## Summary
This PR fixes multiple HTTP/2 protocol compliance issues that were
causing stream errors with various HTTP/2 clients (Fauna, gRPC/Connect,
etc.).
fixes https://github.com/oven-sh/bun/issues/12544
fixes https://github.com/oven-sh/bun/issues/25589
### Key Fixes
**Window Size and Settings Handling**
- Fix initial stream window size to use `DEFAULT_WINDOW_SIZE` until
`SETTINGS_ACK` is received
- Per RFC 7540 Section 6.5.1: The sender can only rely on settings being
applied AFTER receiving `SETTINGS_ACK`
- Properly adjust existing stream windows when `INITIAL_WINDOW_SIZE`
setting changes (RFC 7540 Section 6.9.2)
**Header List Size Enforcement**
- Implement `maxHeaderListSize` checking per RFC 7540 Section 6.5.2
- Track cumulative header list size using HPACK entry overhead (32 bytes
per RFC 7541 Section 4.1)
- Reject streams with `ENHANCE_YOUR_CALM` when header list exceeds
configured limit
**Custom Settings Support**
- Add validation for `customSettings` option (up to 10 custom settings,
matching Node.js `MAX_ADDITIONAL_SETTINGS`)
- Validate setting IDs are in range `[0, 0xFFFF]` per RFC 7540
- Validate setting values are in range `[0, 2^32-1]`
**Settings Validation Improvements**
- Use float comparison for settings validation to handle large values
correctly (was using `toInt32()` which truncates)
- Use proper `HTTP2_INVALID_SETTING_VALUE_RangeError` error codes for
Node.js compatibility
**BufferFallbackAllocator** - New allocator that tries a provided buffer
first, falls back to heap:
- Similar to `std.heap.stackFallback` but accepts external buffer slice
- Used with `shared_request_buffer` (16KB threadlocal) for common cases
- Falls back to `bun.default_allocator` for large headers
## Test Plan
- [x] `bun bd` compiles successfully
- [x] Node.js HTTP/2 tests pass: `bun bd
test/js/node/test/parallel/test-http2-connect.js`
- [x] New regression tests for frame size issues: `bun bd test
test/regression/issue/25589.test.ts`
- [x] HTTP/2 continuation tests: `bun bd test
test/js/node/http2/node-http2-continuation.test.ts`
---------
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
### What does this PR do?
Fixes#24007
Possibly fixes https://github.com/oven-sh/bun/issues/18902,
https://github.com/oven-sh/bun/issues/7412
Some filesystems (bind mounts, FUSE, NFS) don't provide `d_type` in
directory entries, returning `DT_UNKNOWN`. This caused glob and
recursive readdir to skip entries entirely.
## Problem
On Linux filesystems that don't populate `d_type` in directory entries
(bind mounts, FUSE, NFS, some ext4 configurations), `readdir()` returns
`DT_UNKNOWN` instead of the actual file type. This caused:
- `Bun.Glob` to skip files/directories entirely
- `fs.readdirSync(..., {recursive: true})` to not recurse into
subdirectories
- `fs.readdirSync(..., {withFileTypes: true})` to report incorrect types
## Solution
Implemented a **lazy `lstatat()` fallback** when `d_type == DT_UNKNOWN`:
- **`sys.zig`**: Added `lstatat()` function - same as `fstatat()` but
with `AT_SYMLINK_NOFOLLOW` flag to correctly identify symlinks
- **`GlobWalker.zig`**: When encountering `.unknown` entries, first
check if filename matches pattern, then call `lstatat()` only if needed
- **`node_fs.zig`**: Handle `.unknown` in both async and sync recursive
readdir paths; propagate resolved kind to Dirent objects
- **`dir_iterator.zig`**: Return `.unknown` for `DT_UNKNOWN` entries,
letting callers handle lazy stat
**Why `lstatat` instead of `fstatat`?** We use `AT_SYMLINK_NOFOLLOW` to
preserve consistent behavior with normal filesystems - symlinks should
be reported as symlinks, not as their target type. This matches [Node.js
behavior](https://github.com/nodejs/node/blob/main/lib/internal/fs/utils.js#L251-L269)
which uses `lstat()` for the DT_UNKNOWN fallback, and follows the lazy
stat pattern established in PR #18172.
### How did you verify your code works?
**Testing:**
- Regression test: `test/regression/issue/24007.test.ts`
- FUSE filesystem test: `test/cli/run/glob-on-fuse.test.ts` (reuses
`fuse-fs.py` from PR #18172, includes symlink verification)
- All existing glob/readdir tests pass
- **Verified in Docker bind-mount environment:**
- Official Bun: `0 files`
- Patched Bun: `3 files`
**Performance:** No impact on normal filesystems - the `.unknown` branch
is only hit when `d_type == DT_UNKNOWN`. The lazy stat pattern avoids
unnecessary syscalls by checking pattern match first.
---------
Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
## Summary
- When `bun install` encounters a stale lockfile with a `file:`
dependency path that differs from the package.json, it now shows which
dependency caused the issue instead of the misleading "Bun could not
find a package.json file to install from" error.
