBox.Y + bgBox.Height > img.Height)
                             bgBox.Y = img.Height - bgBox.Height;
                         drawnBoxes.Add(bgBox);
-                        var textboxColor = complementaryColor;
+                        var textBoxColor = complementaryColor;
                         var textColor = color;
                         try
                         {
-                            img.Mutate(i => i.Fill(bgSgo, textboxColor, bgBox));
+                            img.Mutate(i => i.Fill(bgSgo, textBoxColor, bgBox));
                             img.Mutate(i => i.GaussianBlur(10 * scale, Rectangle.Round(bgBox)));
                         }
                         catch (Exception ex)
@@ -297,12 +297,12 @@ namespace CompatBot.Commands
                             Config.Log.Error(ex, "Failed to generate tag label");
                         }
                     }
-                    using var resultStream = Config.MemoryStreamManager.GetStream();
+                    await using var resultStream = Config.MemoryStreamManager.GetStream();
                     quality = 95;
                     do
                     {
                         resultStream.SetLength(0);
-                        img.Save(resultStream, new JpegEncoder {Quality = 95});
+                        await img.SaveAsync(resultStream, new JpegEncoder {Quality = 95}).ConfigureAwait(false);
                         resultStream.Seek(0, SeekOrigin.Begin);
                         quality--;
                     } while (resultStream.Length > Config.AttachmentSizeLimit);
@@ -367,12 +367,12 @@ namespace CompatBot.Commands
                     await reactMsg.ReactWithAsync(DiscordEmoji.FromUnicode(emojiList[new Random().Next(emojiList.Length)])).ConfigureAwait(false);
         }
 
-        private static async Task<string> GetImageUrlAsync(CommandContext ctx, string imageUrl)
+        private static async Task<string?> GetImageUrlAsync(CommandContext ctx, string? imageUrl)
         {
             var reactMsg = ctx.Message;
             if (GetImageAttachment(reactMsg).FirstOrDefault() is DiscordAttachment attachment)
                 imageUrl = attachment.Url;
-            imageUrl = imageUrl?.Trim();
+            imageUrl = imageUrl?.Trim() ?? "";
             if (!string.IsNullOrEmpty(imageUrl)
                 && imageUrl.StartsWith('<')
                 && imageUrl.EndsWith('>'))
@@ -388,28 +388,22 @@ namespace CompatBot.Commands
                     && ctx.Channel.PermissionsFor(ctx.Client.GetMember(ctx.Guild, ctx.Client.CurrentUser)).HasPermission(Permissions.ReadMessageHistory))
                     try
                     {
-                        var previousMessages = await ctx.Channel.GetMessagesBeforeCachedAsync(ctx.Message.Id, 10).ConfigureAwait(false);
-                        var (selectedMsg, selectedAttachment) = (
+                        var previousMessages = (await ctx.Channel.GetMessagesBeforeCachedAsync(ctx.Message.Id, 10).ConfigureAwait(false))!;
+                        imageUrl = (
                             from m in previousMessages
                             where m.Attachments?.Count > 0
                             from a in GetImageAttachment(m)
-                            select (m, a)
+                            select a.Url
                         ).FirstOrDefault();
-                        if (selectedMsg != null)
-                            reactMsg = selectedMsg;
-                        imageUrl = selectedAttachment?.Url;
                         if (string.IsNullOrEmpty(imageUrl))
                         {
-
-                            var (selectedMsg2, selectedUrl) = (
+                            var selectedUrl = (
                                 from m in previousMessages
                                 where m.Embeds?.Count > 0
                                 from e in m.Embeds
                                 let url = e.Image?.Url ?? e.Image?.ProxyUrl ?? e.Thumbnail?.Url ?? e.Thumbnail?.ProxyUrl
-                                select (m, url)
+                                select url
                             ).FirstOrDefault();
-                            if (selectedMsg2 != null)
-                                reactMsg = selectedMsg2;
                             imageUrl = selectedUrl?.ToString();
                         }
                     }

CompatBot/Commands/Warnings.ListGroup.cs

@@ -38,9 +38,7 @@ namespace CompatBot.Commands
             [GroupCommand]
             [Description("List your own warning list")]
             public async Task List(CommandContext ctx)
-            {
-                await List(ctx, ctx.Message.Author).ConfigureAwait(false);
-            }
+                => await List(ctx, ctx.Message.Author).ConfigureAwait(false);
 
             [Command("users"), Aliases("top"), RequiresBotModRole, TriggersTyping]
             [Description("List users with warnings, sorted from most warned to least")]
@@ -57,19 +55,17 @@ namespace CompatBot.Commands
                         new AsciiColumn("Count", alignToRight: true),
                         new AsciiColumn("All time", alignToRight: true)
                     );
-                    using (var db = new BotDb())
+                    await using var db = new BotDb();
+                    var query = from warn in db.Warning.AsEnumerable()
+                        group warn by warn.DiscordId
+                        into userGroup
+                        let row = new {discordId = userGroup.Key, count = userGroup.Count(w => !w.Retracted), total = userGroup.Count()}
+                        orderby row.count descending
+                        select row;
+                    foreach (var row in query.Take(number))
                     {
-                        var query = from warn in db.Warning.AsEnumerable()
-                            group warn by warn.DiscordId
-                            into userGroup
-                            let row = new {discordId = userGroup.Key, count = userGroup.Count(w => !w.Retracted), total = userGroup.Count()}
-                            orderby row.count descending
-                            select row;
-                        foreach (var row in query.Take(number))
-                        {
-                            var username = await ctx.GetUserNameAsync(row.discordId).ConfigureAwait(false);
-                            table.Add(username, row.discordId.ToString(), row.count.ToString(), row.total.ToString());
-                        }
+                        var username = await ctx.GetUserNameAsync(row.discordId).ConfigureAwait(false);
+                        table.Add(username, row.discordId.ToString(), row.count.ToString(), row.total.ToString());
                     }
                     await ctx.SendAutosplitMessageAsync(new StringBuilder("Warning count per user:").Append(table)).ConfigureAwait(false);
                 }
@@ -103,7 +99,7 @@ namespace CompatBot.Commands
                     foreach (var row in query.Take(number))
                     {
                         var username = await ctx.GetUserNameAsync(row.DiscordId).ConfigureAwait(false);
-                        var timestamp = row.Timestamp.HasValue ? new DateTime(row.Timestamp.Value, DateTimeKind.Utc).ToString("u") : null;
+                        var timestamp = row.Timestamp.HasValue ? new DateTime(row.Timestamp.Value, DateTimeKind.Utc).ToString("u") : "";
                         table.Add(row.Id.ToString(), username, row.DiscordId.ToString(), timestamp, row.Reason, row.FullReason);
                     }
                 }
@@ -115,7 +111,7 @@ namespace CompatBot.Commands
             [Command("by"), Priority(1), RequiresBotModRole]
             public async Task By(CommandContext ctx, string me, [Description("Optional number of items to show. Default is 10")] int number = 10)
             {
-                if (me?.ToLowerInvariant() == "me")
+                if (me.ToLowerInvariant() == "me")
                 {
                     await By(ctx, ctx.User.Id, number).ConfigureAwait(false);
                     return;
@@ -148,33 +144,31 @@ namespace CompatBot.Commands
                     new AsciiColumn("Reason"),
                     new AsciiColumn("Context", disabled: !ctx.Channel.IsPrivate)
                 );
-                using (var db = new BotDb())
+                await using var db = new BotDb();
+                IOrderedQueryable<Warning> query;
+                if (showRetractions)
+                    query = from warn in db.Warning
+                        orderby warn.Id descending
+                        select warn;
+                else
+                    query = from warn in db.Warning
+                        where !warn.Retracted
+                        orderby warn.Id descending
+                        select warn;
+                foreach (var row in query.Take(number))
                 {
-                    IOrderedQueryable<Warning> query;
-                    if (showRetractions)
-                        query = from warn in db.Warning
-                            orderby warn.Id descending
-                            select warn;
-                    else
-                        query = from warn in db.Warning
-                            where !warn.Retracted
-                            orderby warn.Id descending
-                            select warn;
-                    foreach (var row in query.Take(number))
+                    var username = await ctx.GetUserNameAsync(row.DiscordId).ConfigureAwait(false);
+                    var modname = await ctx.GetUserNameAsync(row.IssuerId, defaultName: "Unknown mod").ConfigureAwait(false);
+                    var timestamp = row.Timestamp.HasValue ? new DateTime(row.Timestamp.Value, DateTimeKind.Utc).ToString("u") : "";
+                    if (row.Retracted)
                     {
-                        var username = await ctx.GetUserNameAsync(row.DiscordId).ConfigureAwait(false);
-                        var modname = await ctx.GetUserNameAsync(row.IssuerId, defaultName: "Unknown mod").ConfigureAwait(false);
-                        var timestamp = row.Timestamp.HasValue ? new DateTime(row.Timestamp.Value, DateTimeKind.Utc).ToString("u") : null;
-                        if (row.Retracted)
-                        {
-                            var modnameRetracted = row.RetractedBy.HasValue ? await ctx.GetUserNameAsync(row.RetractedBy.Value, defaultName: "Unknown mod").ConfigureAwait(false) : "";
-                            var timestampRetracted = row.RetractionTimestamp.HasValue ? new DateTime(row.RetractionTimestamp.Value, DateTimeKind.Utc).ToString("u") : null;
-                            table.Add(row.Id.ToString(), "-", username, row.DiscordId.ToString(), modnameRetracted, timestampRetracted, row.RetractionReason, "");
-                            table.Add(row.Id.ToString(), "+", username.StrikeThrough(), row.DiscordId.ToString().StrikeThrough(), modname.StrikeThrough(), timestamp.StrikeThrough(), row.Reason.StrikeThrough(), row.FullReason.StrikeThrough());
-                        }
-                        else
-                            table.Add(row.Id.ToString(), "+", username, row.DiscordId.ToString(), modname, timestamp, row.Reason, row.FullReason);
+                        var modnameRetracted = row.RetractedBy.HasValue ? await ctx.GetUserNameAsync(row.RetractedBy.Value, defaultName: "Unknown mod").ConfigureAwait(false) : "";
+                        var timestampRetracted = row.RetractionTimestamp.HasValue ? new DateTime(row.RetractionTimestamp.Value, DateTimeKind.Utc).ToString("u") : "";
+                        table.Add(row.Id.ToString(), "-", username, row.DiscordId.ToString(), modnameRetracted, timestampRetracted, row.RetractionReason ?? "", "");
+                        table.Add(row.Id.ToString(), "+", username.StrikeThrough(), row.DiscordId.ToString().StrikeThrough(), modname.StrikeThrough(), timestamp.StrikeThrough(), row.Reason.StrikeThrough(), row.FullReason.StrikeThrough());
                     }
+                    else
+                        table.Add(row.Id.ToString(), "+", username, row.DiscordId.ToString(), modname, timestamp, row.Reason, row.FullReason);
                 }
                 await ctx.SendAutosplitMessageAsync(new StringBuilder("Recent warnings:").Append(table)).ConfigureAwait(false);
             }

CompatBot/Commands/Warnings.cs

@@ -51,7 +51,11 @@ namespace CompatBot.Commands
         {
             var interact = ctx.Client.GetInteractivity();
             var msg = await ctx.RespondAsync("What is the reason for removal?").ConfigureAwait(false);
-            var response = await interact.WaitForMessageAsync(m => m.Author == ctx.User && m.Channel == ctx.Channel && !string.IsNullOrEmpty(m.Content)).ConfigureAwait(false);
+            var response = await interact.WaitForMessageAsync(
+                m => m.Author == ctx.User
+                     && m.Channel == ctx.Channel
+                     && !string.IsNullOrEmpty(m.Content)
+            ).ConfigureAwait(false);
             if (string.IsNullOrEmpty(response.Result?.Content))
             {
                 await msg.UpdateOrCreateMessageAsync(ctx.Channel, "Can't remove warnings without a reason").ConfigureAwait(false);
@@ -59,19 +63,16 @@ namespace CompatBot.Commands
             }
 
             await msg.DeleteAsync().ConfigureAwait(false);
-            int removedCount;
-            using (var db = new BotDb())
+            await using var db = new BotDb();
+            var warningsToRemove = await db.Warning.Where(w => ids.Contains(w.Id)).ToListAsync().ConfigureAwait(false);
+            foreach (var w in warningsToRemove)
             {
-                var warningsToRemove = await db.Warning.Where(w => ids.Contains(w.Id)).ToListAsync().ConfigureAwait(false);
-                foreach (var w in warningsToRemove)
-                {
-                    w.Retracted = true;
-                    w.RetractedBy = ctx.User.Id;
-                    w.RetractionReason = response.Result.Content;
-                    w.RetractionTimestamp = DateTime.UtcNow.Ticks;
-                }
-                removedCount = await db.SaveChangesAsync().ConfigureAwait(false);
+                w.Retracted = true;
+                w.RetractedBy = ctx.User.Id;
+                w.RetractionReason = response.Result.Content;
+                w.RetractionTimestamp = DateTime.UtcNow.Ticks;
             }
+            var removedCount = await db.SaveChangesAsync().ConfigureAwait(false);
             if (removedCount == ids.Length)
                 await ctx.RespondAsync($"Warning{StringUtils.GetSuffix(ids.Length)} successfully removed!").ConfigureAwait(false);
             else
@@ -81,9 +82,7 @@ namespace CompatBot.Commands
         [Command("clear"), RequiresBotModRole]
         [Description("Removes **all** warnings for a user")]
         public Task Clear(CommandContext ctx, [Description("User to clear warnings for")] DiscordUser user)
-        {
-            return Clear(ctx, user.Id);
-        }
+            => Clear(ctx, user.Id);
 
         [Command("clear"), RequiresBotModRole]
         public async Task Clear(CommandContext ctx, [Description("User ID to clear warnings for")] ulong userId)
@@ -100,19 +99,16 @@ namespace CompatBot.Commands
             await msg.DeleteAsync().ConfigureAwait(false);
             try
             {
-                int removed;
-                using (var db = new BotDb())
+                await using var db = new BotDb();
+                var warningsToRemove = await db.Warning.Where(w => w.DiscordId == userId).ToListAsync().ConfigureAwait(false);
+                foreach (var w in warningsToRemove)
                 {
-                    var warningsToRemove = await db.Warning.Where(w => w.DiscordId == userId).ToListAsync().ConfigureAwait(false);
-                    foreach (var w in warningsToRemove)
-                    {
-                        w.Retracted = true;
-                        w.RetractedBy = ctx.User.Id;
-                        w.RetractionReason = response.Result.Content;
-                        w.RetractionTimestamp = DateTime.UtcNow.Ticks;
-                    }
-                    removed = await db.SaveChangesAsync().ConfigureAwait(false);
+                    w.Retracted = true;
+                    w.RetractedBy = ctx.User.Id;
+                    w.RetractionReason = response.Result.Content;
+                    w.RetractionTimestamp = DateTime.UtcNow.Ticks;
                 }
+                var removed = await db.SaveChangesAsync().ConfigureAwait(false);
                 await ctx.RespondAsync($"{removed} warning{StringUtils.GetSuffix(removed)} successfully removed!").ConfigureAwait(false);
             }
             catch (Exception e)
@@ -125,7 +121,7 @@ namespace CompatBot.Commands
         [Description("Changes the state of the warning status")]
         public async Task Revert(CommandContext ctx, [Description("Warning ID to change")] int id)
         {
-            using var db = new BotDb();
+            await using var db = new BotDb();
             var warn = await db.Warning.FirstOrDefaultAsync(w => w.Id == id).ConfigureAwait(false);
             if (warn.Retracted)
             {
@@ -140,45 +136,47 @@ namespace CompatBot.Commands
                 await Remove(ctx, id).ConfigureAwait(false);
         }
 
-        internal static async Task<bool> AddAsync(CommandContext ctx, ulong userId, string userName, DiscordUser issuer, string reason, string fullReason = null)
+        internal static async Task<bool> AddAsync(CommandContext ctx, ulong userId, string userName, DiscordUser issuer, string? reason, string? fullReason = null)
         {
             reason = await Sudo.Fix.FixChannelMentionAsync(ctx, reason).ConfigureAwait(false);
             return await AddAsync(ctx.Client, ctx.Message, userId, userName, issuer, reason, fullReason);
         }
 
