From 12054cc89902c47bcef9759c2bb5c6401af9bf42 Mon Sep 17 00:00:00 2001
From: "Sergey \"Shnatsel\" Davidoff" <sdavydov@google.com>
Date: Wed, 29 Jul 2020 15:40:12 +0200
Subject: [PATCH] Fuzz: drop workarounds for operations that may panic (#92)

Fuzz: drop workarounds for operations that may panic now that rutenspitz compares panic behavior
---
 fuzz/Cargo.toml          |  2 +-
 fuzz/src/bin/arrayish.rs | 34 +++++++---------------------------
 fuzz/src/bin/tinyvec.rs  | 30 +++---------------------------
 3 files changed, 11 insertions(+), 55 deletions(-)

diff --git a/fuzz/Cargo.toml b/fuzz/Cargo.toml
index 346528a..b38aab3 100644
--- a/fuzz/Cargo.toml
+++ b/fuzz/Cargo.toml
@@ -7,7 +7,7 @@ publish = false
 
 [dependencies]
 tinyvec = { path = "..", features = ["alloc", "nightly_slice_partition_dedup"] }
-rutenspitz = "0.2"
+rutenspitz = "0.2.1"
 honggfuzz = "0.5.45"
 arbitrary = { version = "0.4.5", features = ["derive"] }
 better-panic = "0.2.0"
diff --git a/fuzz/src/bin/arrayish.rs b/fuzz/src/bin/arrayish.rs
index e04283e..0fa6791 100644
--- a/fuzz/src/bin/arrayish.rs
+++ b/fuzz/src/bin/arrayish.rs
@@ -2,7 +2,7 @@ use honggfuzz::fuzz;
 use std::{
   fmt::Debug,
   iter::FromIterator,
-  ops::{Bound, RangeBounds},
+  ops::RangeBounds,
 };
 use rutenspitz::arbitrary_stateful_operations;
 
@@ -47,37 +47,16 @@ arbitrary_stateful_operations! {
 
     pre {
         match self {
-            Self::insert { index, .. } | Self::split_off { at: index } if index > model.len() => {
-                // TODO: Should test that these identically panic
-                return;
-            }
-            Self::remove { index } | Self::swap_remove { index } if index >= model.len() => {
-                // TODO: Should test that these identically panic
-                return;
-            }
+            // We are comparing ArrayVec with a limited capacity against
+            // Vec to which you can push indefinitely. This is a behavior mismatch.
+            // To compensate we skip adding any elements if it would exceed capacity.
             Self::insert { .. } | Self::push { .. } if model.len() == CAPACITY => {
                 return;
             }
             Self::resize { new_len, .. } if new_len > CAPACITY => {
                 return;
             }
-            Self::drain { ref range } => {
-                // TODO: Should test that these identically panic
-                let start = match range.start_bound() {
-                    Bound::Included(&n) => n,
-                    Bound::Excluded(&n) => n + 1,
-                    Bound::Unbounded => 0,
-                };
-                let end = match range.end_bound() {
-                    // If it's already usize::max, doesn't really matter about adding 1
-                    Bound::Included(&n) => n.checked_add(1).unwrap_or(n),
-                    Bound::Excluded(&n) => n,
-                    Bound::Unbounded => model.len(),
-                };
-                if start > end || end > model.len() {
-                    return;
-                }
-            }
+
             _ => {}
         }
     }
@@ -89,7 +68,7 @@ fn fuzz_cycle(data: &[u8]) -> Result<(), ()> {
   let mut ring = Unstructured::new(&data);
 
   let mut model = Vec::<u16>::default();
-  let mut tested: ArrayVec<[u16; 32]> = ArrayVec::new();
+  let mut tested: ArrayVec<[u16; CAPACITY]> = ArrayVec::new();
 
   let mut _op_trace = String::new();
   while let Ok(op) =
@@ -97,6 +76,7 @@ fn fuzz_cycle(data: &[u8]) -> Result<(), ()> {
   {
     #[cfg(fuzzing_debug)]
     _op_trace.push_str(&format!("{}\n", op.to_string()));
+    // println!("Operations trace:\n{}", _op_trace);
     op.execute_and_compare(&mut model, &mut tested);
   }
 
diff --git a/fuzz/src/bin/tinyvec.rs b/fuzz/src/bin/tinyvec.rs
index c89fd8d..87040ea 100644
--- a/fuzz/src/bin/tinyvec.rs
+++ b/fuzz/src/bin/tinyvec.rs
@@ -2,7 +2,7 @@ use honggfuzz::fuzz;
 use std::{
   fmt::Debug,
   iter::FromIterator,
-  ops::{Bound, RangeBounds},
+  ops::RangeBounds,
 };
 use rutenspitz::arbitrary_stateful_operations;
 
@@ -47,35 +47,10 @@ arbitrary_stateful_operations! {
 
     pre {
         match self {
-            Self::insert { index, .. } | Self::split_off { at: index } if index > model.len() => {
-                // TODO: Should test that these identically panic
-                return;
-            }
-            Self::remove { index } | Self::swap_remove { index } if index >= model.len() => {
-                // TODO: Should test that these identically panic
-                return;
-            }
             // Arbitrary limit to avoid allocating too large a buffer
             Self::resize { new_len, .. } if new_len > 4 * CAPACITY => {
                 return;
             }
-            Self::drain { ref range } => {
-                // TODO: Should test that these identically panic
-                let start = match range.start_bound() {
-                    Bound::Included(&n) => n,
-                    Bound::Excluded(&n) => n + 1,
-                    Bound::Unbounded => 0,
-                };
-                let end = match range.end_bound() {
-                    // If it's already usize::max, doesn't really matter about adding 1
-                    Bound::Included(&n) => n.checked_add(1).unwrap_or(n),
-                    Bound::Excluded(&n) => n,
-                    Bound::Unbounded => model.len(),
-                };
-                if start > end || end > model.len() {
-                    return;
-                }
-            }
             _ => {}
         }
     }
@@ -87,7 +62,7 @@ fn fuzz_cycle(data: &[u8]) -> Result<(), ()> {
   let mut ring = Unstructured::new(&data);
 
   let mut model = Vec::<u16>::default();
-  let mut tested: TinyVec<[u16; 32]> = TinyVec::new();
+  let mut tested: TinyVec<[u16; CAPACITY]> = TinyVec::new();
 
   let mut _op_trace = String::new();
   while let Ok(op) =
@@ -95,6 +70,7 @@ fn fuzz_cycle(data: &[u8]) -> Result<(), ()> {
   {
     #[cfg(fuzzing_debug)]
     _op_trace.push_str(&format!("{}\n", op.to_string()));
+    // println!("Operations trace:\n{}", _op_trace);
     op.execute_and_compare(&mut model, &mut tested);
   }