## Test plan
- Added regression test in `test/regression/issue/26337.test.ts`
- Verified test fails with system bun (`USE_SYSTEM_BUN=1 bun test
test/regression/issue/26337.test.ts`)
- Verified test passes with debug build (`bun bd test
test/regression/issue/26337.test.ts`)
Fixes#26337🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
## Summary
Fixes bytecode alignment in standalone executables to prevent crashes
when loading bytecode cache on Windows.
The bytecode offset needs to be aligned such that when loaded at
runtime, the bytecode pointer is 128-byte aligned. Previously, alignment
was based on arbitrary memory addresses during compilation, which didn't
account for the 8-byte section header prepended at runtime. This caused
the bytecode to be misaligned, leading to segfaults in
`JSC::CachedJSValue::decode` on Windows.
## Root Cause
At runtime, embedded data starts 8 bytes after the PE/Mach-O section
virtual address (which is page-aligned, hence 128-byte aligned). For
bytecode at offset `O` to be aligned:
```
(section_va + 8 + O) % 128 == 0
=> (8 + O) % 128 == 0
=> O % 128 == 120
```
The previous code used `std.mem.alignInSlice()` which found aligned
addresses based on the compilation buffer's arbitrary address, not
accounting for the 8-byte header offset at load time.
## Changes
- **`src/StandaloneModuleGraph.zig`**: Calculate bytecode offset to
satisfy `offset % 128 == 120` instead of using `alignInSlice`
- **`test/regression/issue/26298.test.ts`**: Added regression tests for
bytecode cache in standalone executables
## Test plan
- [x] Added regression test `test/regression/issue/26298.test.ts` with 3
test cases
- [x] Existing `HelloWorldBytecode` test passes
- [x] Build succeeds
Fixes#26298🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
## Summary
- Fixes the `setTimeout.clock` property not being properly deleted after
`jest.useRealTimers()` is called
- Previously, the property was set to `false` instead of deleted,
causing `hasOwnProperty` checks to return `true`
- This broke React Testing Library and other libraries that check for
fake timers using `Object.prototype.hasOwnProperty.call(setTimeout,
'clock')`
## Changes
- Added `JSValue.deleteProperty()` binding in Zig to call JSC's
`deleteProperty()` method
- Updated `setFakeTimerMarker()` in `FakeTimers.zig` to delete the
`clock` property when disabling fake timers
- Updated existing test in `test/regression/issue/25869.test.ts` to
verify correct behavior
- Added new regression test in `test/regression/issue/26284.test.ts`
## Test plan
- [x] Verified new test fails with system bun (before fix)
- [x] Verified new test passes with debug build (after fix)
- [x] Verified existing fake timer tests still pass
- [x] Verified test for issue #25869 passes with fix
Fixes#26284🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
### What does this PR do?
Fixes#5344Fixes#6356
### How did you verify your code works?
Some test coverage
---------
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Claude Bot <claude-bot@bun.sh>
## Summary
- The 'l' key in `bun update --interactive` now correctly selects the
package when toggling between Target and Latest versions
- Previously, pressing 'l' would toggle `use_latest` but not mark the
package as selected, causing the underline indicator to disappear and
the package not being included when confirming
## Test plan
- [x] Added regression test `test/regression/issue/24131.test.ts` that
verifies 'l' selects the package
- [x] Test fails with system bun (before fix) and passes with debug
build (after fix)
- [x] `bun bd test test/regression/issue/24131.test.ts` passes
Fixes#24131🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
## Summary
- Fixed `Bun.Terminal` callbacks (data, exit, drain) not being invoked
when the terminal is created inside `AsyncLocalStorage.run()`
## Root Cause
The bug was a redundant `isCallable()` check when storing callbacks in
`initTerminal()`:
1. In `Options.parseFromJS()`, callbacks are validated with
`isCallable()`, then wrapped with `withAsyncContextIfNeeded()`
2. Inside `AsyncLocalStorage.run()`, `withAsyncContextIfNeeded()`
returns an `AsyncContextFrame` object that wraps the callback + async
context
3. An `AsyncContextFrame` is NOT callable - it's a wrapper object. So
the second `isCallable()` check fails
4. Because the check fails, the callback is never stored via
`js.gc.set()`
5. When `onReadChunk()` tries to get the callback, it returns `null` and
the callback is never invoked
## Fix
Removed the redundant `isCallable()` check in `initTerminal()`. The
check was already performed in `parseFromJS()` before wrapping. Other
similar patterns (socket Handlers, Timer) simply store the wrapped
callback without re-checking.
Fixes#26286
## Test plan
- [x] Added regression test in `test/regression/issue/26286.test.ts`
- [x] Verified test fails with system Bun (times out because callback
never invoked)
- [x] Verified test passes with debug build
🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
## Summary
- Fixes TypeScript errors in the react-tailwind template's `build.ts`
when used with the template's strict `tsconfig.json`
## Test plan
- Added regression test `test/regression/issue/24364.test.ts` that
verifies TypeScript compilation passes
- Verified test fails with old template code and passes with fix
Closes#24364🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
## Summary
- Replaces empty placeholder executables with shell scripts that print
helpful error messages
- The scripts exit with code 1 instead of silently succeeding with code
0
- Helps users diagnose issues when installing with `--ignore-scripts` or
using pnpm
## Problem
When installing the `bun` npm package with `--ignore-scripts` or using
pnpm (which skips postinstall by default), the placeholder `bun.exe` and
`bunx.exe` files were empty, causing them to silently exit with code 0
and produce no output. This made it very difficult for users to
understand why bun wasn't working.