-        internal static async Task<bool> AddAsync(DiscordClient client, DiscordMessage message, ulong userId, string userName, DiscordUser issuer, string reason, string fullReason = null)
+        internal static async Task<bool> AddAsync(DiscordClient client, DiscordMessage message, ulong userId, string userName, DiscordUser issuer, string? reason, string? fullReason = null)
         {
             if (string.IsNullOrEmpty(reason))
             {
                 var interact = client.GetInteractivity();
                 var msg = await message.Channel.SendMessageAsync("What is the reason for this warning?").ConfigureAwait(false);
-                var response = await interact.WaitForMessageAsync(m => m.Author == message.Author && m.Channel == message.Channel && !string.IsNullOrEmpty(m.Content)).ConfigureAwait(false);
+                var response = await interact.WaitForMessageAsync(
+                    m => m.Author == message.Author
+                         && m.Channel == message.Channel
+                         && !string.IsNullOrEmpty(m.Content)
+                ).ConfigureAwait(false);
                 if (string.IsNullOrEmpty(response.Result.Content))
                 {
                     await msg.UpdateOrCreateMessageAsync(message.Channel, "A reason needs to be provided").ConfigureAwait(false);
                     return false;
                 }
+                
                 await msg.DeleteAsync().ConfigureAwait(false);
                 reason = response.Result.Content;
             }
             try
             {
-                int totalCount;
-                using (var db = new BotDb())
+                await using var db = new BotDb();
+                await db.Warning.AddAsync(new Warning { DiscordId = userId, IssuerId = issuer.Id, Reason = reason, FullReason = fullReason ?? "", Timestamp = DateTime.UtcNow.Ticks }).ConfigureAwait(false);
+                await db.SaveChangesAsync().ConfigureAwait(false);
+
+                var threshold = DateTime.UtcNow.AddMinutes(-15).Ticks;
+                var recentCount = db.Warning.Count(w => w.DiscordId == userId && !w.Retracted && w.Timestamp > threshold);
+                if (recentCount > 3)
                 {
-                    await db.Warning.AddAsync(new Warning { DiscordId = userId, IssuerId = issuer.Id, Reason = reason, FullReason = fullReason ?? "", Timestamp = DateTime.UtcNow.Ticks }).ConfigureAwait(false);
-                    await db.SaveChangesAsync().ConfigureAwait(false);
-
-                    var threshold = DateTime.UtcNow.AddMinutes(-15).Ticks;
-                    var recentCount = db.Warning.Count(w => w.DiscordId == userId && !w.Retracted && w.Timestamp > threshold);
-                    if (recentCount > 3)
-                    {
-                        Config.Log.Debug("Suicide behavior detected, not spamming with warning responses");
-                        return true;
-                    }
-
-                    totalCount = db.Warning.Count(w => w.DiscordId == userId && !w.Retracted);
+                    Config.Log.Debug("Suicide behavior detected, not spamming with warning responses");
+                    return true;
                 }
+
+                var totalCount = db.Warning.Count(w => w.DiscordId == userId && !w.Retracted);
                 await message.RespondAsync($"User warning saved! User currently has {totalCount} warning{StringUtils.GetSuffix(totalCount)}!").ConfigureAwait(false);
                 if (totalCount > 1)
                     await ListUserWarningsAsync(client, message, userId, userName).ConfigureAwait(false);
@@ -196,7 +194,7 @@ namespace CompatBot.Commands
         {
             try
             {
-                var isWhitelisted = client.GetMember(message.Author)?.IsWhitelisted() ?? false;
+                var isWhitelisted = client.GetMember(message.Author)?.IsWhitelisted() is true;
                 if (message.Author.Id != userId && !isWhitelisted)
                 {
                     Config.Log.Error($"Somehow {message.Author.Username} ({message.Author.Id}) triggered warning list for {userId}");
@@ -207,13 +205,11 @@ namespace CompatBot.Commands
                 var isPrivate = channel.IsPrivate;
                 int count, removed;
                 bool isKot, isDoggo;
-                using (var db = new BotDb())
-                {
-                    count = await db.Warning.CountAsync(w => w.DiscordId == userId && !w.Retracted).ConfigureAwait(false);
-                    removed = await db.Warning.CountAsync(w => w.DiscordId == userId && w.Retracted).ConfigureAwait(false);
-                    isKot = db.Kot.Any(k => k.UserId == userId);
-                    isDoggo = db.Doggo.Any(d => d.UserId == userId);
-                }
+                await using var db = new BotDb();
+                count = await db.Warning.CountAsync(w => w.DiscordId == userId && !w.Retracted).ConfigureAwait(false);
+                removed = await db.Warning.CountAsync(w => w.DiscordId == userId && w.Retracted).ConfigureAwait(false);
+                isKot = db.Kot.Any(k => k.UserId == userId);
+                isDoggo = db.Doggo.Any(d => d.UserId == userId);
                 if (count == 0)
                 {
                     if (isKot && isDoggo)
@@ -225,12 +221,12 @@ namespace CompatBot.Commands
                     }
                     var msg = (removed, isPrivate, isKot, isDoggo) switch
                     {
-                        (0, _, true, false) => $"{userName} has no warnings, is an upstanding kot, and a paw bean of this community",
-                        (0, _, false, true) => $"{userName} has no warnings, is a good boy, and a wiggling tail of this community",
-                        (0, _,  _, _) => $"{userName} has no warnings, is an upstanding citizen, and a pillar of this community",
-                        (_, true, _, _) => $"{userName} has no warnings ({removed} retracted warning{(removed == 1 ? "" : "s")})",
-                        (_, _, true, false) => $"{userName} has no warnings, but are they a good kot?",
-                        (_, _, false, true) => $"{userName} has no warnings, but are they a good boy?",
+                        (0,    _,  true, false) => $"{userName} has no warnings, is an upstanding kot, and a paw bean of this community",
+                        (0,    _, false,  true) => $"{userName} has no warnings, is a good boy, and a wiggling tail of this community",
+                        (0,    _,     _,     _) => $"{userName} has no warnings, is an upstanding citizen, and a pillar of this community",
+                        (_, true,     _,     _) => $"{userName} has no warnings ({removed} retracted warning{(removed == 1 ? "" : "s")})",
+                        (_,    _,  true, false) => $"{userName} has no warnings, but are they a good kot?",
+                        (_,    _, false,  true) => $"{userName} has no warnings, but are they a good boy?",
                         _ => $"{userName} has no warnings",
                     };
                     await message.RespondAsync(msg).ConfigureAwait(false);
@@ -242,62 +238,59 @@ namespace CompatBot.Commands
                     return;
 
                 const int maxWarningsInPublicChannel = 3;
-                using (var db = new BotDb())
+                var showCount = Math.Min(maxWarningsInPublicChannel, count);
+                var table = new AsciiTable(
+                    new AsciiColumn("ID", alignToRight: true),
+                    new AsciiColumn("±", disabled: !isPrivate || !isWhitelisted),
+                    new AsciiColumn("By", maxWidth: 15),
+                    new AsciiColumn("On date (UTC)"),
+                    new AsciiColumn("Reason"),
+                    new AsciiColumn("Context", disabled: !isPrivate, maxWidth: 4096)
+                );
+                IQueryable<Warning> query = db.Warning.Where(w => w.DiscordId == userId).OrderByDescending(w => w.Id);
+                if (!isPrivate || !isWhitelisted)
+                    query = query.Where(w => !w.Retracted);
+                if (!isPrivate && !isWhitelisted)
+                    query = query.Take(maxWarningsInPublicChannel);
+                foreach (var warning in await query.ToListAsync().ConfigureAwait(false))
                 {
-                    var showCount = Math.Min(maxWarningsInPublicChannel, count);
-                    var table = new AsciiTable(
-                        new AsciiColumn("ID", alignToRight: true),
-                        new AsciiColumn("±", disabled: !isPrivate || !isWhitelisted),
-                        new AsciiColumn("By", maxWidth: 15),
-                        new AsciiColumn("On date (UTC)"),
-                        new AsciiColumn("Reason"),
-                        new AsciiColumn("Context", disabled: !isPrivate, maxWidth: 4096)
-                        );
-                    IQueryable<Warning> query = db.Warning.Where(w => w.DiscordId == userId).OrderByDescending(w => w.Id);
-                    if (!isPrivate || !isWhitelisted)
-                        query = query.Where(w => !w.Retracted);
-                    if (!isPrivate && !isWhitelisted)
-                        query = query.Take(maxWarningsInPublicChannel);
-                    foreach (var warning in await query.ToListAsync().ConfigureAwait(false))
+                    if (warning.Retracted)
                     {
-                        if (warning.Retracted)
+                        if (isWhitelisted && isPrivate)
                         {
-                            if (isWhitelisted && isPrivate)
-                            {
-                                var retractedByName = !warning.RetractedBy.HasValue
-                                    ? ""
-                                    : await client.GetUserNameAsync(channel, warning.RetractedBy.Value, isPrivate, "unknown mod").ConfigureAwait(false);
-                                var retractionTimestamp = warning.RetractionTimestamp.HasValue
-                                    ? new DateTime(warning.RetractionTimestamp.Value, DateTimeKind.Utc).ToString("u")
-                                    : null;
-                                table.Add(warning.Id.ToString(), "-", retractedByName, retractionTimestamp, warning.RetractionReason, "");
+                            var retractedByName = warning.RetractedBy.HasValue
+                                ? await client.GetUserNameAsync(channel, warning.RetractedBy.Value, isPrivate, "unknown mod").ConfigureAwait(false)
+                                : "";
+                            var retractionTimestamp = warning.RetractionTimestamp.HasValue
+                                ? new DateTime(warning.RetractionTimestamp.Value, DateTimeKind.Utc).ToString("u")
+                                : "";
+                            table.Add(warning.Id.ToString(), "-", retractedByName, retractionTimestamp, warning.RetractionReason ?? "", "");
 
-                                var issuerName = warning.IssuerId == 0
-                                    ? ""
-                                    : await client.GetUserNameAsync(channel, warning.IssuerId, isPrivate, "unknown mod").ConfigureAwait(false);
-                                var timestamp = warning.Timestamp.HasValue
-                                    ? new DateTime(warning.Timestamp.Value, DateTimeKind.Utc).ToString("u")
-                                    : null;
-                                table.Add(warning.Id.ToString().StrikeThrough(), "+", issuerName.StrikeThrough(), timestamp.StrikeThrough(), warning.Reason.StrikeThrough(), warning.FullReason.StrikeThrough());
-                            }
-                        }
-                        else
-                        {
                             var issuerName = warning.IssuerId == 0
                                 ? ""
                                 : await client.GetUserNameAsync(channel, warning.IssuerId, isPrivate, "unknown mod").ConfigureAwait(false);
                             var timestamp = warning.Timestamp.HasValue
                                 ? new DateTime(warning.Timestamp.Value, DateTimeKind.Utc).ToString("u")
-                                : null;
-                            table.Add(warning.Id.ToString(), "+", issuerName, timestamp, warning.Reason, warning.FullReason);
+                                : "";
+                            table.Add(warning.Id.ToString().StrikeThrough(), "+", issuerName.StrikeThrough(), timestamp.StrikeThrough(), warning.Reason.StrikeThrough(), warning.FullReason.StrikeThrough());
                         }
                     }
-                    var result = new StringBuilder("Warning list for ").Append(userName);
-                    if (!isPrivate && !isWhitelisted && count > maxWarningsInPublicChannel)
-                        result.Append($" (last {showCount} of {count}, full list in DMs)");
-                    result.AppendLine(":").Append(table);
-                    await channel.SendAutosplitMessageAsync(result).ConfigureAwait(false);
+                    else
+                    {
+                        var issuerName = warning.IssuerId == 0
+                            ? ""
+                            : await client.GetUserNameAsync(channel, warning.IssuerId, isPrivate, "unknown mod").ConfigureAwait(false);
+                        var timestamp = warning.Timestamp.HasValue
+                            ? new DateTime(warning.Timestamp.Value, DateTimeKind.Utc).ToString("u")
+                            : "";
+                        table.Add(warning.Id.ToString(), "+", issuerName, timestamp, warning.Reason, warning.FullReason);
+                    }
                 }
+                var result = new StringBuilder("Warning list for ").Append(userName);
+                if (!isPrivate && !isWhitelisted && count > maxWarningsInPublicChannel)
+                    result.Append($" (last {showCount} of {count}, full list in DMs)");
+                result.AppendLine(":").Append(table);
+                await channel.SendAutosplitMessageAsync(result).ConfigureAwait(false);
             }
             catch (Exception e)
             {

CompatBot/CompatBot.csproj

@@ -10,6 +10,7 @@
     <NoWarn>1701;1702;VSTHRD200</NoWarn>
     <DockerDefaultTargetOS>Linux</DockerDefaultTargetOS>
     <ConcurrentGarbageCollection>true</ConcurrentGarbageCollection>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>
@@ -58,7 +59,6 @@
     <PackageReference Include="Microsoft.VisualStudio.Azure.Containers.Tools.Targets" Version="1.10.8" />
     <PackageReference Include="Microsoft.VisualStudio.Services.Client" Version="16.153.0" />
     <PackageReference Include="Nerdbank.Streams" Version="2.6.81" />
-    <PackageReference Include="Newtonsoft.Json" Version="12.0.3" />
     <PackageReference Include="NLog" Version="4.7.5" />
     <PackageReference Include="NLog.Extensions.Logging" Version="1.6.5" />
     <PackageReference Include="NReco.Text.AhoCorasickDoubleArrayTrie" Version="1.0.2" />

CompatBot/Config.cs

@@ -30,8 +30,8 @@ namespace CompatBot
 {
     internal static class Config
     {
-        private static IConfigurationRoot config;
-        private static TelemetryClient telemetryClient;
+        private static IConfigurationRoot config = null!;
+        private static TelemetryClient? telemetryClient;
         private static readonly DependencyTrackingTelemetryModule dependencyTrackingTelemetryModule = new DependencyTrackingTelemetryModule();
         private static readonly PerformanceCollectorModule performanceCollectorModule = new PerformanceCollectorModule();
 
@@ -101,9 +101,9 @@ namespace CompatBot
                 if (SandboxDetector.Detect() == SandboxType.Docker)
                     return "/bot-config/credentials.json";
 
-                if (Assembly.GetEntryAssembly().GetCustomAttribute<UserSecretsIdAttribute>() is UserSecretsIdAttribute attribute)
+                if (Assembly.GetEntryAssembly()?.GetCustomAttribute<UserSecretsIdAttribute>() is UserSecretsIdAttribute attribute
+                    && Path.GetDirectoryName(PathHelper.GetSecretsPathFromSecretsId(attribute.UserSecretsId)) is string path)
                 {
-                    var path = Path.GetDirectoryName(PathHelper.GetSecretsPathFromSecretsId(attribute.UserSecretsId));
                     path = Path.Combine(path, "credentials.json");
                     if (File.Exists(path))
                         return path;
@@ -217,6 +217,7 @@ namespace CompatBot
                 Console.ForegroundColor = ConsoleColor.Red;
                 Console.WriteLine("Error initializing settings: " + e.Message);
                 Console.ResetColor();
+                throw;
             }
         }
 
@@ -231,7 +232,7 @@ namespace CompatBot
 
         private static ILogger GetLog()
         {
-            var config = new NLog.Config.LoggingConfiguration();
+            var loggingConfig = new NLog.Config.LoggingConfiguration();
             var fileTarget = new FileTarget("logfile") {
                 FileName = CurrentLogPath,
                 ArchiveEvery = FileArchivePeriod.Day,
@@ -266,25 +267,25 @@ namespace CompatBot
                 new MethodCallParameter("${message}"),
             });
 #if DEBUG
-            config.AddRule(LogLevel.Trace, LogLevel.Fatal, consoleTarget, "default"); // only echo messages from default logger to the console
+            loggingConfig.AddRule(LogLevel.Trace, LogLevel.Fatal, consoleTarget, "default"); // only echo messages from default logger to the console
 #else
-            config.AddRule(LogLevel.Info, LogLevel.Fatal, consoleTarget, "default");
+            loggingConfig.AddRule(LogLevel.Info, LogLevel.Fatal, consoleTarget, "default");
 #endif
-            config.AddRule(LogLevel.Debug, LogLevel.Fatal, asyncFileTarget);
-            config.AddRule(LogLevel.Info, LogLevel.Fatal, watchdogTarget);
+            loggingConfig.AddRule(LogLevel.Debug, LogLevel.Fatal, asyncFileTarget);
+            loggingConfig.AddRule(LogLevel.Info, LogLevel.Fatal, watchdogTarget);
 
             var ignoreFilter1 = new ConditionBasedFilter { Condition = "contains('${message}','TaskCanceledException')", Action = FilterResult.Ignore, };
             var ignoreFilter2 = new ConditionBasedFilter { Condition = "contains('${message}','One or more pre-execution checks failed')", Action = FilterResult.Ignore, };
-            foreach (var rule in config.LoggingRules)
+            foreach (var rule in loggingConfig.LoggingRules)
             {
                 rule.Filters.Add(ignoreFilter1);
                 rule.Filters.Add(ignoreFilter2);
             }
-            LogManager.Configuration = config;
+            LogManager.Configuration = loggingConfig;
             return LogManager.GetLogger("default");
         }
 
-        public static BuildHttpClient GetAzureDevOpsClient()
+        public static BuildHttpClient? GetAzureDevOpsClient()
         {
             if (string.IsNullOrEmpty(AzureDevOpsToken))
                 return null;
@@ -294,14 +295,14 @@ namespace CompatBot
             return azureConnection.GetClient<BuildHttpClient>();
         }
 
-        public static TelemetryClient TelemetryClient
+        public static TelemetryClient? TelemetryClient
         {
             get
             {
                 if (string.IsNullOrEmpty(AzureAppInsightsKey))
                     return null;
 
-                if (telemetryClient != null && telemetryClient.InstrumentationKey == AzureAppInsightsKey)
+                if (telemetryClient?.InstrumentationKey == AzureAppInsightsKey)
                     return telemetryClient;
 
                 var telemetryConfig = TelemetryConfiguration.CreateDefault();

CompatBot/Database/BotDb.cs

@@ -8,18 +8,18 @@ namespace CompatBot.Database
 {
     internal class BotDb: DbContext
     {
-        public DbSet<BotState> BotState { get; set; }
-        public DbSet<Moderator> Moderator { get; set; }
-        public DbSet<Piracystring> Piracystring { get; set; }
-        public DbSet<Warning> Warning { get; set; }
-        public DbSet<Explanation> Explanation { get; set; }
-        public DbSet<DisabledCommand> DisabledCommands { get; set; }
-        public DbSet<WhitelistedInvite> WhitelistedInvites { get; set; }
-        public DbSet<EventSchedule> EventSchedule { get; set; }
-        public DbSet<Stats> Stats { get; set; }
-        public DbSet<Kot> Kot { get; set; }
-        public DbSet<Doggo> Doggo { get; set; }
-        public DbSet<ForcedNickname> ForcedNicknames { get; set; }
+        public DbSet<BotState> BotState { get; set; } = null!;
+        public DbSet<Moderator> Moderator { get; set; } = null!;
+        public DbSet<Piracystring> Piracystring { get; set; } = null!;
+        public DbSet<Warning> Warning { get; set; } = null!;
+        public DbSet<Explanation> Explanation { get; set; } = null!;
+        public DbSet<DisabledCommand> DisabledCommands { get; set; } = null!;
+        public DbSet<WhitelistedInvite> WhitelistedInvites { get; set; } = null!;
+        public DbSet<EventSchedule> EventSchedule { get; set; } = null!;
+        public DbSet<Stats> Stats { get; set; } = null!;
+        public DbSet<Kot> Kot { get; set; } = null!;
+        public DbSet<Doggo> Doggo { get; set; } = null!;
+        public DbSet<ForcedNickname> ForcedNicknames { get; set; } = null!;
         protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
         {
             var dbPath = DbImporter.GetDbPath("bot.db", Environment.SpecialFolder.ApplicationData);
@@ -58,8 +58,8 @@ namespace CompatBot.Database
     internal class BotState
     {
         public int Id { get; set; }
-        public string Key { get; set; }
-        public string Value { get; set; }
+        public string? Key { get; set; }
+        public string? Value { get; set; }
     }
 
     internal class Moderator
@@ -73,12 +73,12 @@ namespace CompatBot.Database
     {
         public int Id { get; set; }
         [Required, Column(TypeName = "varchar(255)")]
-        public string String { get; set; }
-        public string ValidatingRegex { get; set; }
+        public string String { get; set; } = null!;
+        public string? ValidatingRegex { get; set; }
         public FilterContext Context { get; set; }
         public FilterAction Actions { get; set; }
-        public string ExplainTerm { get; set; }
-        public string CustomMessage { get; set; }
+        public string? ExplainTerm { get; set; }
+        public string? CustomMessage { get; set; }
         public bool Disabled { get; set; }
     }
 
