When using `res.setHeader('location', ...)` in Bun's Node.js-compatible HTTP
server, the header was being sent as `Location` (title-case) instead of
preserving the original lowercase `location`. This is because known HTTP
headers were being normalized to enum values, losing the original casing.
The fix adds an `originalName` field to `CommonHeader` that stores the
original header name when set via the Node.js HTTP API. When writing
response headers, the original name is used if available, otherwise
falling back to the default casing.
This makes Bun's behavior match Node.js, which preserves the original
casing of header names set via `setHeader()`.
Fixes#15578
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
- WTFMove → WTF::move / std::move: Replaced WTFMove() macro with
WTF::move() function for WTF types, std::move() for std types
- SortedArrayMap removed: Replaced with if-else chains in
EventFactory.cpp, JSCryptoKeyUsage.cpp
- Wasm::Memory::create signature changed: Removed VM parameter
- URLPattern allocation: Changed from WTF_MAKE_ISO_ALLOCATED to
WTF_MAKE_TZONE_ALLOCATED
---------
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
### What does this PR do?
- **Use `Latin1Character` instead of `LChar`**
- **Fix for
0875bc8f62**
### How did you verify your code works?
---
# WebKit Update Summary (September 2025)
## Overview
This document summarizes the major changes in WebKit/JavaScriptCore from
the September 2025 update. The update includes approximately 254
JSC-related commits with significant improvements to performance,
stability, and developer experience.
## Critical Bug Fixes
### Memory Safety
- **operationMaterializeObjectInOSR fix** (5c7aadfa0a96): Fixed
uninitialized Butterfly storage during OSR exits with sunk Array
allocations. This prevents potential crashes when arrays with holes are
materialized during OSR exit.
- **FTL materialization fixes** (a72d19840714, ed1e6fe03899): Added
missing internal object type handling in FTL materialization, improving
stability during optimization bailouts.
### Promise and Async Improvements
- **JSPromiseReaction object** (a1cb5e087a46, later reverted in
b0566a4db201): Initially introduced to improve promise reaction handling
but was reverted due to compatibility issues with Bun's modifications.
- **Async stack traces enhancements**:
- Added support for `Promise.any` in async stack traces (d9a997b3edaa)
- Added empty JSValue checking for async stack trace safety
(9d26223d4bcb)
- Promise.all support was added and later reverted due to performance
concerns
## Performance Optimizations
### JIT Compiler Improvements
- **B3 Immutable Loads** (570a3530f949, 62300f8db3d9): Added
immutability annotations and CSE optimizations for loads that can look
for targets in dominators
- **BBQ JIT enhancements**:
- Fixed callee-save register handling (c7ae05719045)
- Simplified F32 copysign operations (e0651af57025)
- **DFG optimizations**:
- Fixed RegExp constant folding with materialized NewRegExp nodes
(7b53a04a5afa)
- Improved RegExp object node handling in strength reduction
(eeb65e05095b)
### WebAssembly Improvements
- **WASM SIMD Support**:
- Added v128 support for IPInt call and tail-call instructions
(73f0c9d430cb)
- Implemented v128 support in local.get, local.set, global.get,
global.set (67d7bf15139a)
- Added x86_64 SIMD integer arithmetic and float instructions
- **WASM Memory Management**:
- Introduced WasmInstanceAnchor for better instance lifecycle management
(f9f1ed183bf7)
- Attached AbstractHeap to wasm memory access for better optimization
(f183c6f7def4)
- Added signal handling for null checks in wasm (bf18b5b709f3)
- **WASM Debugging**: Added LLDB debugging infrastructure for
WebAssembly (e03c10225cc8)
## API and Language Features
### Iterator Helpers
- Merged `Iterator.prototype.sliding` into `Iterator.prototype.windows`
(1d49e823702d)
- Optimized iterator next method calls using CachedCall (5ee92514060c)
### Math Extensions
- Improved performance of `Math.sumPrecise` implementation
(602294057337)
### Error Handling
- Enhanced error messages for for-of loops without Symbol.iterator
(0051bbf2491f)
## Infrastructure Changes
### Character Type Refactoring
- **LChar to Latin1Character rename** (63b97b511366, 1424f0687876):
Major refactoring replacing the `LChar` type with `Latin1Character`
throughout the codebase for better clarity
- Additional fixes for Latin1Character usage (711eab3243f0,