## Solution
The placeholder files are now shell scripts that:
1. Print a clear error message explaining the issue
2. Provide instructions on how to fix it (manually running postinstall
or reinstalling without `--ignore-scripts`)
3. Exit with code 1 to indicate failure
Example output when running the placeholder:
```
Error: Bun's postinstall script was not run.
This occurs when using --ignore-scripts during installation, or when using a
package manager like pnpm that does not run postinstall scripts by default.
To fix this, run the postinstall script manually:
cd node_modules/bun && node install.js
Or reinstall bun without the --ignore-scripts flag.
```
## Test plan
- [x] Added regression test that verifies the placeholder script
behavior
- [x] Test passes with `bun bd test test/regression/issue/24329.test.ts`
Fixes#24329🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
## Summary
- Fixed `assert.partialDeepStrictEqual` to correctly handle Map subset
checking
- Previously, Map comparison used `Bun.deepEquals` which required exact
equality
- Now properly checks that all entries in the expected Map exist in the
actual Map with matching values
Fixes#24338
## Test plan
- Added comprehensive test suite in
`test/regression/issue/24338.test.ts` covering:
- Basic subset checking (key2 in Map with key1 and key2)
- Exact match cases
- Empty expected Map
- Multiple matching entries
- Nested objects as values
- Failure cases when expected has more keys
- Failure cases when key is missing in actual
- Failure cases when values differ
- Nested Map values
- Non-string keys
🤖 Generated with [Claude Code](https://claude.ai/code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
## Summary
- Extracts credentials from WebSocket URL (`ws://user:pass@host`) and
sends them as Basic Authorization header
- User-provided `Authorization` header takes precedence over URL
credentials
- Credentials are properly URL-decoded before being Base64-encoded
Fixes#24388
## Test plan
- [x] Added regression test `test/regression/issue/24388.test.ts` with 5
test cases:
- Basic credentials in URL
- Empty password
- No credentials (no header sent)
- Custom Authorization header takes precedence
- Special characters (URL-encoded) in credentials
- [x] Tests pass with `bun bd test test/regression/issue/24388.test.ts`
- [x] Tests fail with `USE_SYSTEM_BUN=1 bun test` (confirming the bug
existed)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
## Summary
- Fix `fs.Dirent.isFIFO()` incorrectly returning `true` for unknown file
types (e.g., on sshfs/NFS mounts)
- Remove the `EventPort` check from `isFIFO()` since `EventPort = 0 =
Unknown`
- Add regression test for the fix
Fixes#24129
## Root Cause
In `NodeDirent.cpp`, the `isFIFO()` method was checking:
```cpp
type == static_cast<int32_t>(DirEntType::NamedPipe) || type == static_cast<int32_t>(DirEntType::EventPort)
```
Since `EventPort = 0` and `Unknown = 0` (they share the same enum
value), any file with unknown type (returned by filesystems like sshfs,
NFS, etc. that don't populate `d_type`) would incorrectly trigger
`isFIFO() === true`.
## Test plan
- [x] Regression test: `bun bd test test/regression/issue/24129.test.ts`
- [x] Existing Dirent tests: `bun bd test test/js/node/fs/fs.test.ts -t
"Dirent"`
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
## Summary
- Make `bun:ffi`'s TinyCC compiler check standard C compiler environment
variables
- Add support for `C_INCLUDE_PATH` (include paths) and `LIBRARY_PATH`
(library paths)
- Fixes compilation on NixOS and other systems that don't use standard
FHS paths
## Test plan
- [x] Added regression test `test/regression/issue/26249.test.ts` that
verifies:
- Single path in `C_INCLUDE_PATH` works
- Multiple colon-separated paths in `C_INCLUDE_PATH` work
- [x] Verified test fails with system bun (without fix)
- [x] Verified test passes with debug build (with fix)
- [x] Verified existing `cc.test.ts` tests still pass
Closes#26249🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
## Summary
- Fix multipart uploads using form-data + node-fetch@2 +
fs.createReadStream() being truncated
- Convert old-style Node.js streams (that don't implement
`Symbol.asyncIterator`) to Web ReadableStreams before passing to native
fetch
## Test plan
- [x] New tests in `test/regression/issue/26225.test.ts` verify:
- Multipart uploads with form-data and createReadStream work correctly
- Async iterable bodies still work (regression test)
- Large file streams work correctly
- [x] Tests fail with `USE_SYSTEM_BUN=1` and pass with debug build
Fixes#26225🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
## Summary
- Legal comments (`/*! ... */`) were preventing the `module.exports =
require()` redirect optimization from being applied to CommonJS wrapper
modules
- The fix scans all parts to find a single meaningful statement,
skipping comments, directives, and empty statements
- If exactly one such statement exists and matches the `module.exports =
require()` pattern, the redirect optimization is now applied
This fixes an issue where wrapper modules like Express's `index.js`:
```js
/*!
* express
* MIT Licensed
*/
'use strict';
module.exports = require('./lib/express');
```
Were generating unnecessary wrapper functions instead of being
redirected directly to the target module.