@@ -106,13 +106,13 @@ namespace CompatBot.Database
         public ulong DiscordId { get; set; }
         public ulong IssuerId { get; set; }
         [Required]
-        public string Reason { get; set; }
+        public string Reason { get; set; } = null!;
         [Required]
-        public string FullReason { get; set; }
+        public string FullReason { get; set; } = null!;
         public long? Timestamp { get; set; }
         public bool Retracted { get; set; }
         public ulong? RetractedBy { get; set; }
-        public string RetractionReason { get; set; }
+        public string? RetractionReason { get; set; }
         public long? RetractionTimestamp { get; set; }
     }
 
@@ -120,27 +120,27 @@ namespace CompatBot.Database
     {
         public int Id { get; set; }
         [Required]
-        public string Keyword { get; set; }
+        public string Keyword { get; set; } = null!;
         [Required]
-        public string Text { get; set; }
+        public string Text { get; set; } = null!;
         [MaxLength(7*1024*1024)]
-        public byte[] Attachment { get; set; }
-        public string AttachmentFilename { get; set; }
+        public byte[]? Attachment { get; set; }
+        public string? AttachmentFilename { get; set; }
     }
 
     internal class DisabledCommand
     {
         public int Id { get; set; }
         [Required]
-        public string Command { get; set; }
+        public string Command { get; set; } = null!;
     }
 
     internal class WhitelistedInvite
     {
         public int Id { get; set; }
         public ulong GuildId { get; set; }
-        public string Name { get; set; }
-        public string InviteCode { get; set; }
+        public string? Name { get; set; }
+        public string? InviteCode { get; set; }
     }
 
     internal class EventSchedule
@@ -149,17 +149,17 @@ namespace CompatBot.Database
         public int Year { get; set; }
         public long Start { get; set; }
         public long End { get; set; }
-        public string Name { get; set; }
-        public string EventName { get; set; }
+        public string? Name { get; set; }
+        public string? EventName { get; set; }
     }
 
     internal class Stats
     {
         public int Id { get; set; }
         [Required]
-        public string Category { get; set; }
+        public string Category { get; set; } = null!;
         [Required]
-        public string Key { get; set; }
+        public string Key { get; set; } = null!;
         public int Value { get; set; }
         public long ExpirationTimestamp { get; set; }
     }
@@ -182,6 +182,6 @@ namespace CompatBot.Database
         public ulong GuildId { set; get; }
         public ulong UserId { set; get; }
         [Required]
-        public string Nickname { get; set; }
+        public string Nickname { get; set; } = null!;
     }
 }

CompatBot/Database/Providers/ThumbnailProvider.cs

@@ -9,7 +9,9 @@ using CompatBot.Utils;
 using DSharpPlus;
 using DSharpPlus.Entities;
 using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.ChangeTracking;
 using Microsoft.Extensions.Caching.Memory;
+using PsnClient.POCOs;
 
 namespace CompatBot.Database.Providers
 {
@@ -19,8 +21,11 @@ namespace CompatBot.Database.Providers
         private static readonly PsnClient.Client PsnClient = new PsnClient.Client();
         private static readonly MemoryCache ColorCache = new MemoryCache(new MemoryCacheOptions{ ExpirationScanFrequency = TimeSpan.FromDays(1) });
 
-        public static async Task<string> GetThumbnailUrlAsync(this DiscordClient client, string productCode)
+        public static async Task<string?> GetThumbnailUrlAsync(this DiscordClient client, string? productCode)
         {
+            if (string.IsNullOrEmpty(productCode))
+                return null;
+            
             productCode = productCode.ToUpperInvariant();
             var tmdbInfo = await PsnClient.GetTitleMetaAsync(productCode, Config.Cts.Token).ConfigureAwait(false);
             if (tmdbInfo?.Icon.Url is string tmdbIconUrl)
@@ -38,11 +43,8 @@ namespace CompatBot.Database.Providers
                     var gameTdbCoverUrl = await GameTdbScraper.GetThumbAsync(productCode).ConfigureAwait(false);
                     if (!string.IsNullOrEmpty(gameTdbCoverUrl))
                     {
-                        if (thumb == null)
-                        {
-                            var addResult = await db.Thumbnail.AddAsync(new Thumbnail {ProductCode = productCode, Url = gameTdbCoverUrl}).ConfigureAwait(false);
-                            thumb = addResult.Entity;
-                        }
+                        if (thumb is null)
+                            thumb = (await db.Thumbnail.AddAsync(new Thumbnail {ProductCode = productCode, Url = gameTdbCoverUrl}).ConfigureAwait(false)).Entity;
                         else
                             thumb.Url = gameTdbCoverUrl;
                         thumb.Timestamp = DateTime.UtcNow.Ticks;
@@ -53,47 +55,43 @@ namespace CompatBot.Database.Providers
                 if (thumb?.Url is string url && !string.IsNullOrEmpty(url))
                 {
                     var contentName = (thumb.ContentId ?? thumb.ProductCode);
-                    var embed = await GetEmbeddableUrlAsync(client, contentName, url).ConfigureAwait(false);
-
-                    if (embed.url != null)
+                    var (embedUrl, _) = await GetEmbeddableUrlAsync(client, contentName, url).ConfigureAwait(false);
+                    if (embedUrl != null)
                     {
-                        thumb.EmbeddableUrl = embed.url;
+                        thumb.EmbeddableUrl = embedUrl;
                         await db.SaveChangesAsync().ConfigureAwait(false);
-                        return embed.url;
+                        return embedUrl;
                     }
                 }
             }
             return null;
         }
 
-        public static async Task<string> GetTitleNameAsync(string productCode, CancellationToken cancellationToken)
+        public static async Task<string?> GetTitleNameAsync(string? productCode, CancellationToken cancellationToken)
         {
             if (string.IsNullOrEmpty(productCode))
                 return null;
 
             productCode = productCode.ToUpperInvariant();
-            using var db = new ThumbnailDb();
+            await using var db = new ThumbnailDb();
             var thumb = await db.Thumbnail.FirstOrDefaultAsync(
                 t => t.ProductCode == productCode,
                 cancellationToken: cancellationToken
             ).ConfigureAwait(false);
-            if (thumb?.Name is string title)
-                return title;
+            if (thumb?.Name is string result)
+                return result;
 
-            var meta = await PsnClient.GetTitleMetaAsync(productCode, cancellationToken).ConfigureAwait(false);
-            title = meta?.Name;
+            var title = (await PsnClient.GetTitleMetaAsync(productCode, cancellationToken).ConfigureAwait(false))?.Name;
             try
             {
                 if (!string.IsNullOrEmpty(title))
                 {
                     if (thumb == null)
-                        thumb = (
-                            await db.Thumbnail.AddAsync(new Thumbnail
-                            {
-                                ProductCode = productCode,
-                                Name = title,
-                            }, cancellationToken).ConfigureAwait(false)
-                        ).Entity;
+                        await db.Thumbnail.AddAsync(new Thumbnail
+                        {
+                            ProductCode = productCode,
+                            Name = title,
+                        }, cancellationToken).ConfigureAwait(false);
                     else
                         thumb.Name = title;
                     await db.SaveChangesAsync(cancellationToken).ConfigureAwait(false);
@@ -107,38 +105,38 @@ namespace CompatBot.Database.Providers
             return title;
         }
 
-        public static async Task<(string url, DiscordColor color)> GetThumbnailUrlWithColorAsync(DiscordClient client, string contentId, DiscordColor defaultColor, string url = null)
+        public static async Task<(string? url, DiscordColor color)> GetThumbnailUrlWithColorAsync(DiscordClient client, string contentId, DiscordColor defaultColor, string? url = null)
         {
             if (string.IsNullOrEmpty(contentId))
                 throw new ArgumentException("ContentID can't be empty", nameof(contentId));
 
             contentId = contentId.ToUpperInvariant();
-            using var db = new ThumbnailDb();
+            await using var db = new ThumbnailDb();
             var info = await db.Thumbnail.FirstOrDefaultAsync(ti => ti.ContentId == contentId, Config.Cts.Token).ConfigureAwait(false);
             info ??= new Thumbnail{Url = url};
-            if (info.Url == null)
+            if (info.Url is null)
                 return (null, defaultColor);
 
             DiscordColor? analyzedColor = null;
             if (string.IsNullOrEmpty(info.EmbeddableUrl))
             {
-                var em = await GetEmbeddableUrlAsync(client, contentId, info.Url).ConfigureAwait(false);
-                if (em.url is string eUrl)
+                var (embedUrl, image) = await GetEmbeddableUrlAsync(client, contentId, info.Url).ConfigureAwait(false);
+                if (embedUrl is string eUrl)
                 {
                     info.EmbeddableUrl = eUrl;
-                    if (em.image is byte[] jpg)
+                    if (image is byte[] jpg)
                     {
                         Config.Log.Trace("Getting dominant color for " + eUrl);
                         analyzedColor = ColorGetter.Analyze(jpg, defaultColor);
-                        var c = analyzedColor.Value.Value;
-                        if (c != defaultColor.Value)
-                            info.EmbedColor = c;
+                        if (analyzedColor.HasValue
+                            && analyzedColor.Value.Value != defaultColor.Value)
+                            info.EmbedColor = analyzedColor.Value.Value;
                     }
                     await db.SaveChangesAsync(Config.Cts.Token).ConfigureAwait(false);
                 }
             }
-            if ((!info.EmbedColor.HasValue && !analyzedColor.HasValue)
-                || (info.EmbedColor.HasValue && info.EmbedColor.Value == defaultColor.Value))
+            if (!info.EmbedColor.HasValue && !analyzedColor.HasValue
+                || info.EmbedColor.HasValue && info.EmbedColor.Value == defaultColor.Value)
             {
                 var c = await GetImageColorAsync(info.EmbeddableUrl, defaultColor).ConfigureAwait(false);
                 if (c.HasValue && c.Value.Value != defaultColor.Value)
@@ -151,15 +149,15 @@ namespace CompatBot.Database.Providers
             return (info.EmbeddableUrl, color);
         }
 
-        public static async Task<(string url, byte[] image)> GetEmbeddableUrlAsync(DiscordClient client, string contentId, string url)
+        public static async Task<(string? url, byte[]? image)> GetEmbeddableUrlAsync(DiscordClient client, string contentId, string url)
         {
             try
             {
                 if (!string.IsNullOrEmpty(Path.GetExtension(url)))
                     return (url, null);
 
-                using var imgStream = await HttpClient.GetStreamAsync(url).ConfigureAwait(false);
-                using var memStream = Config.MemoryStreamManager.GetStream();
+                await using var imgStream = await HttpClient.GetStreamAsync(url).ConfigureAwait(false);
+                await using var memStream = Config.MemoryStreamManager.GetStream();
                 await imgStream.CopyToAsync(memStream).ConfigureAwait(false);
                 // minimum jpg size is 119 bytes, png is 67 bytes
                 if (memStream.Length < 64)
@@ -168,7 +166,7 @@ namespace CompatBot.Database.Providers
                 memStream.Seek(0, SeekOrigin.Begin);
                 var spam = await client.GetChannelAsync(Config.ThumbnailSpamId).ConfigureAwait(false);
                 var message = await spam.SendFileAsync(contentId + ".jpg", memStream, contentId).ConfigureAwait(false);
-                url = message.Attachments.First().Url;
+                url = message.Attachments[0].Url;
                 return (url, memStream.ToArray());
             }
             catch (Exception e)
@@ -178,7 +176,7 @@ namespace CompatBot.Database.Providers
             return (null, null);
         }
 
-        public static async Task<DiscordColor?> GetImageColorAsync(string url, DiscordColor? defaultColor = null)
+        public static async Task<DiscordColor?> GetImageColorAsync(string? url, DiscordColor? defaultColor = null)
         {
             try
             {
@@ -188,8 +186,8 @@ namespace CompatBot.Database.Providers
                 if (ColorCache.TryGetValue(url, out DiscordColor? result))
                     return result;
 
-                using var imgStream = await HttpClient.GetStreamAsync(url).ConfigureAwait(false);
-                using var memStream = Config.MemoryStreamManager.GetStream();
+                await using var imgStream = await HttpClient.GetStreamAsync(url).ConfigureAwait(false);
+                await using var memStream = Config.MemoryStreamManager.GetStream();
                 await imgStream.CopyToAsync(memStream).ConfigureAwait(false);
                 // minimum jpg size is 119 bytes, png is 67 bytes
                 if (memStream.Length < 64)

CompatBot/Database/ThumbnailDb.cs

@@ -8,11 +8,11 @@ namespace CompatBot.Database
 {
     internal class ThumbnailDb: DbContext
     {
-        public DbSet<State> State { get; set; }
-        public DbSet<Thumbnail> Thumbnail { get; set; }
-        public DbSet<SyscallInfo> SyscallInfo { get; set; }
-        public DbSet<SyscallToProductMap> SyscallToProductMap { get; set; }
-        public DbSet<Metacritic> Metacritic { get; set; }
+        public DbSet<State> State { get; set; } = null!;
+        public DbSet<Thumbnail> Thumbnail { get; set; } = null!;
+        public DbSet<SyscallInfo> SyscallInfo { get; set; } = null!;
+        public DbSet<SyscallToProductMap> SyscallToProductMap { get; set; } = null!;
+        public DbSet<Metacritic> Metacritic { get; set; } = null!;
 
         protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
         {
@@ -45,7 +45,7 @@ namespace CompatBot.Database
     internal class State
     {
         public int Id { get; set; }
-        public string Locale { get; set; }
+        public string? Locale { get; set; }
         public long Timestamp { get; set; }
     }
 
@@ -53,20 +53,20 @@ namespace CompatBot.Database
     {
         public int Id { get; set; }
         [Required]
-        public string ProductCode { get; set; }
-        public string ContentId { get; set; }
-        public string Name { get; set; }
-        public string Url { get; set; }
-        public string EmbeddableUrl { get; set; }
+        public string ProductCode { get; set; } = null!;
+        public string? ContentId { get; set; }
+        public string? Name { get; set; }
+        public string? Url { get; set; }
+        public string? EmbeddableUrl { get; set; }
         public long Timestamp { get; set; }
         public int? EmbedColor { get; set; }
         public CompatStatus? CompatibilityStatus { get; set; }
         public long? CompatibilityChangeDate { get; set; }
 
         public int? MetacriticId { get; set; }
-        public Metacritic Metacritic { get; set; }
+        public Metacritic? Metacritic { get; set; }
 
-        public List<SyscallToProductMap> SyscallToProductMap { get; set; }
+        public List<SyscallToProductMap> SyscallToProductMap { get; set; } = null!;
     }
 
     public enum CompatStatus : byte
@@ -83,28 +83,28 @@ namespace CompatBot.Database
     {
         public int Id { get; set; }
         [Required]
-        public string Function { get; set; }
+        public string Function { get; set; } = null!;
 
-        public List<SyscallToProductMap> SyscallToProductMap { get; set; }
+        public List<SyscallToProductMap> SyscallToProductMap { get; set; } = null!;
     }
 
     internal class SyscallToProductMap
     {
         public int ProductId { get; set; }
-        public Thumbnail Product { get; set; }
+        public Thumbnail Product { get; set; } = null!;
 
         public int SyscallInfoId { get; set; }
-        public SyscallInfo SyscallInfo { get; set; }
+        public SyscallInfo SyscallInfo { get; set; } = null!;
     }
 
     internal class Metacritic
     {
         public int Id { get; set; }
         [Required]
-        public string Title { get; set; }
+        public string Title { get; set; } = null!;
         public byte? CriticScore { get; set; }
         public byte? UserScore { get; set; }
-        public string Notes { get; set; }
+        public string? Notes { get; set; }
 
         public Metacritic WithTitle(string title)
         {

CompatBot/EventHandlers/BotReactionsHandler.cs

@@ -127,7 +127,7 @@ namespace CompatBot.EventHandlers
 
             if (!string.IsNullOrEmpty(args.Message.Content) && Paws.Matches(args.Message.Content) is MatchCollection mc)
             {
-                using var db = new BotDb();
+                await using var db = new BotDb();
                 var matchedGroups = (from m in mc
                         from Group g in m.Groups
                         where g.Success && !string.IsNullOrEmpty(g.Value)
@@ -138,7 +138,7 @@ namespace CompatBot.EventHandlers
                 {
                     if (!db.Kot.Any(k => k.UserId == args.Author.Id))
                     {
-                        db.Kot.Add(new Kot {UserId = args.Author.Id});
+                        await db.Kot.AddAsync(new Kot {UserId = args.Author.Id}).ConfigureAwait(false);
                         await db.SaveChangesAsync().ConfigureAwait(false);
                     }
                 }
@@ -146,7 +146,7 @@ namespace CompatBot.EventHandlers
                 {
                     if (!db.Doggo.Any(d => d.UserId == args.Author.Id))
                     {
-                        db.Doggo.Add(new Doggo {UserId = args.Author.Id});
+                        await db.Doggo.AddAsync(new Doggo {UserId = args.Author.Id}).ConfigureAwait(false);
                         await db.SaveChangesAsync().ConfigureAwait(false);
                     }
                 }
@@ -159,7 +159,7 @@ namespace CompatBot.EventHandlers
             if (needToThank)
             {
                 DiscordEmoji emoji;
-                string thankYouMessage;
+                string? thankYouMessage;
                 lock (theDoor)
                 {
                     emoji = ThankYouReactions[rng.Next(ThankYouReactions.Length)];
@@ -198,7 +198,7 @@ namespace CompatBot.EventHandlers
 
         internal static (bool needToChill, bool needToThank) NeedToSilence(DiscordMessage msg)
         {
-            if (string.IsNullOrEmpty(msg?.Content))
+            if (string.IsNullOrEmpty(msg.Content))
                 return (false, false);
 
             var needToChill = false;
@@ -211,7 +211,7 @@ namespace CompatBot.EventHandlers
                                                   else
                                                       needToThank = true;
                                               });
-            var mentionsBot = msgContent.Contains("bot") || (msg.MentionedUsers?.Any(u => { try { return u.IsCurrent; } catch { return false; }}) ?? false);
+            var mentionsBot = msgContent.Contains("bot") || msg.MentionedUsers?.Any(u => { try { return u.IsCurrent; } catch { return false; }}) is true;
             return (needToChill && mentionsBot, needToThank && mentionsBot);
         }
     }

CompatBot/EventHandlers/DiscordInviteFilter.cs

@@ -183,7 +183,7 @@ namespace CompatBot.EventHandlers
             if (string.IsNullOrEmpty(message))
                 return (false, false, new List<DiscordInvite>(0));
 
