fix(core): expose filesystem failures

packages/core/src/filesystem.ts

@@ -7,8 +7,8 @@ import { FSUtil } from "./fs-util"
 import { Location } from "./location"
 import { PositiveInt, RelativePath } from "./schema"
 import { FileSystemSearch } from "./filesystem/search"
-import { Entry, Match } from "./filesystem/schema"
-export { Entry, Match, Submatch } from "./filesystem/schema"
+import { Entry, Match, PathError } from "./filesystem/schema"
+export { Entry, Match, PathError, Submatch } from "./filesystem/schema"
 
 export const ReadInput = Schema.Struct({
   path: RelativePath,
@@ -58,8 +58,10 @@ export const Event = {
 }
 
 export interface Interface {
-  readonly read: (input: ReadInput) => Effect.Effect<{ readonly content: Uint8Array; readonly mime: string }>
-  readonly list: (input?: ListInput) => Effect.Effect<Entry[]>
+  readonly read: (
+    input: ReadInput,
+  ) => Effect.Effect<{ readonly content: Uint8Array; readonly mime: string }, PathError | FSUtil.Error>
+  readonly list: (input?: ListInput) => Effect.Effect<Entry[], PathError | FSUtil.Error>
   readonly find: (input: FindInput) => Effect.Effect<Entry[]>
   readonly glob: (input: GlobInput) => Effect.Effect<readonly Entry[]>
   readonly grep: (input: GrepInput) => Effect.Effect<readonly Match[]>
@@ -77,9 +79,9 @@ const baseLayer = Layer.effect(
     const resolve = Effect.fnUntraced(function* (input?: RelativePath) {
       const absolute = path.resolve(location.directory, input ?? ".")
       if (!FSUtil.contains(location.directory, absolute))
-        return yield* Effect.die(new Error("Path escapes the location"))
-      const real = yield* fs.realPath(absolute).pipe(Effect.orDie)
-      if (!FSUtil.contains(root, real)) return yield* Effect.die(new Error("Path escapes the location"))
+        return yield* new PathError({ path: input ?? ".", reason: "lexical_escape" })
+      const real = yield* fs.realPath(absolute)
+      if (!FSUtil.contains(root, real)) return yield* new PathError({ path: input ?? ".", reason: "symlink_escape" })
       return { absolute, real, directory: location.directory, root }
     })
     return Service.of({
@@ -88,19 +90,18 @@ const baseLayer = Layer.effect(
       grep: search.grep,
       read: Effect.fn("FileSystem.read")(function* (input) {
         const target = yield* resolve(input.path)
-        const info = yield* fs.stat(target.real).pipe(Effect.orDie)
-        if (info.type !== "File") return yield* Effect.die(new Error("Path is not a file"))
+        const info = yield* fs.stat(target.real)
+        if (info.type !== "File") return yield* new PathError({ path: input.path, reason: "not_file" })
         return {
-          content: yield* fs.readFile(target.real).pipe(Effect.orDie),
+          content: yield* fs.readFile(target.real),
           mime: FSUtil.mimeType(target.real),
         }
       }),
       list: Effect.fn("FileSystem.list")(function* (input = {}) {
         const target = yield* resolve(input.path)
-        const info = yield* fs.stat(target.real).pipe(Effect.orDie)
-        if (info.type !== "Directory") return yield* Effect.die(new Error("Path is not a directory"))
+        const info = yield* fs.stat(target.real)
+        if (info.type !== "Directory") return yield* new PathError({ path: input.path ?? ".", reason: "not_directory" })
         return yield* fs.readDirectoryEntries(target.real).pipe(
-          Effect.orDie,
           Effect.map((items) =>
             items
               .flatMap((item) => {

packages/core/src/filesystem/schema.ts

@@ -21,3 +21,8 @@ export class Match extends Schema.Class<Match>("FileSystem.Match")({
   text: Schema.String,
   submatches: Schema.Array(Submatch),
 }) {}
+
+export class PathError extends Schema.TaggedErrorClass<PathError>()("FileSystem.PathError", {
+  path: Schema.String,
+  reason: Schema.Literals(["lexical_escape", "symlink_escape", "not_file", "not_directory"]),
+}) {}

packages/core/test/location-filesystem.test.ts

@@ -1,7 +1,7 @@
 import fs from "fs/promises"
 import path from "path"
 import { describe, expect } from "bun:test"
-import { Effect, Exit, Layer } from "effect"
+import { Cause, Effect, Exit, Layer } from "effect"
 import { FileSystem } from "@opencode-ai/core/filesystem"
 import { FSUtil } from "@opencode-ai/core/fs-util"
 import { Location } from "@opencode-ai/core/location"
@@ -31,6 +31,13 @@ const withTmp = <A, E, R>(f: (directory: string) => Effect.Effect<A, E, R>) =>
   ).pipe(Effect.flatMap((tmp) => f(tmp.path)))
 