## Test plan
- [x] Added regression test in `test/regression/issue/3179.test.ts`
- [x] Verified test fails with system bun and passes with the fix
- [x] Tested manual reproduction scenario
Fixes#3179🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
## Summary
- When running `bun <file>` on a file with an unsupported type (e.g.,
`.css`, `.yaml`, `.toml`), Bun now shows a helpful error message instead
of the misleading "File not found"
- Tracks when a file is resolved but has a loader that can't be run
directly
- Shows the actual file path and file type in the error message
**Before:**
```
error: File not found "test.css"
```
**After:**
```
error: Cannot run "/path/to/test.css"
note: Bun cannot run css files directly
```
## Test plan
- [x] Added regression test in `test/regression/issue/1365.test.ts`
- [x] Test verifies unsupported files show "Cannot run" error
- [x] Test verifies nonexistent files still show "File not found"
- [x] Test fails with `USE_SYSTEM_BUN=1` and passes with debug build
Fixes#1365🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
## Summary
- Fixes the entry point wrapper to distinguish between Server
configuration objects and already-running Server instances
- When a Server object from `Bun.serve()` is exported as the default
export, Bun no longer tries to call `Bun.serve()` on it again
## Root Cause
The entry point wrapper in `src/bundler/entry_points.zig` checks if the
default export has a `fetch` method to auto-start servers:
```javascript
if (typeof entryNamespace?.default?.fetch === 'function' || ...) {
const server = Bun.serve(entryNamespace.default);
}
```
However, `Server` objects returned from `Bun.serve()` also have a
`fetch` method (for programmatic request handling), so the wrapper
mistakenly tried to call `Bun.serve(server)` on an already-running
server.
## Solution
Added an `isServerConfig()` helper that checks:
1. The object has a `fetch` function or `app` property (config object
indicators)
2. The object does NOT have a `stop` method (Server instance indicator)
Server instances have `stop`, `reload`, `upgrade`, etc. methods, while
config objects don't.
## Test plan
- [x] Added regression test that verifies exporting a Server as default
export works without errors
- [x] Added test that verifies config objects with `fetch` still trigger
auto-start
- [x] Verified test fails with `USE_SYSTEM_BUN=1` and passes with the
fix
Fixes#26142🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
## Summary
- Fixes the `handleProtocols` option not setting the selected protocol
in WebSocket upgrade responses
- Removes duplicate protocol header values in responses
## Test plan
- Added regression tests in `test/regression/issue/3613.test.ts`
- Verified using fetch to check actual response headers contain the
correct protocol
Fixes#3613🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
## Summary
Fixed `http.request()` and `https.request()` hanging indefinitely when a
GET request includes a body (via `req.write()`).
### Approach
Instead of adding a public `allowGetBody` option to `fetch()`, this PR
creates a dedicated internal function `nodeHttpClient` that:
- Uses a comptime parameter to avoid code duplication
- Allows body on GET/HEAD/OPTIONS requests (Node.js behavior)
- Is only accessible internally via `$newZigFunction`
- Keeps the public `Bun.fetch()` API unchanged (Web Standards compliant)
### Implementation
1. **fetch.zig**: Refactored to use `fetchImpl(comptime allow_get_body:
bool, ...)` shared implementation
- `Bun__fetch_()` calls `fetchImpl(false, ...)` - validates body on
GET/HEAD/OPTIONS
- `nodeHttpClient()` calls `fetchImpl(true, ...)` - allows body on
GET/HEAD/OPTIONS
2. **_http_client.ts**: Uses `$newZigFunction("fetch.zig",
"nodeHttpClient", 2)` for HTTP requests
## Test plan
- [x] Added regression test at `test/regression/issue/26143.test.ts`
- [x] Test verifies GET requests with body complete successfully
- [x] Test verifies HEAD requests with body complete successfully
- [x] Test verifies `Bun.fetch()` still throws on GET with body (Web
Standards)
- [x] Test fails on current release (v1.3.6) and passes with this fix
Fixes#26143🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: Ciro Spaciari <ciro.spaciari@gmail.com>
Co-authored-by: Ciro Spaciari MacBook <ciro@anthropic.com>
## Summary
- Fixes `bun completions` crashing with `BrokenPipe` error when piped to
commands that close stdout early (e.g., `bun completions | true`)
- The fix catches `error.BrokenPipe` and exits cleanly with status 0
instead of propagating the error
## Test plan
- [x] Added regression test that pipes `bun completions` to `true` and
verifies no BrokenPipe error occurs
- [x] Verified test fails with system Bun and passes with fixed build
Fixes#2977🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
## Summary
- S3 `File.presign()` was ignoring the `contentDisposition` and `type`
options
- These options are now properly included as
`response-content-disposition` and `response-content-type` query