-            var inviteCodes = new HashSet<string>(InviteLink.Matches(message).Select(m => m.Groups["invite_id"]?.Value).Where(s => !string.IsNullOrEmpty(s)));
+            var inviteCodes = new HashSet<string>(InviteLink.Matches(message).Select(m => m.Groups["invite_id"].Value).Where(s => !string.IsNullOrEmpty(s)));
             var discordMeLinks = InviteLink.Matches(message).Select(m => m.Groups["me_id"]?.Value).Distinct().Where(s => !string.IsNullOrEmpty(s)).ToList();
             var attemptedWorkaround = false;
             if (author != null && InviteCodeCache.TryGetValue(author.Id, out HashSet<string> recentInvites))
@@ -236,25 +236,34 @@ namespace CompatBot.EventHandlers
                                 {
                                     ["_token"] = csrfTokenMatch.Groups["csrf_token"].Value,
                                     ["serverEid"] = serverEidMatch.Groups["server_eid"].Value,
-                                }),
+                                }!),
                             };
                             postRequest.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("text/html"));
                             postRequest.Headers.UserAgent.Add(new ProductInfoHeaderValue("RPCS3CompatibilityBot", "2.0"));
                             using var postResponse = await httpClient.SendAsync(postRequest).ConfigureAwait(false);
                             if (postResponse.StatusCode == HttpStatusCode.Redirect)
                             {
-                                var redirectId = postResponse.Headers.Location.Segments.Last();
-                                using var getDiscordRequest = new HttpRequestMessage(HttpMethod.Get, "https://discord.me/server/join/redirect/" + redirectId);
-                                getDiscordRequest.Headers.CacheControl = CacheControlHeaderValue.Parse("no-cache");
-                                getDiscordRequest.Headers.UserAgent.Add(new ProductInfoHeaderValue("RPCS3CompatibilityBot", "2.0"));
-                                using var discordRedirect = await httpClient.SendAsync(getDiscordRequest).ConfigureAwait(false);
-                                if (discordRedirect.StatusCode == HttpStatusCode.Redirect)
+                                var redirectId = postResponse.Headers.Location?.Segments.Last();
+                                if (redirectId != null)
                                 {
-                                    inviteCodes.Add(discordRedirect.Headers.Location.Segments.Last());
-                                    hasInvalidInvites = false;
+                                    using var getDiscordRequest = new HttpRequestMessage(HttpMethod.Get, "https://discord.me/server/join/redirect/" + redirectId);
+                                    getDiscordRequest.Headers.CacheControl = CacheControlHeaderValue.Parse("no-cache");
+                                    getDiscordRequest.Headers.UserAgent.Add(new ProductInfoHeaderValue("RPCS3CompatibilityBot", "2.0"));
+                                    using var discordRedirect = await httpClient.SendAsync(getDiscordRequest).ConfigureAwait(false);
+                                    if (discordRedirect.StatusCode == HttpStatusCode.Redirect)
+                                    {
+                                        var inviteCodeSegment = discordRedirect.Headers.Location?.Segments.Last();
+                                        if (inviteCodeSegment != null)
+                                        {
+                                            inviteCodes.Add(inviteCodeSegment);
+                                            hasInvalidInvites = false;
+                                        }
+                                    }
+                                    else
+                                        Config.Log.Warn($"Unexpected response code from GET discord redirect: {discordRedirect.StatusCode}");
                                 }
                                 else
-                                    Config.Log.Warn($"Unexpected response code from GET discord redirect: {discordRedirect.StatusCode}");
+                                    Config.Log.Warn($"Failed to get redirection URL from {postResponse.RequestMessage?.RequestUri}");
                             }
                             else
                                 Config.Log.Warn($"Unexpected response code from POST: {postResponse.StatusCode}");

CompatBot/EventHandlers/GithubLinksHandler.cs

@@ -34,7 +34,7 @@ namespace CompatBot.EventHandlers
                     return;
 
             lastBotMessages = await args.Channel.GetMessagesBeforeCachedAsync(args.Message.Id, Config.ProductCodeLookupHistoryThrottle).ConfigureAwait(false);
-            StringBuilder previousRepliesBuilder = null;
+            StringBuilder? previousRepliesBuilder = null;
             foreach (var msg in lastBotMessages)
             {
                 if (msg.Author.IsCurrent)

CompatBot/EventHandlers/IsTheGamePlayableHandler.cs

@@ -32,7 +32,7 @@ namespace CompatBot.EventHandlers
 
         public static async Task OnMessageCreated(DiscordClient c, MessageCreateEventArgs args)
         {
-            if (DefaultHandlerFilter.IsFluff(args?.Message))
+            if (DefaultHandlerFilter.IsFluff(args.Message))
                 return;
 
 #if !DEBUG
@@ -92,7 +92,7 @@ namespace CompatBot.EventHandlers
             CooldownBuckets[args.Channel.Id] = DateTime.UtcNow;
         }
 
-        public static async Task<(string productCode, TitleInfo info)> LookupGameAsync(DiscordChannel channel, DiscordMessage message, string gameTitle)
+        public static async Task<(string? productCode, TitleInfo? info)> LookupGameAsync(DiscordChannel channel, DiscordMessage message, string gameTitle)
         {
             var lastBotMessages = await channel.GetMessagesBeforeAsync(message.Id, 20, DateTime.UtcNow.AddSeconds(-30)).ConfigureAwait(false);
             foreach (var msg in lastBotMessages)
@@ -105,36 +105,38 @@ namespace CompatBot.EventHandlers
                 var searchCompatListTask = Client.GetCompatResultAsync(requestBuilder, Config.Cts.Token);
                 var localList = CompatList.GetLocalCompatResult(requestBuilder);
                 var status = await searchCompatListTask.ConfigureAwait(false);
-                status = status.Append(localList);
-                if ((status.ReturnCode == 0 || status.ReturnCode == 2) && status.Results.Any())
+                status = status?.Append(localList);
+                if (status is null
+                    || status.ReturnCode != 0 && status.ReturnCode != 2
+                    || !status.Results.Any())
+                    return (null, null);
+                
+                var sortedList = status.GetSortedList();
+                var bestMatch = sortedList.First();
+                var listWithStatus = sortedList
+                    .TakeWhile(i => Math.Abs(i.score - bestMatch.score) < double.Epsilon)
+                    .Where(i => !string.IsNullOrEmpty(i.info.Status) && i.info.Status != "Unknown")
+                    .ToList();
+                if (listWithStatus.Count > 0)
+                    bestMatch = listWithStatus.First();
+                var (code, info, score) = bestMatch;
+                Config.Log.Debug($"Looked up \"{gameTitle}\", got \"{info?.Title}\" with score {score}");
+                if (score < Config.GameTitleMatchThreshold)
+                    return (null, null);
+
+                if (!string.IsNullOrEmpty(info?.Title))
                 {
-                    var sortedList = status.GetSortedList();
-                    var bestMatch = sortedList.First();
-                    var listWithStatus = sortedList
-                        .TakeWhile(i => Math.Abs(i.score - bestMatch.score) < double.Epsilon)
-                        .Where(i => !string.IsNullOrEmpty(i.info.Status) && i.info.Status != "Unknown")
-                        .ToList();
-                    if (listWithStatus.Count > 0)
-                        bestMatch = listWithStatus.First();
-                    var (code, info, score) = bestMatch;
-                    Config.Log.Debug($"Looked up \"{gameTitle}\", got \"{info?.Title}\" with score {score}");
-                    if (score < Config.GameTitleMatchThreshold)
-                        return (null, null);
-
-                    if (!string.IsNullOrEmpty(info?.Title))
-                    {
-                        StatsStorage.GameStatCache.TryGetValue(info.Title, out int stat);
-                        StatsStorage.GameStatCache.Set(info.Title, ++stat, StatsStorage.CacheTime);
-                    }
-
-                    return (code, info);
+                    StatsStorage.GameStatCache.TryGetValue(info.Title, out int stat);
+                    StatsStorage.GameStatCache.Set(info.Title, ++stat, StatsStorage.CacheTime);
                 }
+
+                return (code, info);
             }
             catch (Exception e)
             {
                 Config.Log.Warn(e);
+                return (null, null);
             }
-            return (null, null);
         }
     }
 }

CompatBot/EventHandlers/ProductCodeLookup.cs

@@ -27,28 +27,24 @@ namespace CompatBot.EventHandlers
                 return;
 
             var lastBotMessages = await args.Channel.GetMessagesBeforeAsync(args.Message.Id, 20, DateTime.UtcNow.AddSeconds(-30)).ConfigureAwait(false);
-            foreach (var msg in lastBotMessages)
-                if (BotReactionsHandler.NeedToSilence(msg).needToChill)
-                    return;
+            if (lastBotMessages.Any(msg => BotReactionsHandler.NeedToSilence(msg).needToChill))
+                return;
 
             lastBotMessages = await args.Channel.GetMessagesBeforeCachedAsync(args.Message.Id, Config.ProductCodeLookupHistoryThrottle).ConfigureAwait(false);
-            StringBuilder previousRepliesBuilder = null;
-            foreach (var msg in lastBotMessages)
+            StringBuilder? previousRepliesBuilder = null;
+            foreach (var msg in lastBotMessages.Where(m => m.Author.IsCurrent))
             {
-                if (msg.Author.IsCurrent)
-                {
-                    previousRepliesBuilder ??= new StringBuilder();
-                    previousRepliesBuilder.AppendLine(msg.Content);
-                    var embeds = msg.Embeds;
-                    if (embeds?.Count > 0)
-                        foreach (var embed in embeds)
-                            previousRepliesBuilder.AppendLine(embed.Title).AppendLine(embed.Description);
-                }
+                previousRepliesBuilder ??= new StringBuilder();
+                previousRepliesBuilder.AppendLine(msg.Content);
+                var embeds = msg.Embeds;
+                if (embeds?.Count > 0)
+                    foreach (var embed in embeds)
+                        previousRepliesBuilder.AppendLine(embed.Title).AppendLine(embed.Description);
             }
             var previousReplies = previousRepliesBuilder?.ToString() ?? "";
 
             var codesToLookup = GetProductIds(args.Message.Content)
-                .Where(c => !previousReplies.Contains(c, StringComparison.InvariantCultureIgnoreCase))
+                .Where(pc => !previousReplies.Contains(pc, StringComparison.InvariantCultureIgnoreCase))
                 .Take(args.Channel.IsPrivate ? 50 : 5)
                 .ToList();
             if (codesToLookup.Count == 0)
@@ -95,7 +91,7 @@ namespace CompatBot.EventHandlers
             }
         }
 
-        public static List<string> GetProductIds(string input)
+        public static List<string> GetProductIds(string? input)
         {
             if (string.IsNullOrEmpty(input))
                 return new List<string>(0);
@@ -106,7 +102,7 @@ namespace CompatBot.EventHandlers
                 .ToList();
         }
 
-        public static async Task<DiscordEmbedBuilder> LookupGameInfoAsync(this DiscordClient client, string code, string gameTitle = null, bool forLog = false, string category = null)
+        public static async Task<DiscordEmbedBuilder> LookupGameInfoAsync(this DiscordClient client, string? code, string? gameTitle = null, bool forLog = false, string? category = null)
         {
             if (string.IsNullOrEmpty(code))
                 return TitleInfo.Unknown.AsEmbed(code, gameTitle, forLog);
@@ -167,7 +163,7 @@ namespace CompatBot.EventHandlers
                     titleInfoEmbed.Title.Contains("afrika", StringComparison.InvariantCultureIgnoreCase)
                 ))
             {
-                var sqvat = client.GetEmoji(":sqvat:", Config.Reactions.No);
+                var sqvat = client.GetEmoji(":sqvat:", Config.Reactions.No)!;
                 titleInfoEmbed.Title = "How about no (๑•ิཬ•ั๑)";
                 if (!string.IsNullOrEmpty(titleInfoEmbed.Thumbnail?.Url))
                     titleInfoEmbed.WithThumbnail("https://cdn.discordapp.com/attachments/417347469521715210/516340151589535745/onionoff.png");

CompatBot/EventHandlers/UnknownCommandHandler.cs

@@ -54,11 +54,12 @@ namespace CompatBot.EventHandlers
             if (cnfe.CommandName.Length < 3)
                 return;
 
-            var pos = e.Context.Message?.Content?.IndexOf(cnfe.CommandName) ?? -1;
+            var content = e.Context.Message.Content;
+            var pos = content?.IndexOf(cnfe.CommandName) ?? -1;
             if (pos < 0)
                 return;
 
-            var gameTitle = e.Context.Message.Content[pos..].TrimEager().Trim(40);
+            var gameTitle = content![pos..].TrimEager().Trim(40);
             if (string.IsNullOrEmpty(gameTitle) || char.IsPunctuation(gameTitle[0]))
                 return;
 
@@ -123,7 +124,6 @@ namespace CompatBot.EventHandlers
                 return;
             }
 
-
             var ch = await e.Context.GetChannelForSpamAsync().ConfigureAwait(false);
             await ch.SendMessageAsync(
                 $"I am not sure what you wanted me to do, please use one of the following commands:\n" +
@@ -165,6 +165,6 @@ namespace CompatBot.EventHandlers
             return allKnownBotCommands;
         }
 
-        private static List<string> allKnownBotCommands;
+        private static List<string>? allKnownBotCommands;
     }
 }

CompatBot/EventHandlers/UsernameSpoofMonitor.cs

@@ -26,14 +26,17 @@ namespace CompatBot.EventHandlers
             if (args.UserBefore.Username == args.UserAfter.Username)
                 return;
 
-            var potentialTargets = GetPotentialVictims(c, c.GetMember(args.UserAfter), true, false);
+            var m = c.GetMember(args.UserAfter);
+            if (m is null)
+                return;
+            
+            var potentialTargets = GetPotentialVictims(c, m, true, false);
             if (!potentialTargets.Any())
                 return;
 
             if (await IsFlashmobAsync(c, potentialTargets).ConfigureAwait(false))
                 return;
 
-            var m = c.GetMember(args.UserAfter);
             await c.ReportAsync("🕵️ Potential user impersonation",
                 $"User {m.GetMentionWithNickname()} has changed their __username__ from " +
                 $"**{args.UserBefore.Username.Sanitize()}#{args.UserBefore.Discriminator}** to " +
@@ -77,7 +80,7 @@ namespace CompatBot.EventHandlers
                 ReportSeverity.Medium);
         }
 
-        internal static List<DiscordMember> GetPotentialVictims(DiscordClient client, DiscordMember newMember, bool checkUsername, bool checkNickname, List<DiscordMember> listToCheckAgainst = null)
+        internal static List<DiscordMember> GetPotentialVictims(DiscordClient client, DiscordMember newMember, bool checkUsername, bool checkNickname, List<DiscordMember>? listToCheckAgainst = null)
         {
             var membersWithRoles = listToCheckAgainst ??
                                    client.Guilds.SelectMany(guild => guild.Value.Members.Values)
@@ -125,28 +128,27 @@ namespace CompatBot.EventHandlers
 
         private static string GetCanonical(string name)
         {
-            string result;
             if (UsernameLock.Wait(0))
                 try
                 {
-                    if (UsernameMapping.TryGetValue(name, out result))
+                    if (UsernameMapping.TryGetValue(name, out var result))
                         return result;
                 }
                 finally
                 {
                     UsernameLock.Release();
                 }
-            result = name.ToCanonicalForm();
+            var canonicalName = name.ToCanonicalForm();
             if (UsernameLock.Wait(0))
                 try
                 {
-                    UsernameMapping[name] = result;
+                    UsernameMapping[name] = canonicalName;
                 }
                 finally
                 {
                     UsernameLock.Release();
                 }
-            return result;
+            return canonicalName;
         }
     }
 }

CompatBot/EventHandlers/UsernameValidationMonitor.cs

@@ -24,10 +24,10 @@ namespace CompatBot.EventHandlers
                 if (guildMember.IsWhitelisted())
                     return;
 
-                if (!(guild.Permissions?.HasFlag(Permissions.ChangeNickname) ?? true))
+                if (guild.Permissions?.HasFlag(Permissions.ChangeNickname) is false)
                     return;
 
-                using var db = new BotDb();
+                await using var db = new BotDb();
                 var forcedNickname = await db.ForcedNicknames.AsNoTracking().FirstOrDefaultAsync(x => x.UserId == guildMember.Id && x.GuildId == guildMember.Guild.Id).ConfigureAwait(false);
                 if (forcedNickname is null)
                     return;
@@ -51,46 +51,48 @@ namespace CompatBot.EventHandlers
             {
                 if (!once)
                     await Task.Delay(Config.ForcedNicknamesRecheckTimeInHours, Config.Cts.Token).ConfigureAwait(false);
-                if (await Moderation.Audit.CheckLock.WaitAsync(0).ConfigureAwait(false))
-                    try
-                    {
-                        foreach (var guild in client.Guilds.Values)
+                if (!await Moderation.Audit.CheckLock.WaitAsync(0).ConfigureAwait(false))
+                    continue;
+                
+                try
+                {
+                    foreach (var guild in client.Guilds.Values)
+                        try
                         {
-                            try
+                            if (guild.Permissions?.HasFlag(Permissions.ChangeNickname) is false)
+                                continue;
+
+                            await using var db = new BotDb();
+                            var forcedNicknames = await db.ForcedNicknames
+                                .Where(mem => mem.GuildId == guild.Id)
+                                .ToListAsync()
+                                .ConfigureAwait(false);
+                            if (forcedNicknames.Count == 0)
+                                continue;
+
+                            foreach (var forced in forcedNicknames)
                             {
-                                if (!(guild.Permissions?.HasFlag(Permissions.ChangeNickname) ?? true))
+                                var member = client.GetMember(guild, forced.UserId);
+                                if (member is null || member.DisplayName == forced.Nickname)
                                     continue;
-
-                                using var db = new BotDb();
-                                var forcedNicknames = await db.ForcedNicknames
-                                    .Where(mem => mem.GuildId == guild.Id)
-                                    .ToListAsync()
-                                    .ConfigureAwait(false);
-                                if (forcedNicknames.Count == 0)
-                                    continue;
-
-                                foreach (var forced in forcedNicknames)
+                                
+                                try
                                 {
-                                    var member = client.GetMember(guild, forced.UserId);
-                                    if (member?.DisplayName != forced.Nickname)
-                                        try
-                                        {
-                                            await member.ModifyAsync(mem => mem.Nickname = forced.Nickname).ConfigureAwait(false);
-                                            Config.Log.Info($"Enforced nickname {forced.Nickname} for user {member.Id} ({member.Username}#{member.Discriminator})");
-                                        }
-                                        catch {}
+                                    await member.ModifyAsync(mem => mem.Nickname = forced.Nickname).ConfigureAwait(false);
+                                    Config.Log.Info($"Enforced nickname {forced.Nickname} for user {member.Id} ({member.Username}#{member.Discriminator})");
                                 }
-                            }
-                            catch (Exception e)
-                            {
-                                Config.Log.Error(e);
+                                catch { }
                             }
                         }
-                    }
-                    finally
-                    {
-                        Moderation.Audit.CheckLock.Release();
-                    }
+                        catch (Exception e)
+                        {
+                            Config.Log.Error(e);
+                        }
+                }
+                finally
+                {
+                    Moderation.Audit.CheckLock.Release();
+                }
             } while (!Config.Cts.IsCancellationRequested && !once);
         }
     }

