fix(opencode): handle shell capture failures

packages/core/src/cross-spawn-spawner.ts

@@ -268,17 +268,16 @@ export const make = Effect.gen(function* () {
     Effect.callback<readonly [NodeChildProcess.ChildProcess, ExitSignal], PlatformError.PlatformError>((resume) => {
       const signal = Deferred.makeUnsafe<readonly [code: number | null, signal: NodeJS.Signals | null]>()
       const proc = launch(command.command, command.args, opts)
-      let end = false
       let exit: readonly [code: number | null, signal: NodeJS.Signals | null] | undefined
       proc.on("error", (err) => {
         resume(Effect.fail(toPlatformError("spawn", err, command)))
       })
       proc.on("exit", (...args) => {
         exit = args
+        Deferred.doneUnsafe(signal, Exit.succeed(args))
       })
       proc.on("close", (...args) => {
-        if (end) return
+        // cross-spawn can suppress `exit` for a Windows ENOENT and only emit `close`.
-        end = true
         Deferred.doneUnsafe(signal, Exit.succeed(exit ?? args))
       })
       proc.on("spawn", () => {

packages/core/test/effect/cross-spawn-spawner.test.ts

@@ -285,6 +285,46 @@ describe("cross-spawn spawner", () => {
         expect(running).toBe(false)
       }),
     )
+
+    fx.effect(
+      "resolves exit before inherited output pipes close",
+      Effect.gen(function* () {
+        const tmp = yield* Effect.acquireRelease(
+          Effect.promise(() => tmpdir()),
+          (tmp) => Effect.promise(() => tmp[Symbol.asyncDispose]()),
+        )
+        const file = path.join(tmp.path, "child.pid")
+        const child = "setInterval(() => {}, 10_000)"
+        const handle = yield* ChildProcess.make(process.execPath, [
+          "-e",
+          [
+            'const { spawn } = require("node:child_process")',
+            'const { writeFileSync } = require("node:fs")',
+            `const child = spawn(process.execPath, ["-e", ${JSON.stringify(child)}], { detached: true, stdio: "inherit" })`,
+            "child.unref()",
+            `writeFileSync(${JSON.stringify(file)}, String(child.pid))`,
+          ].join("\n"),
+        ])
+        yield* Effect.addFinalizer(() =>
+          Effect.promise(async () => {
+            const pid = Number(await fs.readFile(file, "utf8").catch(() => ""))
+            if (!pid) return
+            try {
+              process.kill(pid, "SIGKILL")
+            } catch {}
+          }),
+        )
+        const code = yield* handle.exitCode.pipe(
+          Effect.timeoutOrElse({
+            duration: "2 seconds",
+            orElse: () => Effect.die("exitCode waited for inherited output pipes"),
+          }),
+        )
+
+        expect(code).toBe(ChildProcessSpawner.ExitCode(0))
+        expect(yield* handle.isRunning).toBe(false)
+      }),
+    )
   })
 
   describe("error handling", () => {

packages/opencode/src/tool/shell.ts

@@ -1,4 +1,4 @@
-import { Effect, Stream } from "effect"
+import { Effect, Exit, Fiber, Stream } from "effect"
 import os from "os"
 import { createWriteStream } from "node:fs"
 import * as Tool from "./tool"
@@ -25,6 +25,7 @@ import { BashArity } from "@/permission/arity"
 export { Parameters } from "./shell/prompt"
 
 const MAX_METADATA_LENGTH = 30_000
+const POST_EXIT_OUTPUT_GRACE_MS = 500
 const CWD = new Set(["cd", "chdir", "popd", "pushd", "push-location", "set-location"])
 const FILES = new Set([
   ...CWD,
@@ -446,6 +447,7 @@ export const ShellTool = Tool.define(
       let cut = false
       let expired = false
       let aborted = false
+      let incomplete = false
 
       const closeSink = Effect.fnUntraced(function* () {
         const stream = sink
@@ -483,7 +485,7 @@ export const ShellTool = Tool.define(
           yield* Effect.addFinalizer(closeSink)
           const handle = yield* spawner.spawn(cmd(input.shell, input.command, input.cwd, input.env))
 