parameters in the presigned URL
- Added `content_type` field to `SignOptions` and
`S3CredentialsWithOptions` structs
- Added parsing for the `type` option in `getCredentialsWithOptions()`
- Query parameters are added in correct alphabetical order for AWS
Signature V4 compliance
## Test plan
- [x] Added regression test in `test/regression/issue/25750.test.ts`
- [x] Verified tests pass with debug build: `bun bd test
test/regression/issue/25750.test.ts`
- [x] Verified tests fail with system bun (without fix):
`USE_SYSTEM_BUN=1 bun test test/regression/issue/25750.test.ts`
- [x] Verified existing S3 presign tests still pass
- [x] Verified existing S3 signature order tests still pass
Fixes#25750🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
## Summary
- Fixes bug where `fetch()` with mTLS would use the first client
certificate for all subsequent requests to the same host, ignoring
per-request `tls` options
- Corrects `SSLConfig.isSame()` to properly compare all fields (was
incorrectly returning early when both optional fields were null)
- Sets `disable_keepalive=true` when reusing cached SSL contexts to
prevent socket pooling issues
Fixes#26125
## Test plan
- [x] Added regression test `test/regression/issue/26125.test.ts`
- [x] Verified test fails with system Bun 1.3.6 (demonstrates the bug)
- [x] Verified test passes with patched build
🤖 Generated with [Claude Code](https://claude.ai/code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
## Summary
- Fixes the broken pipe behavior for `process.stdout.write()` to match
Node.js
- When writing to a broken pipe (stdout destroyed), the process now
properly exits with code 1 instead of 0
- EPIPE errors are now properly propagated to JavaScript via the
stream's error event
## Test plan
- [x] Added regression test `test/regression/issue/1632.test.ts`
- [x] Verified test fails with system bun (exit code 0) and passes with
debug build (exit code 1)
- [x] Verified `console.log` still ignores errors (uses `catch {}`) and
doesn't crash
- [x] Verified callback-based `process.stdout.write()` receives EPIPE
error
## Changes
1. **`src/io/PipeWriter.zig`**: Return EPIPE as an error instead of
treating it as successful end-of-file (`.done`)
2. **`src/shell/IOWriter.zig`**: Track `broken_pipe` flag when EPIPE is
received via `onError` callback, and propagate error properly
3. **`src/js/internal/fs/streams.ts`**: When a write fails without a
callback, emit the error on the stream via `this.destroy(err)` to match
Node.js behavior
Fixes#1632🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
## Summary
- Add colon (`:`) to the list of characters that require quoting in yarn
lockfile version strings
- This fixes yarn parse errors when using `workspace:*` dependencies in
monorepo setups
Fixes#3192
## Test plan
- [x] Added regression test that verifies `workspace:*` versions are
properly quoted
- [x] Test fails with system bun (before fix)
- [x] Test passes with debug build (after fix)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
## Summary
- When a module exports `globalThis` (e.g., `module.exports =
globalThis`), Bun's auto-serve detection incorrectly triggered because
`globalThis.fetch` is the Fetch API function
- Scripts that export globalThis (like `core-js/es/global-this.js`)
would start a development server on port 3000 instead of exiting
normally
- Added explicit check to skip auto-serve when the default export is
`globalThis` itself
Fixes#440
## Test plan
- [x] Added test case `test/regression/issue/440.test.ts` that verifies:
- `module.exports = globalThis` does not start a server
- `export default globalThis` does not start a server
- [x] Verified test fails with system Bun (without fix)
- [x] Verified test passes with debug build (with fix)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
## Summary
- Fix memory leak in YAML parser that caused segfaults after high-volume
parsing
- Added `defer parser.deinit()` to free internal data structures
(context, block_indents, anchors, tag_handles, whitespace_buf)
- Fixes#26088
## Test plan
- [x] Added regression test at `test/regression/issue/26088.test.ts`
- [x] Verified YAML parsing still works correctly with debug build
- [x] Ran subset of YAML tests to confirm no regressions
🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
## Summary
- Fixes#3657 - `fs.watch` on directory doesn't emit `change` events for
files created after watch starts
When watching a directory with `fs.watch`, files created after the watch
was established would only emit a 'rename' event on creation, but
subsequent modifications would not emit 'change' events.
## Root Cause
The issue was twofold:
1. `watch_dir_mask` in INotifyWatcher.zig was missing `IN.MODIFY`, so
the inotify system call was not subscribed to file modification events
for watched directories.
2. When directory events were processed in path_watcher.zig, all events
were hardcoded to emit 'rename' instead of properly distinguishing
between file creation/deletion ('rename') and file modification
('change').