CompatBot/EventHandlers/UsernameZalgoMonitor.cs

@@ -22,15 +22,15 @@ namespace CompatBot.EventHandlers
         {
             try
             {
-                var m = c.GetMember(args.UserAfter);
-                if (NeedsRename(m.DisplayName))
+                if (c.GetMember(args.UserAfter) is DiscordMember m
+                    && NeedsRename(m.DisplayName))
                 {
                     var suggestedName = StripZalgo(m.DisplayName, m.Id).Sanitize();
                     await c.ReportAsync("🔣 Potential display name issue",
                         $"User {m.GetMentionWithNickname()} has changed their __username__ and is now shown as **{m.DisplayName.Sanitize()}**\nAutomatically renamed to: **{suggestedName}**",
                         null,
                         ReportSeverity.Medium);
-                    await DmAndRenameUserAsync(c, c.GetMember(args.UserAfter), suggestedName).ConfigureAwait(false);
+                    await DmAndRenameUserAsync(c, m, suggestedName).ConfigureAwait(false);
                 }
             }
             catch (Exception e)
@@ -85,7 +85,7 @@ namespace CompatBot.EventHandlers
 
         public static bool NeedsRename(string displayName)
         {
-            displayName = displayName?.Normalize().TrimEager();
+            displayName = displayName.Normalize().TrimEager();
             return displayName != StripZalgo(displayName, 0ul, NormalizationForm.FormC, 3);
         }
 
@@ -111,7 +111,7 @@ namespace CompatBot.EventHandlers
 
         public static string StripZalgo(string displayName, ulong userId, NormalizationForm normalizationForm = NormalizationForm.FormD, int level = 0)
         {
-            displayName = displayName?.Normalize(normalizationForm).TrimEager();
+            displayName = displayName.Normalize(normalizationForm).TrimEager();
             if (string.IsNullOrEmpty(displayName))
                 return "Rule #7 Breaker #" + userId.GetHashCode().ToString("x8");
 

CompatBot/ThumbScrapper/GameTdbScraper.cs

@@ -43,7 +43,7 @@ namespace CompatBot.ThumbScrapper
             } while (!cancellationToken.IsCancellationRequested);
         }
 
-        public static async Task<string> GetThumbAsync(string productCode)
+        public static async Task<string?> GetThumbAsync(string productCode)
         {
             try
             {
@@ -72,63 +72,58 @@ namespace CompatBot.ThumbScrapper
                     return;
 
                 Config.Log.Debug("Scraping GameTDB for game titles...");
-                using (var fileStream = new FileStream(Path.GetTempFileName(), FileMode.Create, FileAccess.ReadWrite, FileShare.Read, 16384, FileOptions.Asynchronous | FileOptions.RandomAccess | FileOptions.DeleteOnClose))
+                await using var fileStream = new FileStream(Path.GetTempFileName(), FileMode.Create, FileAccess.ReadWrite, FileShare.Read, 16384, FileOptions.Asynchronous | FileOptions.RandomAccess | FileOptions.DeleteOnClose);
+                await using (var downloadStream = await HttpClient.GetStreamAsync(TitleDownloadLink, cancellationToken).ConfigureAwait(false))
+                    await downloadStream.CopyToAsync(fileStream, 16384, cancellationToken).ConfigureAwait(false);
+                fileStream.Seek(0, SeekOrigin.Begin);
+                using var zipArchive = new ZipArchive(fileStream, ZipArchiveMode.Read);
+                var logEntry = zipArchive.Entries.FirstOrDefault(e => e.Name.EndsWith(".xml", StringComparison.InvariantCultureIgnoreCase));
+                if (logEntry == null)
+                    throw new InvalidOperationException("No zip entries that match the .xml criteria");
+
+                await using var zipStream = logEntry.Open();
+                using var xmlReader = XmlReader.Create(zipStream, new XmlReaderSettings { Async = true });
+                xmlReader.ReadToFollowing("PS3TDB");
+                var version = xmlReader.GetAttribute("version");
+                if (!DateTime.TryParseExact(version, "yyyyMMddHHmmss", CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal, out var timestamp))
+                    return;
+
+                if (ScrapeStateProvider.IsFresh("PS3TDB", timestamp))
                 {
-                    using (var downloadStream = await HttpClient.GetStreamAsync(TitleDownloadLink).ConfigureAwait(false))
-                        await downloadStream.CopyToAsync(fileStream, 16384, cancellationToken).ConfigureAwait(false);
-                    fileStream.Seek(0, SeekOrigin.Begin);
-                    using var zipArchive = new ZipArchive(fileStream, ZipArchiveMode.Read);
-                    var logEntry = zipArchive.Entries.FirstOrDefault(e => e.Name.EndsWith(".xml", StringComparison.InvariantCultureIgnoreCase));
-                    if (logEntry == null)
-                        throw new InvalidOperationException("No zip entries that match the .xml criteria");
-
-                    using var zipStream = logEntry.Open();
-                    using var xmlReader = XmlReader.Create(zipStream, new XmlReaderSettings { Async = true });
-                    xmlReader.ReadToFollowing("PS3TDB");
-                    var version = xmlReader.GetAttribute("version");
-                    if (!DateTime.TryParseExact(version, "yyyyMMddHHmmss", CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal, out var timestamp))
-                        return;
-
-                    if (ScrapeStateProvider.IsFresh("PS3TDB", timestamp))
-                    {
-                        await ScrapeStateProvider.SetLastRunTimestampAsync("PS3TDB").ConfigureAwait(false);
-                        return;
-                    }
-
-                    while (!cancellationToken.IsCancellationRequested && xmlReader.ReadToFollowing("game"))
-                    {
-                        if (xmlReader.ReadToFollowing("id"))
-                        {
-                            var productId = (await xmlReader.ReadElementContentAsStringAsync().ConfigureAwait(false)).ToUpperInvariant();
-                            if (!ProductCodeLookup.ProductCode.IsMatch(productId))
-                                continue;
-
-                            string title = null;
-                            if (xmlReader.ReadToFollowing("locale") && xmlReader.ReadToFollowing("title"))
-                                title = await xmlReader.ReadElementContentAsStringAsync().ConfigureAwait(false);
-
-                            if (!string.IsNullOrEmpty(title))
-                            {
-                                using var db = new ThumbnailDb();
-                                var item = await db.Thumbnail.FirstOrDefaultAsync(t => t.ProductCode == productId, cancellationToken).ConfigureAwait(false);
-                                if (item == null)
-                                {
-                                    await db.Thumbnail.AddAsync(new Thumbnail {ProductCode = productId, Name = title}, cancellationToken).ConfigureAwait(false);
-                                    await db.SaveChangesAsync(cancellationToken).ConfigureAwait(false);
-                                }
-                                else
-                                {
-                                    if (item.Name != title && item.Timestamp == 0)
-                                    {
-                                        item.Name = title;
-                                        await db.SaveChangesAsync(cancellationToken).ConfigureAwait(false);
-                                    }
-                                }
-                            }
-                        }
-                    }
                     await ScrapeStateProvider.SetLastRunTimestampAsync("PS3TDB").ConfigureAwait(false);
+                    return;
                 }
+
+                while (!cancellationToken.IsCancellationRequested && xmlReader.ReadToFollowing("game"))
+                {
+                    if (!xmlReader.ReadToFollowing("id"))
+                        continue;
+                    
+                    var productId = (await xmlReader.ReadElementContentAsStringAsync().ConfigureAwait(false)).ToUpperInvariant();
+                    if (!ProductCodeLookup.ProductCode.IsMatch(productId))
+                        continue;
+
+                    string? title = null;
+                    if (xmlReader.ReadToFollowing("locale") && xmlReader.ReadToFollowing("title"))
+                        title = await xmlReader.ReadElementContentAsStringAsync().ConfigureAwait(false);
+
+                    if (string.IsNullOrEmpty(title))
+                        continue;
+
+                    await using var db = new ThumbnailDb();
+                    var item = await db.Thumbnail.FirstOrDefaultAsync(t => t.ProductCode == productId, cancellationToken).ConfigureAwait(false);
+                    if (item is null)
+                    {
+                        await db.Thumbnail.AddAsync(new Thumbnail {ProductCode = productId, Name = title}, cancellationToken).ConfigureAwait(false);
+                        await db.SaveChangesAsync(cancellationToken).ConfigureAwait(false);
+                    }
+                    else if (item.Name != title && item.Timestamp == 0)
+                    {
+                        item.Name = title;
+                        await db.SaveChangesAsync(cancellationToken).ConfigureAwait(false);
+                    }
+                }
+                await ScrapeStateProvider.SetLastRunTimestampAsync("PS3TDB").ConfigureAwait(false);
                 await ScrapeStateProvider.SetLastRunTimestampAsync(container).ConfigureAwait(false);
             }
             catch (Exception e)

CompatBot/Utils/AsciiColumn.cs

@@ -2,7 +2,7 @@
 {
     public sealed class AsciiColumn
     {
-        public AsciiColumn(string name = null, bool disabled = false, bool alignToRight = false, int maxWidth = 80)
+        public AsciiColumn(string? name = null, bool disabled = false, bool alignToRight = false, int maxWidth = 80)
         {
             Name = name;
             Disabled = disabled;
@@ -10,7 +10,7 @@
             MaxWidth = maxWidth;
         }
 
-        public string Name;
+        public string? Name;
         public bool Disabled;
         public bool AlignToRight;
         public int MaxWidth;

CompatBot/Utils/AsciiTable.cs

@@ -48,7 +48,7 @@ namespace CompatBot.Utils
             width = new int[columns.Length];
             for (var i = 0; i < columns.Length; i++)
             {
-                this.columns[i] = columns[i].Name;
+                this.columns[i] = columns[i].Name ?? "";
                 disabled[i] = columns[i].Disabled;
                 maxWidth[i] = columns[i].MaxWidth;
                 width[i] = columns[i].Name.GetVisibleLength();

CompatBot/Utils/CompatApiResultUtils.cs

@@ -31,7 +31,7 @@ namespace CompatBot.Utils
             return sortedList;
         }
 
-        public static double GetScore(string search, TitleInfo titleInfo)
+        public static double GetScore(string? search, TitleInfo titleInfo)
         {
             var score = Math.Max(
                 search.GetFuzzyCoefficientCached(titleInfo.Title),

CompatBot/Utils/Extensions/AutosplitResponseHelper.cs

@@ -10,29 +10,17 @@ namespace CompatBot.Utils
 {
     public static class AutosplitResponseHelper
     {
-        public static Task SendAutosplitMessageAsync(this CommandContext ctx, StringBuilder message, int blockSize = 2000, string blockEnd = "\n```", string blockStart = "```\n")
+        public static Task SendAutosplitMessageAsync(this CommandContext ctx, StringBuilder message, int blockSize = 2000, string? blockEnd = "\n```", string? blockStart = "```\n")
+            => ctx.Channel.SendAutosplitMessageAsync(message, blockSize, blockEnd, blockStart);
+
+        public static Task SendAutosplitMessageAsync(this CommandContext ctx, string message, int blockSize = 2000, string? blockEnd = "\n```", string? blockStart = "```\n")
+            => ctx.Channel.SendAutosplitMessageAsync(message, blockSize, blockEnd, blockStart);
+
+        public static async Task SendAutosplitMessageAsync(this DiscordChannel channel, StringBuilder message, int blockSize = 2000, string? blockEnd = "\n```", string? blockStart = "```\n")
+            => await SendAutosplitMessageAsync(channel, message.ToString(), blockSize, blockEnd, blockStart).ConfigureAwait(false);
+
+        public static async Task SendAutosplitMessageAsync(this DiscordChannel channel, string message, int blockSize = 2000, string? blockEnd = "\n```", string? blockStart = "```\n")
         {
-            return ctx.Channel.SendAutosplitMessageAsync(message, blockSize, blockEnd, blockStart);
-        }
-
-        public static Task SendAutosplitMessageAsync(this CommandContext ctx, string message, int blockSize = 2000, string blockEnd = "\n```", string blockStart = "```\n")
-        {
-            return ctx.Channel.SendAutosplitMessageAsync(message, blockSize, blockEnd, blockStart);
-        }
-
-        public static async Task SendAutosplitMessageAsync(this DiscordChannel channel, StringBuilder message, int blockSize = 2000, string blockEnd = "\n```", string blockStart = "```\n")
-        {
-            if (message == null)
-                throw new ArgumentNullException(nameof(message));
-
-            await SendAutosplitMessageAsync(channel, message.ToString(), blockSize, blockEnd, blockStart).ConfigureAwait(false);
-        }
-
-        public static async Task SendAutosplitMessageAsync(this DiscordChannel channel, string message, int blockSize = 2000, string blockEnd = "\n```", string blockStart = "```\n")
-        {
-            if (channel == null)
-                throw new ArgumentNullException(nameof(channel));
-
             if (string.IsNullOrEmpty(message))
                 return;
 

CompatBot/Utils/Extensions/AzureDevOpsClientExtensions.cs

@@ -17,18 +17,18 @@ namespace CompatBot.Utils.Extensions
 
         public class BuildInfo
         {
-            public string Commit;
-            public string WindowsFilename;
-            public string LinuxFilename;
-            public string WindowsBuildDownloadLink;
-            public string LinuxBuildDownloadLink;
+            public string? Commit;
+            public string? WindowsFilename;
+            public string? LinuxFilename;
+            public string? WindowsBuildDownloadLink;
+            public string? LinuxBuildDownloadLink;
             public DateTime? StartTime;
             public DateTime? FinishTime;
             public BuildStatus? Status;
             public BuildResult? Result { get; set; }
         }
 
-        public static async Task<List<BuildInfo>> GetMasterBuildsAsync(this BuildHttpClient azureDevOpsClient, string oldestMergeCommit, string newestMergeCommit, DateTime? oldestTimestamp, CancellationToken cancellationToken)
+        public static async Task<List<BuildInfo>?> GetMasterBuildsAsync(this BuildHttpClient? azureDevOpsClient, string? oldestMergeCommit, string? newestMergeCommit, DateTime? oldestTimestamp, CancellationToken cancellationToken)
         {
             if (azureDevOpsClient == null || string.IsNullOrEmpty(oldestMergeCommit) || string.IsNullOrEmpty(newestMergeCommit))
                 return null;
@@ -57,7 +57,7 @@ namespace CompatBot.Utils.Extensions
             return builds.Select(b => azureDevOpsClient.GetArtifactsInfoAsync(b.SourceVersion, b, cancellationToken).GetAwaiter().GetResult()).ToList();
         }
 
-        public static async Task<BuildInfo> GetMasterBuildInfoAsync(this BuildHttpClient azureDevOpsClient, string commit, DateTime? oldestTimestamp, CancellationToken cancellationToken)
+        public static async Task<BuildInfo?> GetMasterBuildInfoAsync(this BuildHttpClient? azureDevOpsClient, string? commit, DateTime? oldestTimestamp, CancellationToken cancellationToken)
         {
             if (azureDevOpsClient == null || string.IsNullOrEmpty(commit))
                 return null;
@@ -91,7 +91,7 @@ namespace CompatBot.Utils.Extensions
             return result;
         }
 
-        public static async Task<BuildInfo> GetPrBuildInfoAsync(this BuildHttpClient azureDevOpsClient, string commit, DateTime? oldestTimestamp, int pr, CancellationToken cancellationToken)
+        public static async Task<BuildInfo?> GetPrBuildInfoAsync(this BuildHttpClient? azureDevOpsClient, string? commit, DateTime? oldestTimestamp, int pr, CancellationToken cancellationToken)
         {
             if (azureDevOpsClient == null || string.IsNullOrEmpty(commit))
                 return null;
@@ -127,9 +127,6 @@ namespace CompatBot.Utils.Extensions
 
         public static async Task<BuildInfo> GetArtifactsInfoAsync(this BuildHttpClient azureDevOpsClient, string commit, Build build, CancellationToken cancellationToken)
         {
-            if (azureDevOpsClient == null)
-                return null;
-
             var result = new BuildInfo
             {
                 Commit = commit,
@@ -149,7 +146,7 @@ namespace CompatBot.Utils.Extensions
                     try
                     {
                         using var httpClient = HttpClientFactory.Create();
-                        using var stream = await httpClient.GetStreamAsync(winDownloadUrl).ConfigureAwait(false);
+                        await using var stream = await httpClient.GetStreamAsync(winDownloadUrl, cancellationToken).ConfigureAwait(false);
                         using var zipStream = ReaderFactory.Open(stream);
                         while (zipStream.MoveToNextEntry() && !cancellationToken.IsCancellationRequested)
                         {
@@ -176,7 +173,7 @@ namespace CompatBot.Utils.Extensions
                     try
                     {
                         using var httpClient = HttpClientFactory.Create();
-                        using var stream = await httpClient.GetStreamAsync(linDownloadUrl).ConfigureAwait(false);
+                        await using var stream = await httpClient.GetStreamAsync(linDownloadUrl, cancellationToken).ConfigureAwait(false);
                         using var zipStream = ReaderFactory.Open(stream);
                         while (zipStream.MoveToNextEntry() && !cancellationToken.IsCancellationRequested)
                         {

CompatBot/Utils/Extensions/DiscordClientExtensions.cs

@@ -14,37 +14,33 @@ namespace CompatBot.Utils
 {
     public static class DiscordClientExtensions
     {
-        public static DiscordMember GetMember(this DiscordClient client, DiscordGuild guild, ulong userId)
+        public static DiscordMember? GetMember(this DiscordClient client, DiscordGuild? guild, ulong userId)
         {
-            if (guild == null)
+            if (guild is null)
                 return GetMember(client, userId);
 
             return GetMember(client, guild.Id, userId);
         }
 
-        public static DiscordMember GetMember(this DiscordClient client, ulong guildId, ulong userId)
-        {
-            return (from g in client.Guilds
+        public static DiscordMember? GetMember(this DiscordClient client, ulong guildId, ulong userId)
+            => (from g in client.Guilds
                     where g.Key == guildId
                     from u in g.Value.Members.Values
                     where u.Id == userId
                     select u
                 ).FirstOrDefault();
-        }
 
-        public static DiscordMember GetMember(this DiscordClient client, ulong guildId, DiscordUser user) => GetMember(client, guildId, user.Id);
-        public static DiscordMember GetMember(this DiscordClient client, DiscordGuild guild, DiscordUser user) => GetMember(client, guild, user.Id);
+        public static DiscordMember? GetMember(this DiscordClient client, ulong guildId, DiscordUser user) => GetMember(client, guildId, user.Id);
+        public static DiscordMember? GetMember(this DiscordClient client, DiscordGuild? guild, DiscordUser user) => GetMember(client, guild, user.Id);
 
