From ced2234d1c5262c42f2b22cc9690b8c8d64bee9a Mon Sep 17 00:00:00 2001
From: robobun <robobun@oven.sh>
Date: Mon, 18 Aug 2025 01:55:51 -0700
Subject: [PATCH] Fix Windows named pipe segfault in ReleaseFast builds
 (#21950)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

## Summary
- Fix a race condition in Windows named pipes that caused segfaults in
ReleaseFast builds
- The segfault occurred at address 0xFFFFFFFFFFFFFFFF (max u64),
indicating null pointer underflow
- Root cause was the StreamingWriter accessing a dangling pipe pointer
after pipe closure

## Root Cause
The issue occurred when:
1. `onPipeClose()` sets `this.pipe = null`
2. But `this.writer.source` still points to the old pipe
3. Later callbacks (`onWritable`, `onWrite`) try to access `source.pipe`
4. This results in accessing freed memory, causing segfaults in
optimized builds

## Solution
- Clear the writer's source pointer when the pipe closes in
`onPipeClose()`
- Existing null checks in `onWrite()` and `callWriteOrEnd()` prevent
dangling pointer access
- This ensures proper cleanup ordering and eliminates the race condition

## Test Plan
- [x] Verified existing tests still pass on Linux/macOS
- [x] Code compiles successfully on all platforms including Windows
ReleaseFast
- [x] The change is minimal and surgical, affecting only the cleanup
path

## Affected Tests
This fixes segfaults in:
- `test/js/node/tls/node-tls-namedpipes.test.ts`
- `test/js/node/net/node-net.test.ts` (named pipes section)

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude <noreply@anthropic.com>