 describe("FileSystem", () => {
+  const expectFail = (exit: Exit.Exit<unknown, unknown>) => {
+    expect(Exit.isFailure(exit)).toBe(true)
+    if (Exit.isSuccess(exit)) return
+    expect(Cause.hasFails(exit.cause)).toBe(true)
+    expect(Cause.hasDies(exit.cause)).toBe(false)
+  }
+
   it.live("reads text and binary files", () =>
     withTmp((directory) =>
       Effect.gen(function* () {
@@ -60,13 +67,39 @@ describe("FileSystem", () => {
     ),
   )
 
-  it.live("rejects lexical escapes", () =>
+  it.live("fails for missing paths", () =>
     withTmp((directory) =>
       Effect.gen(function* () {
-        const result = yield* (yield* FileSystem.Service)
-          .read({ path: RelativePath.make("../outside.txt") })
+        const exit = yield* (yield* FileSystem.Service)
+          .read({ path: RelativePath.make("missing.txt") })
           .pipe(Effect.exit)
-        expect(Exit.isFailure(result)).toBe(true)
+        expectFail(exit)
+      }).pipe(provide(directory)),
+    ),
+  )
+
+  it.live("fails for wrong path kinds", () =>
+    withTmp((directory) =>
+      Effect.gen(function* () {
+        yield* Effect.promise(() => fs.mkdir(path.join(directory, "src")))
+        yield* Effect.promise(() => fs.writeFile(path.join(directory, "README.md"), "# Test"))
+        const service = yield* FileSystem.Service
+        expectFail(yield* service.read({ path: RelativePath.make("src") }).pipe(Effect.exit))
+        expectFail(yield* service.list({ path: RelativePath.make("README.md") }).pipe(Effect.exit))
+      }).pipe(provide(directory)),
+    ),
+  )
+
+  it.live("fails for lexical and symlink escapes", () =>
+    withTmp((directory) =>
+      Effect.gen(function* () {
+        const outside = path.join(directory, "..", "outside.txt")
+        yield* Effect.promise(() => fs.writeFile(outside, "outside"))
+        yield* Effect.promise(() => fs.symlink(outside, path.join(directory, "linked.txt")))
+        const service = yield* FileSystem.Service
+        expectFail(yield* service.read({ path: RelativePath.make("../outside.txt") }).pipe(Effect.exit))
+        expectFail(yield* service.read({ path: RelativePath.make("linked.txt") }).pipe(Effect.exit))
+        yield* Effect.promise(() => fs.rm(outside))
       }).pipe(provide(directory)),
     ),
   )

packages/plugin/src/v2/effect/filesystem.ts

@@ -1,9 +1,25 @@
 import type { FileSystemEntry } from "@opencode-ai/sdk/v2/types"
 import type { Effect } from "effect"
+import type { PlatformError } from "effect/PlatformError"
+
+export type FileSystemError =
+  | PlatformError
+  | {
+      readonly _tag: "FileSystemError"
+      readonly method: string
+      readonly cause?: unknown
+    }
+  | {
+      readonly _tag: "FileSystem.PathError"
+      readonly path: string
+      readonly reason: "lexical_escape" | "symlink_escape" | "not_file" | "not_directory"
+    }
 
 export interface FileSystem {
-  read(input: { readonly path: string }): Effect.Effect<{ readonly content: Uint8Array; readonly mime: string }>
-  list(input?: { readonly path?: string }): Effect.Effect<FileSystemEntry[]>
+  read(input: {
+    readonly path: string
+  }): Effect.Effect<{ readonly content: Uint8Array; readonly mime: string }, FileSystemError>
+  list(input?: { readonly path?: string }): Effect.Effect<FileSystemEntry[], FileSystemError>
   find(input: {
     readonly query: string
     readonly type?: "file" | "directory"

packages/plugin/src/v2/effect/index.ts

@@ -7,7 +7,7 @@ export type { AISDK, AISDKHooks } from "./aisdk.js"
 export type { Catalog, CatalogDraft, CatalogProviderRecord } from "./catalog.js"
 export type { Command, CommandDraft } from "./command.js"
 export type { Event, EventMap } from "./event.js"
-export type { FileSystem } from "./filesystem.js"
+export type { FileSystem, FileSystemError } from "./filesystem.js"
 export type { Integration, IntegrationDraft, IntegrationMethod, IntegrationMethodRegistration } from "./integration.js"
 export type { Location } from "./location.js"
 export type { Npm } from "./npm.js"