-        public static DiscordMember GetMember(this DiscordClient client, ulong userId)
-        {
-            return (from g in client.Guilds
+        public static DiscordMember? GetMember(this DiscordClient client, ulong userId)
+            => (from g in client.Guilds
                     from u in g.Value.Members.Values
                     where u.Id == userId
                     select u
                 ).FirstOrDefault();
-        }
 
-        public static DiscordMember GetMember(this DiscordClient client, DiscordUser user) => GetMember(client, user.Id);
+        public static DiscordMember? GetMember(this DiscordClient client, DiscordUser user) => GetMember(client, user.Id);
 
         public static async Task<string> GetUserNameAsync(this DiscordClient client, DiscordChannel channel, ulong userId, bool? forDmPurposes = null, string defaultName = "Unknown user")
         {
@@ -74,7 +70,7 @@ namespace CompatBot.Utils
             }
         }
 
-        public static async Task ReactWithAsync(this DiscordMessage message, DiscordEmoji emoji, string fallbackMessage = null, bool? showBoth = null)
+        public static async Task ReactWithAsync(this DiscordMessage message, DiscordEmoji emoji, string? fallbackMessage = null, bool? showBoth = null)
         {
             try
             {
@@ -96,7 +92,7 @@ namespace CompatBot.Utils
             return RemoveReactionAsync(ctx.Message, emoji);
         }
 
-        public static Task ReactWithAsync(this CommandContext ctx, DiscordEmoji emoji, string fallbackMessage = null, bool? showBoth = null)
+        public static Task ReactWithAsync(this CommandContext ctx, DiscordEmoji emoji, string? fallbackMessage = null, bool? showBoth = null)
         {
             return ReactWithAsync(ctx.Message, emoji, fallbackMessage, showBoth ?? (ctx.Prefix == Config.AutoRemoveCommandPrefix));
         }
@@ -104,17 +100,17 @@ namespace CompatBot.Utils
         public static async Task<IReadOnlyCollection<DiscordMessage>> GetMessagesBeforeAsync(this DiscordChannel channel, ulong beforeMessageId, int limit = 100, DateTime? timeLimit = null)
         {
             if (timeLimit > DateTime.UtcNow)
-                throw new ArgumentException(nameof(timeLimit));
+                throw new ArgumentException("Time limit can't be set in the future", nameof(timeLimit));
 
             var afterTime = timeLimit ?? DateTime.UtcNow.AddSeconds(-30);
             var messages = await channel.GetMessagesBeforeCachedAsync(beforeMessageId, limit).ConfigureAwait(false);
             return messages.TakeWhile(m => m.CreationTimestamp > afterTime).ToList().AsReadOnly();
         }
 
-        public static async Task<DiscordMessage> ReportAsync(this DiscordClient client, string infraction, DiscordMessage message, string trigger, string context, ReportSeverity severity, string actionList = null)
+        public static async Task<DiscordMessage?> ReportAsync(this DiscordClient client, string infraction, DiscordMessage message, string trigger, string? context, ReportSeverity severity, string? actionList = null)
         {
             var logChannel = await client.GetChannelAsync(Config.BotLogId).ConfigureAwait(false);
-            if (logChannel == null)
+            if (logChannel is null)
                 return null;
 
             var embedBuilder = MakeReportTemplate(client, infraction, message, severity, actionList);
@@ -134,13 +130,11 @@ namespace CompatBot.Utils
             {
                 if (conents?.Count > 0)
                     foreach (var f in conents.Values)
-#pragma warning disable VSTHRD103
-                        f.Dispose();
-#pragma warning restore VSTHRD103
+                        await f.DisposeAsync();
             }
         }
 
-        public static async Task<DiscordMessage> ReportAsync(this DiscordClient client, string infraction, DiscordMessage message, IEnumerable<DiscordMember> reporters, string comment, ReportSeverity severity)
+        public static async Task<DiscordMessage> ReportAsync(this DiscordClient client, string infraction, DiscordMessage message, IEnumerable<DiscordMember> reporters, string? comment, ReportSeverity severity)
         {
             var getLogChannelTask = client.GetChannelAsync(Config.BotLogId);
             var embedBuilder = MakeReportTemplate(client, infraction, message, severity);
@@ -152,7 +146,7 @@ namespace CompatBot.Utils
             return await logChannel.SendMessageAsync(embed: embedBuilder.Build(), mentions: Config.AllowedMentions.Nothing).ConfigureAwait(false);
         }
 
-        public static async Task<DiscordMessage> ReportAsync(this DiscordClient client, string infraction, string description, ICollection<DiscordMember> potentialVictims, ReportSeverity severity)
+        public static async Task<DiscordMessage> ReportAsync(this DiscordClient client, string infraction, string description, ICollection<DiscordMember>? potentialVictims, ReportSeverity severity)
         {
             var result = new DiscordEmbedBuilder
             {
@@ -167,23 +161,15 @@ namespace CompatBot.Utils
         }
 
         public static string GetMentionWithNickname(this DiscordMember member)
+            => string.IsNullOrEmpty(member.Nickname) ? $"<@{member.Id}> (`{member.Username.Sanitize()}#{member.Discriminator}`)" : $"<@{member.Id}> (`{member.Username.Sanitize()}#{member.Discriminator}`, shown as `{member.Nickname.Sanitize()}`)";
+
+        public static string GetUsernameWithNickname(this DiscordUser user, DiscordClient client, DiscordGuild? guild = null)
         {
-            if (member == null)
-                return null;
-
-            return string.IsNullOrEmpty(member.Nickname) ? $"<@{member.Id}> (`{member.Username.Sanitize()}#{member.Discriminator}`)" : $"<@{member.Id}> (`{member.Username.Sanitize()}#{member.Discriminator}`, shown as `{member.Nickname.Sanitize()}`)";
-        }
-
-        public static string GetUsernameWithNickname(this DiscordUser user, DiscordClient client, DiscordGuild guild = null)
-        {
-            if (user == null)
-                return null;
-
             return client.GetMember(guild, user).GetUsernameWithNickname()
-                ?? $"`{user.Username.Sanitize()}#{user.Discriminator}`";
+                   ?? $"`{user.Username.Sanitize()}#{user.Discriminator}`";
         }
 
-        public static string GetUsernameWithNickname(this DiscordMember member)
+        public static string? GetUsernameWithNickname(this DiscordMember? member)
         {
             if (member == null)
                 return null;
@@ -191,12 +177,10 @@ namespace CompatBot.Utils
             return string.IsNullOrEmpty(member.Nickname) ? $"`{member.Username.Sanitize()}#{member.Discriminator}`" : $"`{member.Username.Sanitize()}#{member.Discriminator}` (shown as `{member.Nickname.Sanitize()}`)";
         }
 
-        public static DiscordEmoji GetEmoji(this DiscordClient client, string emojiName, string fallbackEmoji = null)
-        {
-            return GetEmoji(client, emojiName, fallbackEmoji == null ? null : DiscordEmoji.FromUnicode(fallbackEmoji));
-        }
+        public static DiscordEmoji? GetEmoji(this DiscordClient client, string? emojiName, string? fallbackEmoji = null)
+            => GetEmoji(client, emojiName, fallbackEmoji == null ? null : DiscordEmoji.FromUnicode(fallbackEmoji));
 
-        public static DiscordEmoji GetEmoji(this DiscordClient client, string emojiName, DiscordEmoji fallbackEmoji)
+        public static DiscordEmoji? GetEmoji(this DiscordClient client, string? emojiName, DiscordEmoji? fallbackEmoji)
         {
             if (string.IsNullOrEmpty(emojiName))
                 return fallbackEmoji;
@@ -215,15 +199,14 @@ namespace CompatBot.Utils
             }
         }
 
-        public static Task SendMessageAsync(this DiscordChannel channel, string message, byte[] attachment, string filename)
+        public static Task SendMessageAsync(this DiscordChannel channel, string message, byte[]? attachment, string? filename)
         {
             if (!string.IsNullOrEmpty(filename) && attachment?.Length > 0)
                 return channel.SendFileAsync(filename, new MemoryStream(attachment), message);
-            else
-                return channel.SendMessageAsync(message);
+            return channel.SendMessageAsync(message);
         }
 
-        private static DiscordEmbedBuilder MakeReportTemplate(DiscordClient client, string infraction, DiscordMessage message, ReportSeverity severity, string actionList = null)
+        private static DiscordEmbedBuilder MakeReportTemplate(DiscordClient client, string infraction, DiscordMessage message, ReportSeverity severity, string? actionList = null)
         {
             var content = message.Content;
             if (message.Channel.IsPrivate)
@@ -248,7 +231,7 @@ namespace CompatBot.Utils
 
             if (string.IsNullOrEmpty(content))
                 content = "🤔 something fishy is going on here, there was no message or attachment";
-            DiscordMember author = null;
+            DiscordMember? author = null;
             try
             {
                 author = client.GetMember(message.Author);
@@ -261,7 +244,7 @@ namespace CompatBot.Utils
                 {
                     Title = infraction,
                     Color = GetColor(severity),
-                }.AddField("Violator", author == null ? message.Author.Mention : GetMentionWithNickname(author), true)
+                }.AddField("Violator", author is null ? message.Author.Mention : GetMentionWithNickname(author), true)
                 .AddField("Channel",  message.Channel.IsPrivate ? "Bot's DM" : message.Channel.Mention, true)
                 //.AddField("Time (UTC)", message.CreationTimestamp.ToString("yyyy-MM-dd HH:mm:ss"), true)
                 .AddField("Content of the offending item", content.Trim(EmbedPager.MaxFieldLength));

CompatBot/Utils/Extensions/DiscordMessageExtensions.cs

@@ -11,8 +11,9 @@ namespace CompatBot.Utils
 {
     public static class DiscordMessageExtensions
     {
-        public static Task<DiscordMessage> UpdateOrCreateMessageAsync(this DiscordMessage message, DiscordChannel channel, string content = null, bool tts = false, DiscordEmbed embed = null)
+        public static Task<DiscordMessage> UpdateOrCreateMessageAsync(this DiscordMessage? message, DiscordChannel channel, string? content = null, bool tts = false, DiscordEmbed? embed = null)
         {
+            Exception? lastException = null;
             for (var i = 0; i<3; i++)
                 try
                 {
@@ -22,44 +23,43 @@ namespace CompatBot.Utils
                 }
                 catch (Exception e)
                 {
+                    lastException = e;
                     if (i == 2)
                         Config.Log.Error(e);
                     else
                         Task.Delay(100).ConfigureAwait(false).GetAwaiter().GetResult();
                 }
-            return Task.FromResult((DiscordMessage)null);
+            throw lastException ?? new InvalidOperationException("Something gone horribly wrong");
         }
 
-        public static async Task<(Dictionary<string, Stream> attachmentContent, List<string> failedFilenames)> DownloadAttachmentsAsync(this DiscordMessage msg)
+        public static async Task<(Dictionary<string, Stream>? attachmentContent, List<string>? failedFilenames)> DownloadAttachmentsAsync(this DiscordMessage msg)
         {
-            Dictionary<string, Stream> attachmentContent = null;
-            List<string> attachmentFilenames = null;
-            if (msg.Attachments.Any())
-            {
-                attachmentContent = new Dictionary<string, Stream>(msg.Attachments.Count);
-                attachmentFilenames = new List<string>();
-                using var httpClient = HttpClientFactory.Create(new CompressionMessageHandler());
-                foreach (var att in msg.Attachments)
-                {
-                    if (att.FileSize > Config.AttachmentSizeLimit)
-                    {
-                        attachmentFilenames.Add(att.FileName);
-                        continue;
-                    }
+            if (msg.Attachments.Count == 0)
+                return (null, null);
 
-                    try
-                    {
-                        using var sourceStream = await httpClient.GetStreamAsync(att.Url).ConfigureAwait(false);
-                        var fileStream = new FileStream(Path.GetTempFileName(), FileMode.Create, FileAccess.ReadWrite, FileShare.Read, 16384, FileOptions.Asynchronous | FileOptions.RandomAccess | FileOptions.DeleteOnClose);
-                        await sourceStream.CopyToAsync(fileStream, 16384, Config.Cts.Token).ConfigureAwait(false);
-                        fileStream.Seek(0, SeekOrigin.Begin);
-                        attachmentContent[att.FileName] = fileStream;
-                    }
-                    catch (Exception ex)
-                    {
-                        Config.Log.Warn(ex, $"Failed to download attachment {att.FileName} from deleted message {msg.JumpLink}");
-                        attachmentFilenames.Add(att.FileName);
-                    }
+            var attachmentContent = new Dictionary<string, Stream>(msg.Attachments.Count);
+            var attachmentFilenames = new List<string>();
+            using var httpClient = HttpClientFactory.Create(new CompressionMessageHandler());
+            foreach (var att in msg.Attachments)
+            {
+                if (att.FileSize > Config.AttachmentSizeLimit)
+                {
+                    attachmentFilenames.Add(att.FileName);
+                    continue;
+                }
+
+                try
+                {
+                    await using var sourceStream = await httpClient.GetStreamAsync(att.Url).ConfigureAwait(false);
+                    var fileStream = new FileStream(Path.GetTempFileName(), FileMode.Create, FileAccess.ReadWrite, FileShare.Read, 16384, FileOptions.Asynchronous | FileOptions.RandomAccess | FileOptions.DeleteOnClose);
+                    await sourceStream.CopyToAsync(fileStream, 16384, Config.Cts.Token).ConfigureAwait(false);
+                    fileStream.Seek(0, SeekOrigin.Begin);
+                    attachmentContent[att.FileName] = fileStream;
+                }
+                catch (Exception ex)
+                {
+                    Config.Log.Warn(ex, $"Failed to download attachment {att.FileName} from deleted message {msg.JumpLink}");
+                    attachmentFilenames.Add(att.FileName);
                 }
             }
             return (attachmentContent: attachmentContent, failedFilenames: attachmentFilenames);

CompatBot/Utils/Extensions/InteractivityExtensions.cs

@@ -11,31 +11,29 @@ namespace CompatBot.Utils
 {
     public static class InteractivityExtensions
     {
-        public static Task<(DiscordMessage message, DiscordMessage text, MessageReactionAddEventArgs reaction)> WaitForMessageOrReactionAsync(
+        public static Task<(DiscordMessage? message, DiscordMessage? text, MessageReactionAddEventArgs? reaction)> WaitForMessageOrReactionAsync(
             this InteractivityExtension interactivity,
             DiscordMessage message,
             DiscordUser user,
             params DiscordEmoji[] reactions)
             => WaitForMessageOrReactionAsync(interactivity, message, user, null, reactions);
 
-        public static async Task<(DiscordMessage message, DiscordMessage text, MessageReactionAddEventArgs reaction)> WaitForMessageOrReactionAsync(
+        public static async Task<(DiscordMessage? message, DiscordMessage? text, MessageReactionAddEventArgs? reaction)> WaitForMessageOrReactionAsync(
             this InteractivityExtension interactivity,
             DiscordMessage message,
             DiscordUser user,
             TimeSpan? timeout,
-            params DiscordEmoji[] reactions)
+            params DiscordEmoji?[] reactions)
         {
-            if (message == null)
-                throw new ArgumentNullException(nameof(message));
-
             if (reactions.Length == 0)
                 throw new ArgumentException("At least one reaction must be specified", nameof(reactions));
 
+            DiscordMessage? result = message;
             try
             {
                 reactions = reactions.Where(r => r != null).ToArray();
                 foreach (var emoji in reactions)
-                    await message.ReactWithAsync(emoji).ConfigureAwait(false);
+                    await message.ReactWithAsync(emoji!).ConfigureAwait(false);
                 var expectedChannel = message.Channel;
                 var waitTextResponseTask = interactivity.WaitForMessageAsync(m => m.Author == user && m.Channel == expectedChannel && !string.IsNullOrEmpty(m.Content), timeout);
                 var waitReactionResponse = interactivity.WaitForReactionAsync(arg => reactions.Contains(arg.Emoji), message, user, timeout);
@@ -50,10 +48,10 @@ namespace CompatBot.Utils
                 catch
                 {
                     await message.DeleteAsync().ConfigureAwait(false);
-                    message = null;
+                    result = null;
                 }
-                DiscordMessage text = null;
-                MessageReactionAddEventArgs reaction = null;
+                DiscordMessage? text = null;
+                MessageReactionAddEventArgs? reaction = null;
                 if (waitTextResponseTask.IsCompletedSuccessfully)
                     text = (await waitTextResponseTask).Result;
                 if (waitReactionResponse.IsCompletedSuccessfully)
@@ -65,12 +63,12 @@ namespace CompatBot.Utils
                         await text.DeleteAsync().ConfigureAwait(false);
                     }
                     catch {}
-                return (message, text, reaction);
+                return (result, text, reaction);
             }
             catch (Exception e)
             {
                 Config.Log.Warn(e, "Failed to get interactive reaction");
-                return (message, null, null);
+                return (result, null, null);
             }
         }
     }

CompatBot/Utils/Extensions/MemoryCacheExtensions.cs

@@ -10,42 +10,37 @@ namespace CompatBot.Utils
     {
         public static List<T> GetCacheKeys<T>(this MemoryCache memoryCache)
         {
-            if (memoryCache == null)
-                return null;
-
             var field = memoryCache.GetType()
                 .GetFields(BindingFlags.NonPublic | BindingFlags.Instance)
                 .FirstOrDefault(fi => fi.Name == "_entries");
 
-            if (field == null)
+            if (field is null)
             {
                 Config.Log.Error($"Looks like {nameof(MemoryCache)} internals have changed");
-                return new List<T>(0);
+                return new List<T>();
             }
 
-            var value = (IDictionary)field.GetValue(memoryCache);
-            return value.Keys.OfType<T>().ToList();
+            var value = (IDictionary?)field.GetValue(memoryCache);
+            return value?.Keys.OfType<T>().ToList() ?? new List<T>();
         }
 
-        public static Dictionary<TKey, ICacheEntry> GetCacheEntries<TKey>(this MemoryCache memoryCache)
+        public static Dictionary<TKey, ICacheEntry?> GetCacheEntries<TKey>(this MemoryCache memoryCache)
+            where TKey: notnull
         {
-            if (memoryCache == null)
-                return null;
-
             var field = memoryCache.GetType()
                 .GetFields(BindingFlags.NonPublic | BindingFlags.Instance)
                 .FirstOrDefault(fi => fi.Name == "_entries");
 
