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Status: fix and tests pushed, stacked on #37753 (this PR's base branch; rebased onto its current tip, so the diff here is only this PR's own commits). Reproduced by failing |
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I reviewed this PR and didn't find any bugs. Because it reworks cross-thread lifetime handling in unsafe Rust (the waker_error handshake, join-before-free, and the spawn() return-type change) and touches every platform's Waker::init, a human look would still be worthwhile.
Checked: ResetEvent provides the release/acquire so the waker_error write in thread_main happens-before the read in spawn(); on the success path the field is never written after init so the post-wait() read does not race with the running loop; thread.join() precedes heap::destroy so no use-after-free; bun_io::Error and bun_bundler::Error both derive Copy so the new Io variant and the by-value Option read are sound; the placeholder waker owns nothing on any platform so dropping it in destroy is harmless.
Extended reasoning...
Overview
Stacked on #37753. Replaces the panic!("Failed to create waker") in BundleThread::thread_main with an error handed back to the spawning thread through a new waker_error: Option<bun_io::Error> slot published by the existing ready_event. spawn() now owns both failure kinds (thread creation and waker creation), joins the failed thread before returning Err, and singleton::get() frees the allocation and leaves the singleton empty for a retry. bun_bundler::Error gains an Io variant, bun_io::Error::name() becomes pub, and WindowsWaker::init()'s return type is aligned with the POSIX wakers so the shared call site compiles everywhere. The existing LD_PRELOAD test is extended via describe.each to also fail eventfd() on the "Bundler" thread.
Security risks
None. This is error-path plumbing for an OS resource exhaustion condition; no user input reaches the changed code, no auth/crypto/permissions.
Level of scrutiny
High. The core of the change is a cross-thread handshake in unsafe Rust with raw-pointer field projections, followed by freeing an allocation the other thread was just using. That is exactly the class REVIEW.md flags most heavily (memory safety, thread affinity, ref lifetime). I traced the synchronization: thread_main writes waker_error before ready_event.set() (release), spawn() reads it after wait() (acquire), and on the error branch set() is the bundle thread's last access to *instance before it returns, so join() → destroy() is sound. On the success branch waker_error is only ever the None written by uninitialized() before the spawn, so reading it while the bundle thread runs its loop touches a disjoint, quiescent field via raw projection — no &Self is materialized. Async::Error is Copy, so the by-value Option read and the new #[from]/Copy derive on bun_bundler::Error hold.
Other factors
- The Windows return-type fix (
crate::Result→crate::error::Result) is a real cross-target compile fix that only surfaces now that the result is pattern-matched instead of unwrapped; the PR description sayscargo checkwas run for Windows/macOS/FreeBSD. - Test coverage is thorough (both entry points, both
throwmodes, retry-after-failure, repeated failure, HTML route) and reuses the #37753 harness viadescribe.each, which is the right shape. - The pre-existing kqueue leak on macOS mach-port failure is called out and deferred to #33845, and
IoRequestLoop::load()'s ownWaker::init()panic is a separate subsystem — both reasonable scope boundaries. - No prior reviews on the timeline.
The change looks correct to me, but unsafe cross-thread lifetime code plus a four-platform Waker surface is not something I'd approve without a human pass.
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Updated 12:28 PM PT - Aug 16th, 2026
✅ @robobun, your commit b4f211fc7e0ce20436e747c112cab9c903af4560 passed in 🧪 To try this PR locally: bunx bun-pr 37769That installs a local version of the PR into your bun-37769 --bun |
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I reviewed this PR and didn't find any bugs. Because it touches the cross-thread raw-pointer handshake in BundleThread::spawn/thread_main (unsafe field writes synchronized by ready_event, then join-before-free), a human look would still be worthwhile.
What was reviewed:
- The
waker_errorwrite-before-set()/ read-after-wait()ordering, and thatset()is the failing thread's last access to*instancebeforejoin()→destroy(). bun_io::ErrorisCopy, so the by-value read of(*instance).waker_erroris sound; the placeholder waker owns nothing, so dropping it indestroy()is harmless.WindowsWaker::init()return-type unification (crate::Result→crate::error::Result) so the sharedmatchcompiles on Windows; the per-thread-loop comment corrections matchuws_get_loop_with_native.- The shim's
eventfdhook keys onprctl(PR_GET_NAME) == "Bundler", which is set (via bothBuilder::nameandconfigure_named_thread) beforeWaker::init()runs.