## Changes
- Adds `IN.MODIFY` to `watch_dir_mask` to receive modification events
- Adds a `create` flag to `WatchEvent.Op` to track `IN.CREATE` events
- Updates directory event processing to emit 'change' for pure write
events and 'rename' for create/delete/move events
## Test plan
- [x] Added regression test `test/regression/issue/3657.test.ts`
- [x] Verified test fails with system Bun (before fix)
- [x] Verified test passes with debug build (after fix)
- [x] Verified manual reproduction from issue now works correctly
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
## Summary
- Fixed lazy-loaded chunks from dynamic imports not appearing in
`frontend.files` when using `--splitting` with `--compile` in fullstack
builds
- Updated `computeChunks.zig` to mark non-entry-point chunks as browser
chunks when they contain browser-targeted files
- Updated `HTMLImportManifest.zig` to include browser chunks from server
builds in the files manifest
Fixes#25628
## Test plan
- [ ] Added regression test `test/regression/issue/25628.test.ts` that
verifies lazy chunks appear in `frontend.files`
- [ ] Manually verified: system bun reports `CHUNK_COUNT:1` (bug), debug
bun reports `CHUNK_COUNT:2` (fix)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
## Summary
- CSS logical border-radius properties (`border-start-start-radius`,
`border-start-end-radius`, `border-end-end-radius`,
`border-end-start-radius`) were being silently dropped when processed by
the CSS bundler
- The bug was in `src/css/properties/border_radius.zig` where
`VendorPrefix{}` (all fields false) was used instead of `VendorPrefix{
.none = true }` when computing prefixes for logical properties
- This caused the properties to be dropped by a later `isEmpty()` check
since an empty prefix struct was returned
## Test plan
- [x] Added regression test `test/regression/issue/25785.test.ts`
- [x] Verified test fails with system Bun (`USE_SYSTEM_BUN=1 bun test`)
- [x] Verified test passes with fixed bun-debug (`bun bd test`)
Fixes#25785🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
## Summary
- Implements the `-l` (long listing) flag functionality for the shell
`ls` builtin
- The flag was being parsed but never used - output was identical to
short format
- Now displays proper long listing format: file type, permissions, hard
link count, UID, GID, size, modification time, and filename
## Test plan
- [x] Added regression test in `test/regression/issue/25831.test.ts`
- [x] Test passes with debug build: `bun bd test
test/regression/issue/25831.test.ts`
- [x] Test fails with system bun (confirming the bug exists):
`USE_SYSTEM_BUN=1 bun test test/regression/issue/25831.test.ts`
Example output with fix:
```
$ bun -e 'import { $ } from "bun"; console.log(await $`ls -l`.text())'
drwxr-xr-x 2 1000 1000 4096 Jan 12 15:30 subdir
-rw-r--r-- 1 1000 1000 11 Jan 12 15:30 file.txt
```
Fixes#25831🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
## Summary
- Fix a hang in sequential MySQL transactions where an INSERT is awaited
followed by a SELECT returned in an array
- The issue occurred because `handleResultSetOK`'s defer block only
called `queue.advance()` without flushing, causing queries added during
the JS callback to not be properly sent
- Changed to call `flushQueue()` instead of just `advance()` to ensure
data is actually sent to the server
Fixes#26030
## Test plan
- Added regression test `test/regression/issue/26030.test.ts` with three
test cases:
- `Sequential transactions with INSERT and returned SELECT should not
hang` - reproduces the exact pattern from the bug report
- `Sequential transactions with returned array of multiple queries` -
tests returning multiple queries in array
- `Many sequential transactions with awaited INSERT and returned SELECT`
- stress tests with 5 sequential transactions
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
## Summary
- Fixed a bug where named function expressions were not renamed when
their name shadowed an outer symbol that's referenced inside the
function body
- This caused infinite recursion at runtime when namespace imports were
inlined
- Particularly affected Svelte 5 apps in dev mode
## Test plan
- [x] Added regression test that reproduces the issue
- [x] Verified test fails with system bun and passes with fix
- [x] Ran bundler tests (bundler_regressions, bundler_naming,
bundler_edgecase, bundler_minify) - all pass
## Root cause
The bundler was skipping `function_args` scopes when renaming symbols.
This meant named function expression names (which are declared in the
function_args scope) were never considered for renaming when they
collided with outer symbols.
For example, this code:
```javascript
import * as $ from './lib';
$.doSomething(function get() {
return $.get(123); // Should call outer get
});
```
Would be bundled as:
```javascript
function get(x) { return x * 2; } // from lib
doSomething(function get() {
return get(123); // Calls itself - infinite recursion!
});
```
Instead of:
```javascript
function get(x) { return x * 2; }
doSomething(function get2() { // Renamed to avoid collision
return get(123); // Correctly calls outer get
});
```
Fixes#25648🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
## Summary
- Fixed MySQL VARCHAR/CHAR/TEXT columns with binary collations (like
`utf8mb4_bin`) being incorrectly returned as `Buffer` instead of
`string`
- The fix checks for `character_set == 63` (binary collation) in
addition to the BINARY flag to properly distinguish true binary types
Fixes#26063
## Root Cause
PR #26011 introduced a fix for binary column handling that checked
`column.flags.BINARY` to determine if data should be returned as
`Buffer`. However, MySQL sets the BINARY flag on VARCHAR/CHAR/TEXT
columns with binary collations (like `utf8mb4_bin`) even though they
should return strings.
The proper way to detect true binary types (BINARY, VARBINARY, BLOB) is
to check if `character_set == 63` (the "binary" collation), not just the
BINARY flag.
## Changes
1. **Text Protocol** (`ResultSet.zig:143-148`): Updated binary check to
`column.flags.BINARY and column.character_set == 63`
2. **Binary Protocol** (`DecodeBinaryValue.zig:154-156`): Added
`character_set` parameter and updated binary check
## Test plan
- [ ] Added regression test `test/regression/issue/26063.test.ts` that
tests VARCHAR, CHAR, and TEXT columns with `utf8mb4_bin` collation
return strings
- [ ] Test verifies that true BINARY/VARBINARY/BLOB columns still return
Buffers
🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
## Summary
- Fixed `bun install --frozen-lockfile` to use scope-specific registry
for scoped packages when the lockfile has an empty registry URL
When parsing a `bun.lock` file with an empty registry URL for a scoped
package (like `@example/test-package`), bun was unconditionally using
the default npm registry (`https://registry.npmjs.org/`) instead of
looking up the scope-specific registry from `bunfig.toml`.
