fs: fail WriteStream fast-path write() with ERR_STREAM_DESTROYED after destroy

src/js/internal/fs/streams.ts

@@ -639,10 +639,10 @@ const kWriteMonkeyPatchDefense = Symbol("!");
 function writeFast(this: FSStream, data: any, encoding: any, cb: any) {
   if (this[kWriteMonkeyPatchDefense]) return writablePrototypeWrite.$call(this, data, encoding, cb);
 
-  // After end() the Writable contract requires write() to fail with
-  // ERR_STREAM_WRITE_AFTER_END and not reach the sink.
+  // After end()/destroy() the Writable contract requires write() to fail with
+  // ERR_STREAM_WRITE_AFTER_END / ERR_STREAM_DESTROYED and not reach the sink.
   const state = this._writableState;
-  if (state !== undefined && state.ending) {
+  if (state !== undefined && (state.ending || state.destroyed)) {
     return writablePrototypeWrite.$call(this, data, encoding, cb);
   }
 

test/js/node/child_process/child-process-stdio.test.js

@@ -1,6 +1,7 @@
 import { describe, expect, it } from "bun:test";
 import { bunEnv, bunExe } from "harness";
 import { execSync, spawn } from "node:child_process";
+import { once } from "node:events";
 
 const CHILD_PROCESS_FILE = import.meta.dir + "/spawned-child.js";
 const OUT_FILE = import.meta.dir + "/stdio-test-out.txt";
@@ -117,3 +118,51 @@ describe("process.stdin", () => {
     expect(result).toEqual("data: File read successfully");
   });
 });
+
+describe("child.stdin", () => {
+  it("write() after child 'close' returns false and calls back with ERR_STREAM_DESTROYED", async () => {
+    const child = spawn(bunExe(), ["-e", ""], {
+      env: bunEnv,
+      stdio: ["pipe", "ignore", "ignore"],
+    });
+    await once(child, "close");
+
+    const { promise, resolve } = Promise.withResolvers();
+    const ret = child.stdin.write("dropped", resolve);
+    const cbErr = await promise;
+
+    expect({
+      ret,
+      cbCode: cbErr?.code,
+      destroyed: child.stdin.destroyed,
+      writable: child.stdin.writable,
+    }).toEqual({
+      ret: false,
+      cbCode: "ERR_STREAM_DESTROYED",
+      destroyed: true,
+      writable: false,
+    });
+  });
+
+  it("write() after child 'exit' (before 'close') returns false and calls back with ERR_STREAM_DESTROYED", async () => {
+    const child = spawn(bunExe(), ["-e", "process.stdin.once('data', () => process.exit(0))"], {
+      env: bunEnv,
+      stdio: ["pipe", "ignore", "ignore"],
+    });
+    child.stdin.on("error", () => {});
+    await new Promise((resolve, reject) => {
+      child.once("error", reject);
+      child.stdin.write("go\n", err => (err ? reject(err) : resolve()));
+    });
+    await once(child, "exit");
+
+    const { promise, resolve } = Promise.withResolvers();
+    const ret = child.stdin.write("late", resolve);
+    const cbErr = await promise;
+
+    expect({ ret, cbCode: cbErr?.code }).toEqual({
+      ret: false,
+      cbCode: "ERR_STREAM_DESTROYED",
+    });
+  });
+});