-            if (field == null)
+            var cacheEntries = (IDictionary?)field?.GetValue(memoryCache);
+            if (cacheEntries is null)
             {
                 Config.Log.Error($"Looks like {nameof(MemoryCache)} internals have changed");
-                return new Dictionary<TKey, ICacheEntry>(0);
+                return new Dictionary<TKey, ICacheEntry?>(0);
             }
 
-            var cacheEntries = (IDictionary)field.GetValue(memoryCache);
-            var result = new Dictionary<TKey, ICacheEntry>(cacheEntries.Count);
+            var result = new Dictionary<TKey, ICacheEntry?>(cacheEntries.Count);
             foreach (DictionaryEntry e in cacheEntries)
-                result.Add((TKey)e.Key, (ICacheEntry)e.Value);
+                result.Add((TKey)e.Key, (ICacheEntry?)e.Value);
             return result;
         }
     }

CompatBot/Utils/Extensions/StringUtils.cs

@@ -41,7 +41,7 @@ namespace CompatBot.Utils
 
         public static string StripMarks(this string str)
         {
-            return str?.Replace("(R)", " ", StringComparison.InvariantCultureIgnoreCase)
+            return str.Replace("(R)", " ", StringComparison.InvariantCultureIgnoreCase)
                 .Replace("®", " ")
                 .Replace("(TM)", " ", StringComparison.InvariantCultureIgnoreCase)
                 .Replace("™", " ")
@@ -52,7 +52,7 @@ namespace CompatBot.Utils
 
         public static string StripQuotes(this string str)
         {
-            if (str == null || str.Length < 2)
+            if (str.Length < 2)
                 return str;
 
             if (str.StartsWith('"') && str.EndsWith('"'))
@@ -117,7 +117,7 @@ namespace CompatBot.Utils
             return CreateTrimmedString(str, start, end);
         }
 
-        public static string AsString(this ReadOnlySequence<byte> buffer, Encoding encoding = null)
+        public static string AsString(this ReadOnlySequence<byte> buffer, Encoding? encoding = null)
         {
             encoding ??= Latin8BitEncoding;
             if (buffer.IsSingleSegment)
@@ -135,9 +135,7 @@ namespace CompatBot.Utils
         }
 
         public static string ToUtf8(this string str)
-        {
-            return Utf8.GetString(Latin8BitEncoding.GetBytes(str));
-        }
+            => Utf8.GetString(Latin8BitEncoding.GetBytes(str));
 
         public static string ToLatin8BitEncoding(this string str)
         {
@@ -154,11 +152,12 @@ namespace CompatBot.Utils
 
         public static string GetSuffix(long num) => num == 1 ? "" : "s";
 
-        public static string FixSpaces(this string text) => text?.Replace(" ", " " + InvisibleSpacer)
-            .Replace("`", InvisibleSpacer + "`")
-            .Replace(Environment.NewLine, "\n");
+        public static string FixSpaces(this string text)
+            => text.Replace(" ", " " + InvisibleSpacer)
+                .Replace("`", InvisibleSpacer + "`")
+                .Replace(Environment.NewLine, "\n");
 
-        public static int GetVisibleLength(this string s)
+        public static int GetVisibleLength(this string? s)
         {
             if (string.IsNullOrEmpty(s))
                 return 0;
@@ -217,9 +216,6 @@ namespace CompatBot.Utils
 
         public static string TrimVisible(this string s, int maxLength)
         {
-            if (string.IsNullOrEmpty(s))
-                return s;
-
             if (maxLength < 1)
                 throw new ArgumentException("Max length can't be less than 1", nameof(maxLength));
 
@@ -238,12 +234,11 @@ namespace CompatBot.Utils
 
                 c++;
             }
-            return result.Append("…").ToString();
+            return result.Append('…').ToString();
         }
 
         public static string PadLeftVisible(this string s, int totalWidth, char padding = ' ')
         {
-            s ??= "";
             var valueWidth = s.GetVisibleLength();
             var diff = s.Length - valueWidth;
             totalWidth += diff;
@@ -252,7 +247,6 @@ namespace CompatBot.Utils
 
         public static string PadRightVisible(this string s, int totalWidth, char padding = ' ')
         {
-            s ??= "";
             var valueWidth = s.GetVisibleLength();
             var diff = s.Length - valueWidth;
             totalWidth += diff;
@@ -278,7 +272,7 @@ namespace CompatBot.Utils
         public static string GetMoons(decimal? stars, bool haveFun = true)
         {
             if (!stars.HasValue)
-                return null;
+                return "";
 
             var fullStars = (int)stars;
             var halfStar = (int)Math.Round((stars.Value - fullStars)*4, MidpointRounding.ToEven);
@@ -314,7 +308,7 @@ namespace CompatBot.Utils
         public static string GetStars(decimal? stars)
         {
             if (!stars.HasValue)
-                return null;
+                return "";
 
             var fullStars = (int)Math.Round(stars.Value, MidpointRounding.ToEven);
             var noStars = 5 - fullStars;
@@ -355,7 +349,7 @@ namespace CompatBot.Utils
             return result;
         }
 
-        internal static double GetFuzzyCoefficientCached(this string strA, string strB)
+        internal static double GetFuzzyCoefficientCached(this string? strA, string? strB)
         {
             strA = strA?.ToLowerInvariant() ?? "";
             strB = strB?.ToLowerInvariant() ?? "";
@@ -396,8 +390,8 @@ namespace CompatBot.Utils
 
         private class FuzzyCacheValue
         {
-            public string StrA;
-            public string StrB;
+            public string? StrA;
+            public string? StrB;
             public double Coefficient;
         }
     }

CompatBot/Utils/FixedLengthBuffer.cs

@@ -1,17 +1,19 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 
 namespace CompatBot.Utils
 {
     internal class FixedLengthBuffer<TKey, TValue>: IList<TValue>
+        where TKey: notnull
     {
         internal readonly object syncObj = new object();
         
         public FixedLengthBuffer(Func<TValue, TKey> keyGenerator)
         {
-            makeKey = keyGenerator ?? throw new ArgumentNullException(nameof(keyGenerator));
+            makeKey = keyGenerator;
         }
 
         public FixedLengthBuffer<TKey, TValue> CloneShallow()
@@ -19,8 +21,8 @@ namespace CompatBot.Utils
             var result = new FixedLengthBuffer<TKey, TValue>(makeKey);
             foreach (var key in keyList)
                 result.keyList.Add(key);
-            foreach (var kvp in lookup)
-                result.lookup[kvp.Key] = kvp.Value;
+            foreach (var (key, value) in lookup)
+                result.lookup[key] = value;
             return result;
         }
 
@@ -29,7 +31,7 @@ namespace CompatBot.Utils
 
         public void Add(TValue item)
         {
-            TKey key = makeKey(item);
+            var key = makeKey(item);
             if (!lookup.ContainsKey(key))
                 keyList.Add(key);
             lookup[key] = item;
@@ -72,7 +74,7 @@ namespace CompatBot.Utils
         public TValue Evict(TKey key)
         {
             if (!lookup.TryGetValue(key, out var result))
-                return default;
+                return result;
             
             lookup.Remove(key);
             keyList.Remove(key);

CompatBot/Utils/ResultFormatters/LogParserResultFormatter.cs

@@ -316,7 +316,7 @@ namespace CompatBot.Utils.ResultFormatters
                 items["gpu_info"] = items["driver_manuf"];
             if (!string.IsNullOrEmpty(items["gpu_info"]))
             {
-                items["gpu_info"] = items["gpu_info"].StripMarks();
+                items["gpu_info"] = items["gpu_info"]?.StripMarks();
                 items["driver_version_info"] = GetVulkanDriverVersion(items["vulkan_initialized_device"], multiItems["vulkan_found_device"]) ??
                                                GetVulkanDriverVersion(items["gpu_info"], multiItems["vulkan_found_device"]) ??
                                                GetOpenglDriverVersion(items["gpu_info"], items["driver_version_new"] ?? items["driver_version"]) ??
@@ -389,10 +389,10 @@ namespace CompatBot.Utils.ResultFormatters
                 var interpreter = sm.Contains("interpreter", StringComparison.InvariantCultureIgnoreCase);
                 items["shader_mode"] = (async, recompiler, interpreter) switch
                 {
-                    (true, true, false)  => "Async",
-                    (true, _, true)      => "Async+Interpreter",
+                    ( true, true, false) => "Async",
+                    ( true,    _,  true) => "Async+Interpreter",
                     (false, true, false) => "Recompiler only",
-                    (false, _, true)     => "Interpreter only",
+                    (false,    _,  true) => "Interpreter only",
                     _                    => items["shader_mode"],
                 };
             }
@@ -401,7 +401,7 @@ namespace CompatBot.Utils.ResultFormatters
             else
                 items["shader_mode"] = "Recompiler only";
 
-            static string reformatDecoder(string dec)
+            static string? reformatDecoder(string? dec)
             {
                 if (string.IsNullOrEmpty(dec))
                     return dec;
@@ -418,7 +418,7 @@ namespace CompatBot.Utils.ResultFormatters
                 items["os_type"] = "Windows";
             else if (items["lin_path"] != null)
                 items["os_type"] = "Linux";
-            if (items["os_type"] == "Windows" && GetWindowsVersion((items["driver_version_new"] ?? items["driver_version"])) is string winVersion)
+            if (items["os_type"] == "Windows" && GetWindowsVersion(items["driver_version_new"] ?? items["driver_version"]) is string winVersion)
                 items["os_windows_version"] = winVersion;
             if (items["library_list"] is string libs)
             {
@@ -451,7 +451,7 @@ namespace CompatBot.Utils.ResultFormatters
                     value = EnabledMark;
                 else if ("false".Equals(value, StringComparison.CurrentCultureIgnoreCase))
                     value = DisabledMark;
-                items[key] = value.Sanitize(false);
+                items[key] = value?.Sanitize(false);
             }
         }
 
@@ -468,7 +468,7 @@ namespace CompatBot.Utils.ResultFormatters
             }
         }
 
-        private static async Task<UpdateInfo> CheckForUpdateAsync(NameValueCollection items)
+        private static async Task<UpdateInfo?> CheckForUpdateAsync(NameValueCollection items)
         {
             if (string.IsNullOrEmpty(items["build_and_specs"]))
                 return null;
@@ -490,17 +490,20 @@ namespace CompatBot.Utils.ResultFormatters
             return null;
         }
 
-        private static bool VersionIsTooOld(NameValueCollection items, Match update, UpdateInfo updateInfo)
+        private static bool VersionIsTooOld(NameValueCollection items, Match update, UpdateInfo? updateInfo)
         {
-            if ((updateInfo.GetUpdateDelta() is TimeSpan updateTimeDelta) && (updateTimeDelta < Config.BuildTimeDifferenceForOutdatedBuildsInDays))
+            if (updateInfo.GetUpdateDelta() is TimeSpan updateTimeDelta
+                && updateTimeDelta < Config.BuildTimeDifferenceForOutdatedBuildsInDays)
                 return false;
 
-            if (Version.TryParse(items["build_version"], out var logVersion) && Version.TryParse(update.Groups["version"].Value, out var updateVersion))
+            if (Version.TryParse(items["build_version"], out var logVersion)
+                && Version.TryParse(update.Groups["version"].Value, out var updateVersion))
             {
                 if (logVersion < updateVersion)
                     return true;
 
-                if (int.TryParse(items["build_number"], out var logBuild) && int.TryParse(update.Groups["build"].Value, out var updateBuild))
+                if (int.TryParse(items["build_number"], out var logBuild)
+                    && int.TryParse(update.Groups["build"].Value, out var updateBuild))
                 {
                     if (logBuild + Config.BuildNumberDifferenceForOutdatedBuilds < updateBuild)
                         return true;
@@ -510,7 +513,7 @@ namespace CompatBot.Utils.ResultFormatters
             return !SameCommits(items["build_commit"], update.Groups["commit"].Value);
         }
 
-        private static bool SameCommits(string commitA, string commitB)
+        private static bool SameCommits(string? commitA, string? commitB)
         {
             if (string.IsNullOrEmpty(commitA) && string.IsNullOrEmpty(commitB))
                 return true;
@@ -522,20 +525,21 @@ namespace CompatBot.Utils.ResultFormatters
             return commitA[..len] == commitB[..len];
         }
 
-        private static string GetOpenglDriverVersion(string gpuInfo, string version)
+        private static string? GetOpenglDriverVersion(string? gpuInfo, string? version)
         {
             if (string.IsNullOrEmpty(version))
                 return null;
 
-            if (gpuInfo.Contains("Radeon", StringComparison.InvariantCultureIgnoreCase) ||
-                gpuInfo.Contains("AMD", StringComparison.InvariantCultureIgnoreCase) ||
-                gpuInfo.Contains("ATI ", StringComparison.InvariantCultureIgnoreCase))
+            gpuInfo ??= "";
+            if (gpuInfo.Contains("Radeon", StringComparison.InvariantCultureIgnoreCase)
+                || gpuInfo.Contains("AMD", StringComparison.InvariantCultureIgnoreCase)
+                || gpuInfo.Contains("ATI ", StringComparison.InvariantCultureIgnoreCase))
                 return AmdDriverVersionProvider.GetFromOpenglAsync(version).ConfigureAwait(false).GetAwaiter().GetResult();
 
             return version;
         }
 
-        private static string GetVulkanDriverVersion(string gpu, UniqueList<string> foundDevices)
+        private static string? GetVulkanDriverVersion(string? gpu, UniqueList<string> foundDevices)
         {
             if (string.IsNullOrEmpty(gpu) || !foundDevices.Any())
                 return null;
@@ -585,11 +589,12 @@ namespace CompatBot.Utils.ResultFormatters
             return result;
         }
 
-        private static string GetVulkanDriverVersionRaw(string gpuInfo, string version)
+        private static string? GetVulkanDriverVersionRaw(string? gpuInfo, string? version)
         {
             if (string.IsNullOrEmpty(version))
                 return null;
 
+            gpuInfo ??= "";
             var ver = int.Parse(version);
             if (IsAmd(gpuInfo))
             {
@@ -621,7 +626,7 @@ namespace CompatBot.Utils.ResultFormatters
             }
         }
 
-        private static string GetWindowsVersion(string driverVersionString)
+        private static string? GetWindowsVersion(string? driverVersionString)
         {
             // see https://docs.microsoft.com/en-us/windows-hardware/drivers/display/wddm-2-1-features#driver-versioning
             if (string.IsNullOrEmpty(driverVersionString) || !Version.TryParse(driverVersionString, out var driverVer))
@@ -651,7 +656,7 @@ namespace CompatBot.Utils.ResultFormatters
             };
         }
 
-        private static string GetWindowsVersion(Version windowsVersion) =>
+        private static string? GetWindowsVersion(Version windowsVersion) =>
             windowsVersion.Major switch
             {
                 5 => windowsVersion.Minor switch
@@ -747,9 +752,9 @@ namespace CompatBot.Utils.ResultFormatters
             return $"{microseconds / 1_000_000.0:0.##} s";
         }
 
-        private static List<string> SortLines(List<string> notes, DiscordEmoji piracyEmoji = null)
+        private static List<string> SortLines(List<string> notes, DiscordEmoji? piracyEmoji = null)
         {
-            if (notes == null || notes.Count < 2)
+            if (notes.Count < 2)
                 return notes;
 
             var priorityList = new List<string>(EmojiPriority);
@@ -795,36 +800,33 @@ namespace CompatBot.Utils.ResultFormatters
             return new HashSet<string>(hashList.Split(Environment.NewLine), StringComparer.InvariantCultureIgnoreCase);
         }
 
-        internal static DiscordEmbedBuilder AddAuthor(this DiscordEmbedBuilder builder, DiscordClient client, DiscordMessage message, ISource source, LogParseState state = null)
+        internal static DiscordEmbedBuilder AddAuthor(this DiscordEmbedBuilder builder, DiscordClient client, DiscordMessage? message, ISource source, LogParseState? state = null)
         {
-            if (state?.Error == LogParseState.ErrorCode.PiracyDetected)
+            if (message == null || state?.Error == LogParseState.ErrorCode.PiracyDetected)
                 return builder;
 
-            if (message != null)
-            {
-                var author = message.Author;
-                var member = client.GetMember(message.Channel?.Guild, author);
-                string msg;
-                if (member == null)
-                    msg = $"Log from {author.Username.Sanitize()} | {author.Id}\n";
-                else
-                    msg = $"Log from {member.DisplayName.Sanitize()} | {member.Id}\n";
-                msg += " | " + (source?.SourceType ?? "Unknown source");
-                if (state?.ReadBytes > 0 && source?.LogFileSize > 0 && source.LogFileSize < 2L*1024*1024*1024 && state.ReadBytes <= source.LogFileSize)
-                    msg += $" | Parsed {state.ReadBytes * 100.0 / source.LogFileSize:0.##}%";
-                else if (source?.SourceFilePosition > 0 && source.SourceFileSize > 0 && source.SourceFilePosition <= source.SourceFileSize)
-                    msg += $" | Read {source.SourceFilePosition * 100.0 / source.SourceFileSize:0.##}%";
-                else if (state?.ReadBytes > 0)
-                    msg += $" | Parsed {state.ReadBytes} byte{(state.ReadBytes == 1 ? "" : "s")}";
-                else if (source?.LogFileSize > 0)
-                    msg += $" | {source.LogFileSize} byte{(source.LogFileSize == 1 ? "" : "s")}";
+            var author = message.Author;
+            var member = client.GetMember(message.Channel?.Guild, author);
+            string msg;
+            if (member == null)
+                msg = $"Log from {author.Username.Sanitize()} | {author.Id}\n";
+            else
+                msg = $"Log from {member.DisplayName.Sanitize()} | {member.Id}\n";
+            msg += " | " + (source?.SourceType ?? "Unknown source");
+            if (state?.ReadBytes > 0 && source?.LogFileSize > 0 && source.LogFileSize < 2L*1024*1024*1024 && state.ReadBytes <= source.LogFileSize)
+                msg += $" | Parsed {state.ReadBytes * 100.0 / source.LogFileSize:0.##}%";
+            else if (source?.SourceFilePosition > 0 && source.SourceFileSize > 0 && source.SourceFilePosition <= source.SourceFileSize)
+                msg += $" | Read {source.SourceFilePosition * 100.0 / source.SourceFileSize:0.##}%";
+            else if (state?.ReadBytes > 0)
+                msg += $" | Parsed {state.ReadBytes} byte{(state.ReadBytes == 1 ? "" : "s")}";
+            else if (source?.LogFileSize > 0)
+                msg += $" | {source.LogFileSize} byte{(source.LogFileSize == 1 ? "" : "s")}";
 #if DEBUG
-                if (state?.ParsingTime.TotalMilliseconds > 0)
-                    msg += $" | {state.ParsingTime.TotalSeconds:0.###}s";
-                msg += " | Test Bot Instance";
+            if (state?.ParsingTime.TotalMilliseconds > 0)
+                msg += $" | {state.ParsingTime.TotalSeconds:0.###}s";
+            msg += " | Test Bot Instance";
 #endif
-                builder.WithFooter(msg);
-            }
+            builder.WithFooter(msg);
             return builder;
         }
 