50bf8e6fd4ca, 88e29ab76aec)
### Build System
- Fixed builds with GCC 15.x (e33b18bc59d6)
- Added gitattributes for JSC test files (82c4cc796da6)
- Improved test runner with comprehensive verbose logging (7ef95c177a42)
- Added memory-limited annotations for tests using excessive memory
(b991cd17d612)
### Testing Infrastructure
- Improved handling of missing test executables (db1e3bbb3be2)
- Added support for non-customized ICU 74.2 in intl tests (c922a28b6642)
- Fixed various test configuration issues and timeouts
## Bun-Specific Modifications
### Preserved Customizations
- Maintained `BUN_JSC_ADDITIONS` for Bun-specific features
- Kept async context support for AsyncLocalStorage
- Preserved V8 heap snapshot compatibility layer
- Maintained custom inspector extensions
### Conflicts Resolved
- Successfully merged upstream changes while preserving Bun's event loop
integration
- Resolved conflicts in promise handling while maintaining Bun's async
behavior
- Fixed re-declaration issues with `isAsyncFrame` for async stack traces
## Breaking Changes and Reverts
### Reverted Features
1. **JSPromiseReaction object**: Reverted due to conflicts with Bun's
promise handling
2. **Promise.all async stack trace support**: Reverted due to ~4%
performance regression in JetStream3/doxbee-async benchmark
3. **Array.prototype.flat C++ implementation**: Reverted (reason not
specified in commit)
## Security Improvements
- Type safety improvements with uncheckedDowncast for Wasm::Callee
(48425afd643d)
- Added bounds checking and validation for Wasm array operations
(b5148db1c4c1)
- Improved memory safety with proper initialization of materialized
objects
## Platform Support
- macOS: Continued support for x64/arm64
- Linux: Maintained glibc/musl compatibility
- Windows: Preserved x64 support
- Fixed platform-specific alignment issues for x86_64 (94a60eb123c5)
## Notable Debugging Enhancements
- LLDB infrastructure for WebAssembly debugging
- Improved verbose command logging in test runners
- Enhanced stack trace capabilities for async functions
- Better error reporting for missing Symbol.iterator
## Performance Metrics
- Several memory optimizations for test execution
- JIT memory reservation size adjustments for debug builds
- Optimized iterator operations with cached calls
- Improved Math.sumPrecise performance
## Future Considerations
- The JSPromiseReaction implementation may need revisiting with adjusted
architecture
- Async stack trace support for Promise.all requires performance
optimization
- Continued work on WASM SIMD support for additional operations
## Migration Notes for Bun Team
1. **LChar usage**: All references to `LChar` have been replaced with
`Latin1Character`
2. **Promise handling**: The reverted JSPromiseReaction changes indicate
potential architectural conflicts that may need addressing
3. **Test configuration**: New memory-limited annotations should be used
for memory-intensive tests
4. **Build flags**: Ensure USE_BUN_JSC_ADDITIONS and USE_BUN_EVENT_LOOP
remain enabled
* Report memory allocated in fetch
* Memory size reporting to `Headers`
* Fixup memory reporting allocator
* Make these tests do more
* cleanup some of this
---------
Co-authored-by: Jarred Sumner <709451+Jarred-Sumner@users.noreply.github.com>
* fix valid status code range
* update path
* highwatermark option
* throw DOMException
* remove extra transpiler output
* more transpiler tests
* comment
* get index not quickly
* replace with `getDirectIndex`
* update abort test
* throw out of range status code
* promisify test fix
* move stdio test instance files
* working crypto tests
* allow duplicate set-cookie headers
* different formatting
* revert, fix will be in different pr
* it is called
* use min buffer size
* fix url tests
* null origin for other protocols
* remove overload
* add very large file test
* await
* coerce to int64
* 64
* no cast
* add todo blob url tests
* use `tryConvertToInt52`
This matches Deno's behavior (get() combines, iterator preserves the order, set and append combine), but implements both the Cloudflare Workers `getAll()` and the potential standard `getSetCookie` function. The rationale for choosing both is to better support libraries which check for `getAll` and also because `getSetCookie` seems a little confusing (names are hard)
This also makes `.toJSON` and JSON.stringify return an array for `Set-Cookie`
