test(core): simplify file mutation layer wiring

packages/core/src/file-mutation.ts

@@ -3,6 +3,7 @@ export * as FileMutation from "./file-mutation"
 import { Context, Effect, Layer, Schema } from "effect"
 import { dirname } from "path"
 import { KeyedMutex } from "./effect/keyed-mutex"
+import { LayerNode } from "./effect/layer-node"
 import { FSUtil } from "./fs-util"
 
 export interface Target {
@@ -171,6 +172,8 @@ export const layer = Layer.effect(
   }),
 )
 
+export const node = LayerNode.make(layer, [FSUtil.node])
+
 function splitBom(text: string) {
   const stripped = text.replace(/^\uFEFF+/, "")
   return { bom: stripped.length !== text.length, text: stripped }

packages/core/src/location-mutation.ts

@@ -2,6 +2,7 @@ export * as LocationMutation from "./location-mutation"
 
 import path from "path"
 import { Context, Effect, Layer, Schema } from "effect"
+import { LayerNode } from "./effect/layer-node"
 import { FSUtil } from "./fs-util"
 import { Location } from "./location"
 
@@ -153,3 +154,5 @@ export const layer = Layer.effect(
 )
 
 export const locationLayer = layer
+
+export const node = (location: LayerNode.Node<Location.Service>) => LayerNode.make(layer, [FSUtil.node, location])

packages/core/test/file-mutation.test.ts

@@ -2,6 +2,7 @@ import fs from "fs/promises"
 import path from "path"
 import { describe, expect } from "bun:test"
 import { Deferred, Effect, Fiber, Layer } from "effect"
+import { LayerNode } from "@opencode-ai/core/effect/layer-node"
 import { FileMutation } from "@opencode-ai/core/file-mutation"
 import { FSUtil } from "@opencode-ai/core/fs-util"
 import { Location } from "@opencode-ai/core/location"
@@ -11,14 +12,16 @@ import { location } from "./fixture/location"
 import { tmpdir } from "./fixture/tmpdir"
 import { it } from "./lib/effect"
 
-function provide(directory: string, filesystem = FSUtil.defaultLayer) {
-  const activeLocation = Layer.succeed(
-    Location.Service,
-    Location.Service.of(location({ directory: AbsolutePath.make(directory) })),
+function provide(directory: string, filesystem?: LayerNode.Replacement<FSUtil.Service>) {
+  const activeLocation = LayerNode.make(
+    Layer.succeed(Location.Service, Location.Service.of(location({ directory: AbsolutePath.make(directory) }))),
+    [],
+  )
+  return Effect.provide(
+    LayerNode.buildLayer(LayerNode.group([LocationMutation.node(activeLocation), FileMutation.node]), {
+      replacements: filesystem ? [filesystem] : [],
+    }),
   )
-  const resolution = LocationMutation.layer.pipe(Layer.provide(filesystem), Layer.provide(activeLocation))
-  const mutation = FileMutation.layer.pipe(Layer.provide(filesystem))
-  return Effect.provide(Layer.mergeAll(resolution, mutation))
 }
 
 function withTmp<A, E, R>(f: (directory: string) => Effect.Effect<A, E, R>) {
@@ -347,17 +350,20 @@ describe("FileMutation", () => {
 })
 
