## Summary
Fixes issue #21677 where `Bun.serve()` was adding redundant Date headers
when users provided their own Date header in the response.
The root cause was that the HTTP server was writing user-provided Date
headers and then µWebSockets was automatically adding its own Date
header without checking if one already existed.
## Changes
- **Added Date header detection in `NodeHTTP.cpp`**: When a user
provides a Date header (either in common or uncommon headers), the code
now sets the `HTTP_WROTE_DATE_HEADER` flag to prevent µWebSockets from
automatically adding another Date header
- **Case-insensitive header matching**: Uses
`WTF::equalIgnoringASCIICase` for proper header name comparison in
uncommon headers
- **Comprehensive test coverage**: Added regression tests that verify no
duplicate Date headers in all scenarios (static responses, dynamic
responses, proxy responses)
## Test Plan
- [x] Added comprehensive regression test in
`test/regression/issue/21677.test.ts`
- [x] Tests verify only one Date header exists in all response scenarios
- [x] Tests fail with current main branch (confirms bug exists)
- [x] Tests pass with this fix (confirms bug is resolved)
- [x] Existing Date header tests still pass (no regression)
## Testing
The reproduction case from the issue now works correctly:
**Before (multiple Date headers):**
```
HTTP/1.1 200 OK
Date: Thu, 07 Aug 2025 17:02:24 GMT
content-type: text/plain;charset=utf-8
Date: Thu, 07 Aug 2025 17:02:23 GMT
```
**After (single Date header):**
```
HTTP/1.1 200 OK
Date: Thu, 07 Aug 2025 17:02:23 GMT
content-type: text/plain;charset=utf-8
```
🤖 Generated with [Claude Code](https://claude.ai/code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
* oooooh magic
* stuff
* run format
* ok
* yippee
* run the formatter back
* finish things up
* fix webkit
* more
* [autofix.ci] apply automated fixes
* fix compile
* fix compilation on windows, it seems to not work though :(
* update
* a
* v
* ok
* [autofix.ci] apply automated fixes
* OOPS
* bump bun to reduce ci bugs
* a
* js2native is done!
* improve array binding
* rebase
* some final stuff
* wasi fixes
* os
---------
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
* Use debug mode by default
* Enable build with assertions enabled
* Update cli.zig
* Update bun-linux-build.yml
* Fixes
* Fix `ASSERT_ENABLED`
* try this
* Update Dockerfile
* mimalloc debug
* Update CMakeLists.txt
* `Bun.deepMatch` - fix assertion failures
cc @dylan-conway, looks like we need to use `putDirectMayBeIndex` and check for `isCell` more carefully.
* Object.create support in code generator and callbacks wrapper
* Remove unused file
* zig upgrade
* zls
* Fix various errors
* Support `BuiltinAccessor` in create_hash_table script
* Fix assertion failure in `process.mainModule`
* Fix assertion failure in `onerror`
* Fix assertion failure when creating a Worker
* Fix asssertion failure when loading lots of files in bun test
* Fix assertion failure when termating a `Worker`
* Add helper for converting BunString to a WTFString
* Fix assertion failure in notifyNeedTermination
* Add more debug logs in `bun test`
* Fix compiler warning in usockets
* Fix assertion failure with `Worker` termination (another)
* Fix assertion failure in `coerceToInt64`
* Fix assertion failure in `BroadcastChannel`
* Fix assertion failure in `Headers.prototype.getAll`
* Fixes#7067
* Add heap analyzer label for CommonJS modules
* Fix assertion failure in module.require && module.require.resolve
* Remove unused code
* Fix assertion failure in debugger
* Fix crash in debugger
* Fix assertion failures in bun:sqlite
* Bump zig
* Bump WebKit
* Fix assertion failure in JSPromise::reject && JSInternalPromise::reject
* Fix assertion failure in ReadableStream::cancel
* Fix assertion failure in AsyncContextFrame::create
* Fix assertion failure in bun:sqlite
* Fix assertion failure in mocks
* Fix assertion failure in ServerWebSocket.close
* Fix assertion failure in N-API with subclasses
* [napi] Make promises cheaper
* undo
* Don't check for exceptions in ObjectInitializationScope
* Add separate entry point for test runner that doesn't generate code
* Don't deref builtin code
* Fix preload test
* Fix assertion failure in memoryUsage()
* Fix preload test, part 2
* Ensure that the env map for a Worker is empty after it is used
* The pointer for the Arena allocator used in parsing should not change
* Terminate thread on exit
* Start to implement scriptExecutionStatus
* Update worker.test.ts
* Fix Dirent.name setter
* Update settings.json
* Fix assertion failure in node:http
* Use correct value for `JSFinalObject::maxInlineCapacity`
* JSFinalObject::maxInlineCapacity x2
* Don't strip when assertions are enabled
* Make `m_wasTerminated` atomic
* Preserve directives in the transpiler
cc @ctjlewis
* Workaround assertion failure in ServerWebSocket.sendBinary and ServerWebSocket.sendText
* windows
* Buffer lockfile serialization in-memory
* PR feedback
* PR feedback
* PR feedback
* Windows
* quotes
* Update CMakeLists.txt
* Update bun-linux-build.yml
* Update bun-linux-build.yml
* Move this code to BunString.cpp
* Update BunString.cpp
---------
Co-authored-by: Jarred Sumner <709451+Jarred-Sumner@users.noreply.github.com>
* Update to latest SIMDUTF
* Fix issue with `Headers.toJSON` having an incorrect size set with set-cookie header
* [node:http] Fix `undefined` when multiple Set-Cookie headers are sent
* Count UTF8 byteLength for headers
This is not necessary, just being cautious.
* Update http-hello.node.mjs
* Be 100% sure the test isn't caching anything
* move this up
---------
Co-authored-by: Jarred Sumner <709451+Jarred-Sumner@users.noreply.github.com>