@@ -864,8 +866,8 @@ namespace CompatBot.Utils.ResultFormatters
 
             foreach (var error in fatalErrors[1..])
             {
-                int idx = -1;
-                double similarity = 0.0;
+                var idx = -1;
+                var similarity = 0.0;
                 for (var i = 0; i < result.Count; i++)
                 {
                     similarity = result[i].fatalError.GetFuzzyCoefficientCached(error);

CompatBot/Utils/ResultFormatters/PrInfoFormatter.cs

@@ -21,7 +21,7 @@ namespace CompatBot.Utils.ResultFormatters
             return new DiscordEmbedBuilder {Title = title, Url = issueInfo.HtmlUrl, Description = issueInfo.Title, Color = state.color};
         }
 
-        public static (string state, DiscordColor color) GetState(this PrInfo prInfo)
+        public static (string? state, DiscordColor color) GetState(this PrInfo prInfo)
         {
             if (prInfo.State == "open")
                 return ("Open", Config.Colors.PrOpen);
@@ -37,7 +37,7 @@ namespace CompatBot.Utils.ResultFormatters
             return (null, Config.Colors.DownloadLinks);
         }
 
-        public static (string state, DiscordColor color) GetState(this IssueInfo issueInfo)
+        public static (string? state, DiscordColor color) GetState(this IssueInfo issueInfo)
         {
             if (issueInfo.State == "open")
                 return ("Open", Config.Colors.PrOpen);

CompatBot/Utils/ResultFormatters/TitleInfoFormatter.cs

@@ -24,10 +24,12 @@ namespace CompatBot.Utils.ResultFormatters
 			{"Playable", Config.Colors.CompatStatusPlayable},
 		};
 
-        public static string ToUpdated(this TitleInfo info)
-            => DateTime.TryParseExact(info.Date, ApiConfig.DateInputFormat, DateTimeFormatInfo.InvariantInfo, DateTimeStyles.AssumeUniversal, out var date) ? date.ToString(ApiConfig.DateOutputFormat) : null;
+        public static string? ToUpdated(this TitleInfo info)
+            => DateTime.TryParseExact(info.Date, ApiConfig.DateInputFormat, DateTimeFormatInfo.InvariantInfo, DateTimeStyles.AssumeUniversal, out var date)
+                ? date.ToString(ApiConfig.DateOutputFormat)
+                : null;
 
-        private static string ToPrString(this TitleInfo info, string defaultString, bool link = false)
+        private static string? ToPrString(this TitleInfo info, string? defaultString, bool link = false)
         {
             if ((info.Pr ?? 0) == 0)
                 return defaultString;
@@ -63,7 +65,7 @@ namespace CompatBot.Utils.ResultFormatters
             return $"Product code {titleId} was not found in compatibility database";
         }
 
-        public static DiscordEmbedBuilder AsEmbed(this TitleInfo info, string titleId, string gameTitle = null, bool forLog = false, string thumbnailUrl = null)
+        public static DiscordEmbedBuilder AsEmbed(this TitleInfo info, string? titleId, string? gameTitle = null, bool forLog = false, string? thumbnailUrl = null)
         {
             if (string.IsNullOrWhiteSpace(gameTitle))
                 gameTitle = null;
@@ -82,10 +84,9 @@ namespace CompatBot.Utils.ResultFormatters
                         Title = thumb.Name,
                         UsingLocalCache = true,
                     };
-                    
                 }
             }
-            if (StatusColors.TryGetValue(info.Status, out var color))
+            if (info.Status is string status && StatusColors.TryGetValue(status, out var color))
             {
                 // apparently there's no formatting in the footer, but you need to escape everything in description; ugh
                 var onlineOnlypart = info.Network == 1 ? " 🌐" : "";
@@ -105,7 +106,7 @@ namespace CompatBot.Utils.ResultFormatters
                     StatsStorage.GameStatCache.TryGetValue(cacheTitle, out int stat);
                     StatsStorage.GameStatCache.Set(cacheTitle, ++stat, StatsStorage.CacheTime);
                 }
-                var title = $"{productCodePart}{cacheTitle.Trim(200)}{onlineOnlypart}";
+                var title = $"{productCodePart}{cacheTitle?.Trim(200)}{onlineOnlypart}";
                 if (string.IsNullOrEmpty(title))
                     desc = "";
                 return new DiscordEmbedBuilder
@@ -151,18 +152,12 @@ namespace CompatBot.Utils.ResultFormatters
         }
 
         public static string AsString(this (string code, TitleInfo info, double score) resultInfo)
-        {
-            return resultInfo.info.AsString(resultInfo.code);
-        }
+            => resultInfo.info.AsString(resultInfo.code);
 
         public static string AsString(this KeyValuePair<string, TitleInfo> resultInfo)
-        {
-            return resultInfo.Value.AsString(resultInfo.Key);
-        }
+            => resultInfo.Value.AsString(resultInfo.Key);
 
         public static DiscordEmbed AsEmbed(this KeyValuePair<string, TitleInfo> resultInfo)
-        {
-            return resultInfo.Value.AsEmbed(resultInfo.Key);
-        }
+            => resultInfo.Value.AsEmbed(resultInfo.Key);
     }
 }

CompatBot/Utils/ResultFormatters/UpdateInfoFormatter.cs

@@ -18,17 +18,17 @@ namespace CompatBot.Utils.ResultFormatters
     {
         private static readonly GithubClient.Client githubClient = new GithubClient.Client();
 
-        public static async Task<DiscordEmbedBuilder> AsEmbedAsync(this UpdateInfo info, DiscordClient client, bool includePrBody = false, DiscordEmbedBuilder builder = null, PrInfo currentPrInfo = null)
+        public static async Task<DiscordEmbedBuilder> AsEmbedAsync(this UpdateInfo? info, DiscordClient client, bool includePrBody = false, DiscordEmbedBuilder? builder = null, PrInfo? currentPrInfo = null)
         {
-            if ((info?.LatestBuild?.Windows?.Download ?? info?.LatestBuild?.Linux?.Download) == null)
+            if ((info?.LatestBuild?.Windows?.Download ?? info?.LatestBuild?.Linux?.Download) is null)
                 return builder ?? new DiscordEmbedBuilder {Title = "Error", Description = "Error communicating with the update API. Try again later.", Color = Config.Colors.Maintenance};
 
             var justAppend = builder != null;
-            var latestBuild = info.LatestBuild;
+            var latestBuild = info!.LatestBuild;
             var latestPr = latestBuild?.Pr;
             var currentPr = info.CurrentBuild?.Pr;
-            string url = null;
-            PrInfo latestPrInfo = null;
+            string? url = null;
+            PrInfo? latestPrInfo = null;
 
             string prDesc = "";
             if (!justAppend)
@@ -38,8 +38,7 @@ namespace CompatBot.Utils.ResultFormatters
                     latestPrInfo = await githubClient.GetPrInfoAsync(latestPr.Value, Config.Cts.Token).ConfigureAwait(false);
                     url = latestPrInfo?.HtmlUrl ?? "https://github.com/RPCS3/rpcs3/pull/" + latestPr;
                     var userName = latestPrInfo?.User?.Login ?? "???";
-                    var emoji = GetUserNameEmoji(client, userName);
-                    if (emoji != null)
+                    if (GetUserNameEmoji(client, userName) is DiscordEmoji emoji)
                         userName += " " + emoji;
                     prDesc = $"PR #{latestPr} by {userName}";
                 }
@@ -53,7 +52,7 @@ namespace CompatBot.Utils.ResultFormatters
             if (includePrBody
                 && latestPrInfo?.Body is string prInfoBody
                 && !string.IsNullOrEmpty(prInfoBody))
-                desc = $"**{desc.TrimEnd()}**\n\n{prInfoBody}";
+                desc = $"**{desc?.TrimEnd()}**\n\n{prInfoBody}";
             desc = desc?.Trim();
             if (!string.IsNullOrEmpty(desc))
             {
@@ -87,7 +86,7 @@ namespace CompatBot.Utils.ResultFormatters
                     var uniqueLinks = new HashSet<string>(2);
                     foreach (Match m in commitMatches)
                     {
-                        if (m.Groups["commit_mention"]?.Value is string lnk
+                        if (m.Groups["commit_mention"].Value is string lnk
                             && !string.IsNullOrEmpty(lnk)
                             && uniqueLinks.Add(lnk))
                         {
@@ -109,7 +108,7 @@ namespace CompatBot.Utils.ResultFormatters
                 var uniqueLinks = new HashSet<string>(10);
                 foreach (Match m in imgMatches)
                 {
-                    if (m.Groups["img_markup"]?.Value is string str
+                    if (m.Groups["img_markup"].Value is string str
                         && !string.IsNullOrEmpty(str)
                         && uniqueLinks.Add(str))
                     {
@@ -121,20 +120,23 @@ namespace CompatBot.Utils.ResultFormatters
                     }
                 }
             }
-            desc = desc.Trim(EmbedPager.MaxDescriptionLength);
+            desc = desc?.Trim(EmbedPager.MaxDescriptionLength);
             builder ??= new DiscordEmbedBuilder {Title = prDesc, Url = url, Description = desc, Color = Config.Colors.DownloadLinks};
             var currentCommit = currentPrInfo?.MergeCommitSha;
             var latestCommit = latestPrInfo?.MergeCommitSha;
             var buildTimestampKind = "Built";
-            var azureClient = Config.GetAzureDevOpsClient();
-            var currentAppveyorBuild = await azureClient.GetMasterBuildInfoAsync(currentCommit, currentPrInfo?.MergedAt, Config.Cts.Token).ConfigureAwait(false);
-            var latestAppveyorBuild = await azureClient.GetMasterBuildInfoAsync(latestCommit, latestPrInfo?.MergedAt, Config.Cts.Token).ConfigureAwait(false);
-            var latestBuildTimestamp = latestAppveyorBuild?.FinishTime;
-            var currentBuildTimestamp = currentAppveyorBuild?.FinishTime;
-            if (!latestBuildTimestamp.HasValue)
+            DateTime? latestBuildTimestamp = null, currentBuildTimestamp = null;
+            if (Config.GetAzureDevOpsClient() is {} azureClient)
             {
-                buildTimestampKind = "Merged";
-                latestBuildTimestamp = currentPrInfo?.MergedAt;
+                var currentAppveyorBuild = await azureClient.GetMasterBuildInfoAsync(currentCommit, currentPrInfo?.MergedAt, Config.Cts.Token).ConfigureAwait(false);
+                var latestAppveyorBuild = await azureClient.GetMasterBuildInfoAsync(latestCommit, latestPrInfo?.MergedAt, Config.Cts.Token).ConfigureAwait(false);
+                latestBuildTimestamp = latestAppveyorBuild?.FinishTime;
+                currentBuildTimestamp = currentAppveyorBuild?.FinishTime;
+                if (!latestBuildTimestamp.HasValue)
+                {
+                    buildTimestampKind = "Merged";
+                    latestBuildTimestamp = currentPrInfo?.MergedAt;
+                }
             }
 
             if (!string.IsNullOrEmpty(latestBuild?.Datetime))
@@ -158,7 +160,7 @@ namespace CompatBot.Utils.ResultFormatters
                 .AddField("Linux download", GetLinkMessage(latestBuild?.Linux?.Download, true), true);
         }
 
-        private static string GetLinkMessage(string link, bool simpleName)
+        private static string GetLinkMessage(string? link, bool simpleName)
         {
             if (string.IsNullOrEmpty(link))
                 return "No link available";
@@ -172,7 +174,7 @@ namespace CompatBot.Utils.ResultFormatters
             return $"[⏬ {text}]({link}){"   ".FixSpaces()}";
         }
 
-        private static DiscordEmoji GetUserNameEmoji(DiscordClient client, string githubLogin)
+        private static DiscordEmoji? GetUserNameEmoji(DiscordClient client, string githubLogin)
             => client.GetEmoji(githubLogin switch
             {
 #if DEBUG
@@ -206,7 +208,7 @@ namespace CompatBot.Utils.ResultFormatters
             return null;
         }
 
-        public static TimeSpan? GetUpdateDelta(this UpdateInfo updateInfo)
+        public static TimeSpan? GetUpdateDelta(this UpdateInfo? updateInfo)
         {
             if (updateInfo?.LatestBuild?.Datetime is string latestDateTimeStr
                 && DateTime.TryParse(latestDateTimeStr, out var latestDateTime)

CompatBot/Utils/UniqueList.cs

@@ -10,23 +10,23 @@ namespace CompatBot.Utils
 		private readonly List<T> list;
 		private readonly HashSet<T> set;
 
-		public UniqueList(IEqualityComparer<T> comparer = null)
+		public UniqueList(IEqualityComparer<T>? comparer = null)
 		{
 			list = new List<T>();
 			set = new HashSet<T>(comparer);
-			this.Comparer = comparer;
+			Comparer = comparer;
 		}
 
-		public UniqueList(int count, IEqualityComparer<T> comparer = null)
+		public UniqueList(int count, IEqualityComparer<T>? comparer = null)
 		{
 			list = new List<T>(count);
 			set = new HashSet<T>(count, comparer);
-			this.Comparer = comparer;
+			Comparer = comparer;
 		}
 
-		public UniqueList(IEnumerable<T> collection, IEqualityComparer<T> comparer = null)
+		public UniqueList(IEnumerable<T> collection, IEqualityComparer<T>? comparer = null)
 		{
-			this.Comparer = comparer;
+			Comparer = comparer;
 			if (collection is ICollection c)
 			{
 				list = new List<T>(c.Count);
@@ -110,7 +110,7 @@ namespace CompatBot.Utils
 		}
 
 		public int Length => list.Count;
-		public IEqualityComparer<T> Comparer { get; }
+		public IEqualityComparer<T>? Comparer { get; }
 
 		T GetAt(int index) => list[index];
 	}

CompatBot/Watchdog.cs

@@ -19,7 +19,7 @@ namespace CompatBot
         public static readonly ConcurrentQueue<DateTime> DisconnectTimestamps = new ConcurrentQueue<DateTime>();
         public static readonly Stopwatch TimeSinceLastIncomingMessage = Stopwatch.StartNew();
         private static bool IsOk => DisconnectTimestamps.IsEmpty && TimeSinceLastIncomingMessage.Elapsed < Config.IncomingMessageCheckIntervalInMin;
-        private static DiscordClient discordClient = null;
+        private static DiscordClient? discordClient = null;
 
         public static async Task Watch(DiscordClient client)
         {
@@ -71,20 +71,21 @@ namespace CompatBot
         {
             if (level == nameof(LogLevel.Info))
             {
-                if (message?.Contains("Session resumed") ?? false)
+                if (message.Contains("Session resumed"))
                     DisconnectTimestamps.Clear();
             }
             else if (level == nameof(LogLevel.Warn))
             {
-                if (message?.Contains("Dispatch:PRESENCES_REPLACE") ?? false)
+                if (message.Contains("Dispatch:PRESENCES_REPLACE")
+                    && discordClient != null)
                     BotStatusMonitor.RefreshAsync(discordClient).ConfigureAwait(false).GetAwaiter().GetResult();
-                else if (message?.Contains("Pre-emptive ratelimit triggered") ?? false)
+                else if (message.Contains("Pre-emptive ratelimit triggered"))
                     Config.TelemetryClient?.TrackEvent("preemptive-rate-limit");
             }
             else if (level == nameof(LogLevel.Fatal))
             {
-                if ((message?.Contains("Socket connection terminated") ?? false)
-                    || (message?.Contains("heartbeats were skipped. Issuing reconnect.") ?? false))
+                if ((message.Contains("Socket connection terminated"))
+                    || (message.Contains("heartbeats were skipped. Issuing reconnect.")))
                     DisconnectTimestamps.Enqueue(DateTime.UtcNow);
             }
         }
@@ -94,12 +95,15 @@ namespace CompatBot
             do
             {
                 await Task.Delay(Config.MetricsIntervalInSec).ConfigureAwait(false);
+                var gcMemInfo = GC.GetGCMemoryInfo();
                 using var process = Process.GetCurrentProcess();
                 if (Config.TelemetryClient is TelemetryClient tc)
                 {
                     tc.TrackMetric("gw-latency", client.Ping);
                     tc.TrackMetric("time-since-last-incoming-message", TimeSinceLastIncomingMessage.ElapsedMilliseconds);
-                    tc.TrackMetric("memory-gc-total", GC.GetTotalMemory(false));
+                    tc.TrackMetric("memory-gc-total", gcMemInfo.HeapSizeBytes);
+                    tc.TrackMetric("memory-gc-load", gcMemInfo.MemoryLoadBytes);
+                    tc.TrackMetric("memory-gc-commited", gcMemInfo.TotalCommittedBytes);
                     tc.TrackMetric("memory-process-private", process.PrivateMemorySize64);
                     tc.TrackMetric("memory-process-ws", process.WorkingSet64);
                     tc.TrackMetric("github-limit-remaining", GithubClient.Client.RateLimitRemaining);
@@ -112,22 +116,16 @@ namespace CompatBot
         {
             do
             {
+                var gcMemInfo = GC.GetGCMemoryInfo();
                 using var process = Process.GetCurrentProcess();
                 Config.Log.Info($"Process memory stats:\n" +
-                                $"GC: {GC.GetTotalMemory(false)}\n" +
+                                $"GC Heap: {gcMemInfo.HeapSizeBytes}\n" +
                                 $"Private: {process.PrivateMemorySize64}\n" +
                                 $"Working set: {process.WorkingSet64}\n" +
                                 $"Virtual: {process.VirtualMemorySize64}\n" +
                                 $"Paged: {process.PagedMemorySize64}\n" +
                                 $"Paged sytem: {process.PagedSystemMemorySize64}\n" +
                                 $"Non-pated system: {process.NonpagedSystemMemorySize64}");
-                var processMemory = process.PrivateMemorySize64;
-                var gcMemory = GC.GetTotalMemory(false);
-                if (processMemory / (double)gcMemory > 2)
-                {
-                    GCSettings.LargeObjectHeapCompactionMode = GCLargeObjectHeapCompactionMode.CompactOnce;
-                    GC.Collect(2, GCCollectionMode.Optimized, true, true); // force LOH compaction
-                }
                 await Task.Delay(TimeSpan.FromHours(1)).ConfigureAwait(false);
             } while (!Config.Cts.IsCancellationRequested);
         }