Extended reasoning...
Overview
Stacked on #37753. Replaces the panic!("Failed to create waker") in BundleThread::thread_main with an error path: a new waker_error: Option<bun_io::Error> slot is written by the bundle thread before it set()s ready_event and returns; spawn() reads it after wait(), joins the thread, and returns Err. spawn() now returns Result<(), bun_bundler::Error> and absorbs the detach/join and errno-mapping that #37753 had put in singleton::get(), so the singleton has one uniform error path (free the allocation, leave the slot empty, fail the build via enqueue()'s existing completion hand-back). bun_bundler::Error gains an Io(bun_io::Error) variant; bun_io::Error::name() becomes pub; WindowsWaker::init()'s return type is unified with the POSIX wakers; and several comments describing WindowsLoop as process-global are corrected to per-thread. The test file is extended via describe.each to also intercept eventfd() on the "Bundler" thread.
Security risks
None. This is error-path plumbing for OS resource exhaustion (EMFILE/ENFILE) during Bun.build(); no untrusted input handling, auth, or crypto is touched.
Level of scrutiny
High. The core change is a cross-thread handshake over a heap allocation via raw pointers under unsafe: thread_main writes waker_error and set()s the event, spawn() wait()s and reads it, then join()s so the caller can free the allocation. I traced the ordering (ResetEvent is futex-backed and provides the happens-before; set() is the failing thread's last access; join() precedes destroy()), confirmed bun_io::Error derives Copy so the by-value read is a plain copy, and checked that the placeholder waker on every platform owns nothing whose drop would be unsound (Linux: sentinel fd; macOS: empty Box<[u8]> = no allocation; Windows: None). The ptr::write on the success path overwrites the placeholder without dropping it, which is also fine for the same reason. All of this looks correct, but it is exactly the memory-safety category the repo's review guidelines flag as most-blocked, and it is stacked on an unmerged PR, so a maintainer should confirm the design.
Other factors
The Windows init() return-type change from crate::Result (the write module's alias) to crate::error::Result (bun_io::Error) is required for the shared match Async::Waker::init() to typecheck across targets — the PR description says cargo check passes on Windows/macOS/FreeBSD. The comment-only edits in src/io/lib.rs and src/uws_sys/Loop.rs correct a factual inaccuracy (the uws loop is thread_local) that also justifies why the waker must be created on the bundle thread. The test extension reuses the existing five scenarios via describe.each, and the new eventfd hook is correctly scoped by thread name (set before Waker::init() runs).
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The x64-asan lane caught the shim intercepting JSC's own 2 MiB threads (WTF::Thread::create asserts on failure, so the process aborted). The base branch #37753 fixed that by only arming the shim around the calls that start the bundle thread, so I rebased onto its current tip and folded the waker mode into that structure: eventfd() is now intercepted only while armed and only on the thread named "Bundler". The rebase also picks up SystemErrno::from_io_error from the base instead of this branch's local errno mapping, and both modes now cover the ENOMEM path without the resource-limit hint. All 12 tests pass locally on the ASAN debug build. |
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I reviewed this PR and didn't find any bugs. Because it touches unsafe concurrent Rust (raw-pointer field projection, cross-thread handoff of waker_error via ResetEvent, thread join before freeing the allocation) and cross-platform waker code, a human look at the memory-safety reasoning would still be worthwhile.
What was reviewed:
waker_errorhandoff: write beforeready_event.set()/ read afterwait()—ResetEventis acquire/release (src/threading/ResetEvent.rs), andbun_io::ErrorisCopy, so the raw read is sound.- Success path: bundle thread never touches
waker_error, sospawn()reads the spawner's own initialNone— no race. thread.join()beforeErrreturn, sosingleton::get()'sdestroycannot race the exiting thread.WindowsWaker::init()return type now matches the POSIX wakers so the sharedmatchinthread_maintype-checks on all targets.
Extended reasoning...