For example, with this configuration in `bunfig.toml`:
```toml
[install.scopes]
example = { url = "https://npm.pkg.github.com" }
```
And this lockfile entry with an empty registry URL:
```json
"@example/test-package": ["@example/test-package@1.0.0", "", {}, "sha512-AAAA"]
```
bun would try to fetch from
`https://registry.npmjs.org/@example/test-package/-/...` instead of
`https://npm.pkg.github.com/@example/test-package/-/...`.
The fix uses `manager.scopeForPackageName()` (the same pattern used in
`pnpm.zig`) to look up the correct scope-specific registry URL.
## Test plan
- [x] Added regression test `test/regression/issue/026039.test.ts` that
verifies:
- Scoped packages use the scope-specific registry from `bunfig.toml`
- Non-scoped packages continue to use the default registry
- [x] Verified test fails with system bun (without fix) and passes with
debug build (with fix)
Fixes#26039🤖 Generated with [Claude Code](https://claude.ai/code)
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
### What does this PR do?
Previously, reactFastRefresh was silently ignored when target was not
'browser', even when explicitly enabled. This was confusing as there was
no warning or error.
This change removes the `target == .browser` check, trusting explicit
user intent. If users enable reactFastRefresh with a non-browser target,
the transform will now be applied. If `$RefreshReg$` is not defined at
runtime, it will fail fast with a clear error rather than silently doing
nothing.
Use case: Terminal UIs (like [termcast](https://termcast.app)) need
React Fast Refresh with target: 'bun' for hot reloading in non-browser
environments.
### How did you verify your code works?
Updated existing test removing target browser
## Summary
- Add `_idleStart` property (getter/setter) to the Timeout object
returned by `setTimeout()` and `setInterval()`
- The property returns a monotonic timestamp (in milliseconds)
representing when the timer was created
- This mimics Node.js's behavior where `_idleStart` is the libuv
timestamp at timer creation time
## Test plan
- [x] Verified test fails with `USE_SYSTEM_BUN=1 bun test
test/regression/issue/25639.test.ts`
- [x] Verified test passes with `bun bd test
test/regression/issue/25639.test.ts`
- [x] Manual verification:
```bash
# Bun with fix - _idleStart exists
./build/debug/bun-debug -e "const t = setTimeout(() => {}, 0);
console.log('_idleStart' in t, typeof t._idleStart); clearTimeout(t)"
# Output: true number
# Node.js reference - same behavior
node -e "const t = setTimeout(() => {}, 0); console.log('_idleStart' in
t, typeof t._idleStart); clearTimeout(t)"
# Output: true number
```
Closes#25639🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
## Summary
- Fixes handler context not being restored after minifying nested CSS
rules
- Adds regression test for the issue
## Test plan
- [x] Test fails with `USE_SYSTEM_BUN=1 bun test
test/regression/issue/25794.test.ts`
- [x] Test passes with `bun bd test test/regression/issue/25794.test.ts`
Fixes#25794🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Fixes#25862
### What does this PR do?
When a client sends pipelined data immediately after CONNECT request
headers in the same TCP segment, Bun now properly delivers this data to
the `head` parameter of the 'connect' event handler, matching Node.js
behavior.
This enables compatibility with Cap'n Proto's KJ HTTP library used by
Cloudflare's workerd runtime, which pipelines RPC data after CONNECT.
### How did you verify your code works?
<img width="694" height="612" alt="CleanShot 2026-01-09 at 15 30 22@2x"
src="https://github.com/user-attachments/assets/3ffe840e-1792-429c-8303-d98ac3e6912a"
/>
Tests
---------
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
## Summary
Fixes#25869
Two fixes to enable `jest.useFakeTimers()` to work with
`@testing-library/react` and `@testing-library/user-event`:
- Set `setTimeout.clock = true` when fake timers are enabled.
testing-library/react's `jestFakeTimersAreEnabled()` checks for this
property to determine if `jest.advanceTimersByTime()` should be called
when draining the microtask queue. Without this, testing-library never
advances timers.
- Make `advanceTimersByTime(0)` fire `setTimeout(fn, 0)` timers.
`setTimeout(fn, 0)` is internally scheduled with a 1ms delay per HTML
spec. Jest/testing-library expect `advanceTimersByTime(0)` to fire such
"immediate" timers, but we were advancing by 0ms so they never fired.
## Test plan
- [x] All 30 existing fake timer tests pass
- [x] New regression test validates both fixes
- [x] Original user-event reproduction now works (test completes instead
of hanging)
🤖 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>
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
## Summary
- Fixes#25903 - `Bun.write()` mode option ignored when copying from
`Bun.file()`
- The destination file now correctly uses the specified `mode` option
instead of default permissions
- Works on Linux (via open flags), macOS (chmod after clonefile), and
Windows (chmod after copyfile)
## Test plan
- [x] Added regression test in `test/regression/issue/25903.test.ts`
- [x] Test passes with `bun bd test test/regression/issue/25903.test.ts`
- [x] Test fails with `USE_SYSTEM_BUN=1 bun test
test/regression/issue/25903.test.ts` (verifies the bug exists)
## Changes
- `src/bun.js/webcore/Blob.zig`: Add `mode` field to `WriteFileOptions`
and parse from options
- `src/bun.js/webcore/blob/copy_file.zig`: Use `destination_mode` in
`CopyFile` struct and `doOpenFile`
- `packages/bun-types/bun.d.ts`: Add `mode` option to BunFile copy
overloads
🤖 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>
Fixes#25716
Adds support for a `reactFastRefresh: boolean` option in the `Bun.build`
JavaScript API, matching the existing `--react-fast-refresh` CLI flag.
