Files
bun.sh/test/regression
robobun 668eba0eb8 fix(node:http): Fix ServerResponse.writableNeedDrain causing stream pause (#24137)
## Summary

Fixes #19111

This PR fixes a bug where `fs.createReadStream().pipe(ServerResponse)`
would fail to transfer data when ServerResponse had no handle
(standalone usage). This affected Vite's static file serving and other
middleware adapters using the connect-to-web pattern.

## Root Cause

The bug was in the `ServerResponse.writableNeedDrain` getter at line
1529 of `_http_server.ts`:

```typescript
return !this.destroyed && !this.finished && (this[kHandle]?.bufferedAmount ?? 1) !== 0;
```

When `ServerResponse` had no handle (which is common in middleware
scenarios), the nullish coalescing operator defaulted `bufferedAmount`
to **1** instead of **0**. This caused `writableNeedDrain` to always
return `true`.

## Impact

When `pipe()` checks `dest.writableNeedDrain === true`, it immediately
pauses the source stream to handle backpressure. With the bug,
standalone ServerResponse instances always appeared to need draining,
causing piped streams to pause and never resume.

## Fix

Changed the default value from `1` to `0`:

```typescript
return !this.destroyed && !this.finished && (this[kHandle]?.bufferedAmount ?? 0) !== 0;
```

## Test Plan

-  Added regression test in `test/regression/issue/19111.test.ts`
-  Verified fix with actual Vite middleware reproduction
-  Confirmed behavior matches Node.js

Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude <noreply@anthropic.com>
2025-10-27 15:24:38 -07:00
..