Overview
Stacked on #37753. Converts the panic!("Failed to create waker") in BundleThread::thread_main (when eventfd/kqueue fails at the fd limit) into a build error surfaced through the same channel #37753 established for pthread_create failure. Adds a waker_error: Option<bun_io::Error> slot on BundleThread, changes spawn() to return Result<(), bun_bundler::Error> and to join the failed thread before returning, unifies the error path in singleton::get()/enqueue(), adds Error::Io(bun_io::Error) to the bundler error enum, aligns WindowsWaker::init()'s return type with the POSIX wakers, and corrects several comments describing the Windows loop as process-global (it is per-thread). The test file gains an eventfd() interposer keyed on the thread name and runs the existing 6 scenarios × 2 failure modes via describe.each.
Security risks
None. This is error-path plumbing for OS resource exhaustion; no untrusted input parsing, auth, or crypto.
Level of scrutiny
High. The core of the change is unsafe concurrent Rust: a value is written on the bundle thread via raw-pointer projection, published through a futex-backed ResetEvent, read on the spawning thread via raw-pointer deref, and then the allocation is freed after thread.join(). I verified the pieces (ResetEvent uses acquire/release; bun_io::Error and bun_bundler::Error derive Copy; on the success path the bundle thread never writes waker_error so the spawner's read of its own initial None cannot race; set() is the failing thread's last access to *instance and join() precedes the caller's free), and the SAFETY comments accurately describe each of these. But per the review guidelines, memory-safety-sensitive concurrent code with raw-pointer lifetime reasoning is exactly where a human should confirm the argument rather than rely on automated review alone.
Other factors
- Cross-platform: the
WindowsWaker::init()return-type change (crate::Result→crate::error::Result) is needed for the shared call site to compile on Windows; the PR description sayscargo checkwas run for Windows/macOS/FreeBSD. The comment corrections about the per-threadWindowsLoopare accurate (uws_get_loop_with_nativewraps a thread-local libuv loop). - Tests are thorough — both failure kinds × {reject,
throw:false, ENOMEM without hint, retry succeeds, retry keeps failing, HTML route 500→200}, using anLD_PRELOADshim that attributeseventfd()byprctl(PR_GET_NAME)(the thread name is set beforeWaker::init()). - The PR explicitly calls out the pre-existing kqueue leak on macOS mach-port failure as out of scope (#33845), which is the right boundary.
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Nothing changed since this review; it covers the rebased tip (82ebc6f), and CI for it is in flight. Agreed that the waker_error handshake in BundleThread::spawn/thread_main is the part that deserves a maintainer look; the PR body walks through the ordering argument (write before set(), read after wait(), join() before the allocation is freed). |
…annot create its waker The bundle thread creates its wakeup handle (eventfd on Linux, kqueue plus mach port on macOS) on the thread itself and panicked when that failed, which happens at the open-files limit. The spawning thread was blocked in ready_event.wait() at that point, so the first Bun.build() (or HTML route) in the process took bun down with "panic: Failed to create waker". thread_main now records the error in BundleThread::waker_error before setting ready_event and returns. spawn() reads it after the handshake, joins the thread and returns the error, so singleton::get() frees the allocation and reports it the same way it already reports a failed pthread_create: singleton::enqueue() fails the build with the reason in its log, and the next build tries to start the thread again. The waker still has to be created on the bundle thread because on Windows it binds the calling thread's libuv loop; WindowsWaker::init() now returns the same Result type as the POSIX wakers so the shared call site compiles on all targets. bun_bundler::Error gains an Io variant to carry the bun_io error.
…ing comments The field doc already says the waker holds the calling thread's loop; the SAFETY comments in wait()/wake(), the uv_loop() doc and WindowsLoop::get() still called it a process-global or default loop.
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Rebased onto the updated tip of #37753 (this PR is stacked on that branch, so that is where the conflicts came from, not main). The base had reworked two things this branch touched, and the resolution adopts both:
All 15 tests pass locally on the ASAN debug build; bun_bundler cargo check passes for the Windows and macOS targets. PR description updated to match. |
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Checked the conflict report: this branch merges cleanly into current main (verified with git merge-tree against 8326d1b), and so does the base branch, so there is nothing to resolve right now. The PR stays stacked on #37753; rebasing it onto main directly would fold everything main has gained into this PR's diff. When #37753 lands, this branch gets rebased onto main and CI re-runs. |
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I reviewed this PR and the automated bug-hunting pass found no issues. The waker_error handshake in BundleThread::spawn/thread_main looks sound to me (write before set(), read after wait(), join() before the allocation is freed, Async::Error is Copy so the by-value read is fine), but since it adds new unsafe cross-thread synchronization and changes spawn()'s ownership contract, a maintainer look is still worthwhile — as the author already noted.