 function instrumentWrites(run: <E>(write: Effect.Effect<void, E>, target: string) => Effect.Effect<void, E>) {
-  return Layer.effect(
-    FSUtil.Service,
-    Effect.gen(function* () {
-      const filesystem = yield* FSUtil.Service
-      return FSUtil.Service.of({
-        ...filesystem,
-        writeWithDirs: (target, content, mode) => run(filesystem.writeWithDirs(target, content, mode), target),
-        writeFile: (target, content, options) => run(filesystem.writeFile(target, content, options), target),
-        writeFileString: (target, content, options) =>
-          run(filesystem.writeFileString(target, content, options), target),
-      })
-    }),
-  ).pipe(Layer.provide(FSUtil.defaultLayer))
+  return LayerNode.replace(
+    FSUtil.node,
+    Layer.effect(
+      FSUtil.Service,
+      Effect.gen(function* () {
+        const filesystem = yield* FSUtil.Service
+        return FSUtil.Service.of({
+          ...filesystem,
+          writeWithDirs: (target, content, mode) => run(filesystem.writeWithDirs(target, content, mode), target),
+          writeFile: (target, content, options) => run(filesystem.writeFile(target, content, options), target),
+          writeFileString: (target, content, options) =>
+            run(filesystem.writeFileString(target, content, options), target),
+        })
+      }),
+    ).pipe(Layer.provide(LayerNode.buildLayer(FSUtil.node))),
+  )
 }

packages/core/test/filesystem/watcher.test.ts

@@ -4,7 +4,6 @@ import fs from "fs/promises"
 import path from "path"
 import { ConfigProvider, Deferred, Duration, Effect, Fiber, Layer, Option, Stream } from "effect"
 import { Config } from "@opencode-ai/core/config"
-import { LayerNode } from "@opencode-ai/core/effect/layer-node"
 import { EventV2 } from "@opencode-ai/core/event"
 import { FSUtil } from "@opencode-ai/core/fs-util"
 import { Watcher } from "@opencode-ai/core/filesystem/watcher"
@@ -19,8 +18,7 @@ const describeWatcher = Watcher.hasNativeBinding() && !process.env.CI ? describe
 
 type WatcherEvent = { file: string; event: "add" | "change" | "unlink" }
 
-const root = LayerNode.group([FSUtil.node, EventV2.node])
-const it = testEffect(LayerNode.buildLayer(root))
+const it = testEffect(Layer.mergeAll(FSUtil.defaultLayer, EventV2.defaultLayer))
 
 const configLayer = Layer.succeed(
   Config.Service,
@@ -28,7 +26,6 @@ const configLayer = Layer.succeed(
     entries: () => Effect.succeed([]),
   }),
 )
-const configNode = LayerNode.make(configLayer, [])
 
 const flagsLayer = ConfigProvider.layer(
   ConfigProvider.fromUnknown({
@@ -38,21 +35,15 @@ const flagsLayer = ConfigProvider.layer(
 )
 
 function provide(directory: string, vcs?: Location.Interface["vcs"]) {
-  const locationNode = LayerNode.make(
-    Layer.succeed(
-      Location.Service,
-      Location.Service.of(location({ directory: AbsolutePath.make(directory) }, { vcs })),
-    ),
-    [],
+  const locationLayer = Layer.succeed(
+    Location.Service,
+    Location.Service.of(location({ directory: AbsolutePath.make(directory) }, { vcs })),
   )
   return Effect.provide(
-    LayerNode.buildLayer(
-      LayerNode.group([
-        LayerNode.make(Watcher.layer, [configNode, EventV2.node, FSUtil.node, Git.node, locationNode]),
-        root,
-      ]),
-      { replacements: [LayerNode.replace(configNode, configLayer)] },
-    ).pipe(
+    Watcher.layer.pipe(
+      Layer.provide(configLayer),
+      Layer.provide(Git.defaultLayer),
+      Layer.provide(locationLayer),
       Layer.provide(flagsLayer),
     ),
   )
@@ -205,7 +196,7 @@ describeWatcher("Watcher", () => {
       yield* noUpdate((event) => event.file === file, fs.writeFileString(file, "gone")).pipe(
         Effect.provideService(EventV2.Service, events),
       )
-    }).pipe(Effect.provide(LayerNode.buildLayer(root))),
+    }).pipe(Effect.provide(Layer.mergeAll(FSUtil.defaultLayer, EventV2.defaultLayer))),
   )
 
   it.live("ignores .git/index changes", () =>