-          yield* Effect.forkScoped(
+          const output = yield* Effect.forkScoped(
             Stream.runForEach(Stream.decodeText(handle.all), (chunk) => {
               const size = Buffer.byteLength(chunk, "utf-8")
               list.push({ text: chunk, size })
@@ -554,6 +556,15 @@ export const ShellTool = Tool.define(
             yield* handle.kill({ forceKillAfter: "3 seconds" }).pipe(Effect.orDie)
           }
 
+          const outputComplete = yield* Fiber.await(output).pipe(
+            Effect.map(Exit.isSuccess),
+            Effect.timeoutOrElse({
+              duration: `${POST_EXIT_OUTPUT_GRACE_MS} millis`,
+              orElse: () => Effect.succeed(false),
+            }),
+          )
+          if (!outputComplete) incomplete = true
+
           return exit.kind === "exit" ? exit.code : null
         }),
       ).pipe(Effect.orDie)
@@ -565,6 +576,10 @@ export const ShellTool = Tool.define(
         )
       }
       if (aborted) meta.push("User aborted the command")
+      if (incomplete)
+        meta.push(
+          `shell process exited, but stdout/stderr did not reach EOF within ${POST_EXIT_OUTPUT_GRACE_MS} ms; a descendant process may still hold inherited pipe handles open`,
+        )
       const raw = list.map((item) => item.text).join("")
       const end = tail(raw, limits.maxLines, limits.maxBytes)
       if (end.cut) cut = true
@@ -588,6 +603,7 @@ export const ShellTool = Tool.define(
           output: last || preview(output),
           exit: code,
           truncated: cut,
+          ...(incomplete ? { outputIncomplete: true } : {}),
           ...(cut && file ? { outputPath: file } : {}),
         },
         output,

packages/opencode/test/tool/shell.test.ts

@@ -152,6 +152,15 @@ const withShell = <A, E, R>(item: { label: string; shell: string }, self: Effect
       }),
   )
 
+const kill = (file: string) =>
+  Effect.promise(async () => {
+    const pid = Number(await Bun.file(file).text().catch(() => ""))
+    if (!pid) return
+    try {
+      process.kill(pid, "SIGKILL")
+    } catch {}
+  })
+
 const each = (
   name: string,
   fn: (item: { label: string; shell: string }) => Effect.Effect<void, unknown, ShellTestServices>,
@@ -1077,6 +1086,44 @@ describe("tool.shell abort", () => {
     15_000,
   )
 
+  it.live(
+    "stops waiting when a descendant retains the output pipe",
+    () =>
+      Effect.gen(function* () {
+        const tmp = yield* tmpdirScoped()
+        const file = path.join(tmp, "parent.js")
+        const pid = path.join(tmp, "child.pid")
+        const child = 'setInterval(() => process.stdout.write("tick\\n"), 20)'
+        yield* Effect.promise(() =>
+          Bun.write(
+            file,
+            [
+              'const { spawn } = require("node:child_process")',
+              'const { writeFileSync } = require("node:fs")',
+              `const child = spawn(process.execPath, ["-e", ${JSON.stringify(child)}], { detached: true, stdio: "inherit" })`,
+              "child.unref()",
+              `writeFileSync(${JSON.stringify(pid)}, String(child.pid))`,
+              'console.log("parent done")',
+            ].join("\n"),
+          ),
+        )
+        const command = `${bin} ${quote(file.replaceAll("\\", "/"))}`
+        const started = Date.now()
+        const result = yield* runIn(
+          tmp,
+          run({ command: PS.has(sh()) ? `& ${command}` : command, timeout: 5_000 }),
+        ).pipe(Effect.ensuring(kill(pid)))
+
+        expect(Date.now() - started).toBeLessThan(3_000)
+        expect(result.output).toContain("parent done")
+        expect(result.output).toContain(
+          "shell process exited, but stdout/stderr did not reach EOF within 500 ms; a descendant process may still hold inherited pipe handles open",
+        )
+        expect(result.metadata.outputIncomplete).toBe(true)
+      }),
+    15_000,
+  )
+
   if (process.platform !== "win32") {
     it.live("captures stderr in output", () =>
       runIn(