Also checked: singleton::get() is the only caller of BundleThread::spawn so the return-type change is fully covered; the WindowsWaker::init() return-type fix (crate::Result at the io crate root is write::Result<_, bun_core::Error>, not error::Result) correctly unifies it with the POSIX wakers so waker_error_to_io's match compiles on Windows; the describe.each refactor keeps every existing pthread_create test intact and adds the waker mode alongside it.
Extended reasoning...
Overview
Stacked on #37753. Turns a panic (Failed to create waker) in BundleThread::thread_main into a build error when the bundle thread's waker (eventfd on Linux, kqueue+mach port on macOS) can't be created, typically at the open-files limit. Adds a waker_error: Option<bun_io::Error> slot published via the existing ready_event; spawn() now handles both detach-on-success and join-on-failure internally and returns std::io::Result<()>. Also fixes WindowsWaker::init()'s return type to match the POSIX wakers (crate::error::Result instead of crate::Result, which at the bun_io crate root is actually write::Result<_, bun_core::Error>), and corrects several comments describing WindowsLoop as process-global when it is per-thread. The test file gains an eventfd() interception in the LD_PRELOAD shim (keyed by thread name "Bundler") and reruns the six scenarios for both failure kinds via describe.each.
Security risks
None. This is error-path plumbing for an OS resource-exhaustion condition; no user-controlled input is parsed and no privilege boundary is crossed.
Level of scrutiny
High. The core change is new unsafe code implementing a cross-thread handshake over a raw *mut BundleThread: the bundle thread writes waker_error via addr_of_mut!, calls ready_event.set(), and returns; the spawner reads it after wait(), join()s, then the caller frees the allocation. The reasoning depends on ResetEvent providing acquire-release (it's futex-backed per the file's re-export comment), on Async::Error being Copy (verified in src/io/error.rs — it derives Copy), on the by-value (*instance).waker_error read not forming a &Self (it's a raw place read of a Copy field), and on set() being the failed thread's last access to *instance. All of this checks out, but per REVIEW.md this is squarely the "native code: memory safety" category that warrants maintainer sign-off. spawn()'s safety contract also changes (after Err, either no thread was started or one was started and joined), which singleton::get() — the only caller — handles correctly.
Other factors
- The test refactor was checked line-by-line: every pre-existing pthread_create test case is preserved inside the new
describe.each, and the one non-parametrized test (unnamed errno) correctly stays pthread_create-only with a comment explaining why. waker_error_to_iomapsSys(errno)viafrom_raw_os_error(errno as i32)soSystemErrno::from_io_errorinsingleton::enqueuerecovers it for the named message + hint;MachportCreationFailed/Unexpectedfall through tostd::io::Error::otherand take the OS-description arm. The Windows note (its waker cannot fail, and itsraw_os_errorspace is Win32 codes) is accurate.- The author already flagged the handshake as "the part that deserves a maintainer look" and reports CI green on 82ebc6f (192 jobs, x64-asan included); the tip b4f211f only adds the remaining per-thread comment fix in
src/io/lib.rs. - The PR description mentions
bun_bundler::Errorgaining anIovariant andbun_io::Error::name()becomingpub, neither of which is in the diff — those appear to be from an earlier iteration beforewaker_error_to_ioconverted tostd::io::Errorinstead. Not a concern for the code, just stale prose in the collapsed "Original description".