```ts
const result = await Bun.build({
reactFastRefresh: true,
entrypoints: ["src/App.tsx"],
});
```
When enabled, the bundler adds React Fast Refresh transform code
(`$RefreshReg$`, `$RefreshSig$`) to the output.
Closes#8254
Fixes a data corruption bug in `Bun.write()` where files larger than 2GB
would have chunks skipped resulting in corrupted output with missing
data.
The `doWriteLoop` had an issue where it would essentially end up
offsetting twice every 2GB chunks:
- it first sliced the buffer by `total_written`:
```remain = remain[@min(this.total_written, remain.len)..]```
- it would then increment `bytes_blob.offset`:
`this.bytes_blob.offset += @truncate(wrote)`
but because `sharedView()` already uses the blob offset `slice_ = slice_[this.offset..]` it would end up doubling the offset.
In a local reproduction writing a 16GB file with each 2GB chunk filled with incrementing values `[1, 2, 3, 4, 5, 6, 7, 8]`, the buggy version produced: `[1, 3, 5, 7, …]`, skipping every other chunk.
The fix is to simply remove the redundant manual offset and rely only on `total_written` to track write progress.
## Summary
- Fixes dead code elimination producing invalid syntax like `{ ...a, x:
}` when simplifying empty objects in spread contexts
- The issue was that `simplifyUnusedExpr` and `joinAllWithCommaCallback`
could return `E.Missing` instead of `null` to indicate "no side effects"
- Added checks to return `null` when the result is `E.Missing`
Fixes#25609
## Test plan
- [x] Added regression test that fails on v1.3.5 and passes with fix
- [x] `bun bd test test/regression/issue/25609.test.ts` passes
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: Claude <noreply@anthropic.com>
## Summary
Fix several memory leaks in the compression libraries:
- **NativeBrotli/NativeZstd reset()** - Each call to `reset()` allocated
a new encoder/decoder without freeing the previous one
- **NativeBrotli/NativeZstd init() error paths** - If `setParams()`
failed after `stream.init()` succeeded, the instance was leaked
- **NativeZstd init()** - If `setPledgedSrcSize()` failed after context
creation, the context was leaked
- **ZlibCompressorArrayList** - After `deflateInit2_()` succeeded, if
`ensureTotalCapacityPrecise()` failed with OOM, zlib internal state was
never freed
- **NativeBrotli close()** - Now sets state to null to prevent potential
double-free (defensive)
- **LibdeflateState** - Added `deinit()` for API consistency
## Test plan
- [x] Added regression test that calls `reset()` 100k times and measures
memory growth
- [x] Test shows memory growth dropped from ~600MB to ~10MB for Brotli
- [x] Verified no double-frees by tracing code paths
- [x] Existing zlib tests pass (except pre-existing timeout in debug
build)
Before fix (system bun 1.3.3):
```
Memory growth after 100000 reset() calls: 624.38 MB (BrotliCompress)
Memory growth after 100000 reset() calls: 540.63 MB (BrotliDecompress)
```
After fix:
```
Memory growth after 100000 reset() calls: 11.84 MB (BrotliCompress)
Memory growth after 100000 reset() calls: 0.16 MB (BrotliDecompress)
```
🤖 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>
## Summary
Fixes#24593 - WebSocket segfault on Windows when publishing large
messages with `perMessageDeflate: true`.
Also fixes#21028 (duplicate issue).
Also closes#25457 (alternative PR).
**Root cause:**
On Windows, the C++ code was compiled against system zlib headers
(1.3.1) but linked against Bun's vendored Cloudflare zlib (1.2.8).
This version mismatch caused `deflateInit2()` to return
`Z_VERSION_ERROR` (-6), leaving the deflate stream in an invalid state.
All subsequent `deflate()` calls returned `Z_STREAM_ERROR` (-2),
producing zero output, which then caused an integer underflow when
subtracting the 4-byte trailer → segfault in memcpy.
**Fix:**
Add `${VENDOR_PATH}/zlib` to the C++ include paths in
`cmake/targets/BuildBun.cmake`. This ensures the vendored zlib headers
are found before system headers, maintaining header/library version
consistency.
This is a simpler alternative to #25457 which worked around the issue by
using libdeflate exclusively.
## Test plan
- [x] Added regression test `test/regression/issue/24593.test.ts` with 4
test cases:
- Large ~109KB JSON message publish (core reproduction)
- Multiple rapid publishes (buffer corruption)
- Broadcast to multiple subscribers
- Messages at CORK_BUFFER_SIZE boundary (16KB)
- [x] Tests pass on Windows (was crashing before fix)
- [x] Tests pass on macOS
🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