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Nothing changed since this review; it matches the current tip (b4f211f). On the one remark: the Error::Io variant and the bun_io::Error::name() visibility change are mentioned only inside the collapsed "earlier iterations" block, which is labeled as the superseded shape; the visible Fix section describes the current std::io::Error conversion. The handshake ordering (write before set(), read after wait(), join() before the free) remains the part for a maintainer to confirm. |
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#39864 rewrites |
… and CLI (#46021) ### What does this PR do? Hardening. This collects the open pull requests that fix a crash in Bun into one change, and fixes about 20 more crashes that had no pull request. "Crash" here means a segfault, a Rust panic, an abort, a failed assertion, memory corruption that a sanitizer reports, a native stack overflow, or an exception that ends the process and that the program can't catch. With this PR those cases throw a normal error, print a normal CLI error and exit 1, or just work. 306 pull requests are included: 227 whole, and 79 cut down to the crash fix where the rest was a refactor, a feature or a behavior change. Each one was checked against current `main` first. 45 more turned out to be fixed already, and 17 were duplicates. The full list is at the bottom. #### Crashes you could hit in normal use - **`bun build` with macros and a `.env` file crashed at random.** In a repro with many macro modules, more than a third of the builds crashed. Now 3,000 of 3,000 produce the right bundle. (#45960) - **`bun run` and `bunx` aborted if a signal arrived while the child was being spawned.** (#38926, #45965) - **`bun build --compile ./index.js ./public/*` panicked** if an embedded file's name wasn't valid UTF-8. - **A truncated or corrupted compiled executable** died with SIGBUS or a panic at startup. It now prints an error. (#31787, #38251, #41360) - **Dev server:** several `Option::unwrap()` panics after a failed or deleted import (#38046, #44744, #44746), a segfault when an `onLoad` plugin throws while another bundle is queued, a request that hung and then panicked with `bundle active`, and `server.stop()` that never resolved after a client aborted a waiting request. - **`Bun.serve`:** `server.fetch(url, { headers: new Headers() })` followed by a GC segfaulted (#40888). Routes were used after free after `server.reload()` with `tls.serverName` (#38636). - **`text()` and `json()` on a stream of string chunks** could abort the process, a regression in 1.4.0. (#44269) - **`Bun.Transpiler` with `exports.eliminate` or `exports.replace`** aborted on `export default 1` and on most re-export clauses. (#44137) - **A decorated `declare` field in a class expression** with `experimentalDecorators` panicked. (#38095) - **YAML and JSON5 files with a key that isn't a string** panicked with `--no-bundle` and in `Bun.Transpiler`. (#41827) - **`Bun.FileSystemRouter`:** reading `.params` segfaulted when a rejected route candidate left its parameters behind. (#39290, #39291) - **Native addons that call `uv_async_*`, `uv_timer_*`, `uv_idle_*`, `uv_prepare_*`, `uv_check_*`, `uv_queue_work` or `uv_cwd`** aborted with "unsupported uv function" on Linux and macOS. They're implemented now. (#36609, #39652, #39892) - **`--watch` and `--hot`** panicked when the system was out of inotify instances or file descriptors, or when the reload `exec` failed. They print an error now. (#39629, #39975, #44837) - **Paths longer than the path buffer** panicked in `bun install`, the resolver, the bundler, `--compile`, `tsconfig.json` `paths` and `baseUrl`, `package.json` `main` and `sideEffects`, `bun run --filter`, `bun pm diff`, source maps and snapshots. They're ordinary errors now, or they work. (#36340, #37529, #39104, #39650, #43067) - **A Worker that creates a `ShadowRealm` and imports `node:worker_threads` in it** segfaulted. - **`structuredClone` or `postMessage` of an X25519 key** gave an object that aborted the process when read. (#45624) - **`node:stream` web adapters and `node:http2`** could end the process with an exception that no handler could catch. (#45076, #45975) - **Windows:** a watcher panic in a burst of file changes (#44344), a segfault after the machine resumes from sleep (#33015), crashes in the shell's pipe reader (#39638, #43606), and addons that import from `node.exe` without the delay-load hook (#35618). Most of the rest needs unusual input: strings near the 2 GiB limit, buffers that another thread or a getter resizes or detaches in the middle of a call, `worker.terminate()` at a bad moment, running out of memory or file descriptors, very deep nesting, or hostile arguments to `bun:ffi`, `node:vm` and `bun:sqlite`. #### Behavior changes Things that didn't crash before and behave differently now: - `new` on native functions that aren't constructors throws a `TypeError`, as in Node: `util.types.*`, `buffer.isAscii`, `isUtf8`, `transcode`, `resolveObjectURL`, `bun:jsc` exports, `cc()` symbols. It used to return the call's result. They also stop printing as `[class hostname]`. (#34575) - `` $`cmd` `` throws `ERR_INVALID_ARG_VALUE` if an environment variable's name or value contains a NUL byte. It used to cut the value at the NUL. (#44981) - `cc()` functions throw a `TypeError` for arguments that used to reach C as garbage, and `read.*(ptr, NaN)` throws. (#37989, #38057, #40773) - As PID 1, `bun` exits with 128 + the signal number on Ctrl+C or `docker stop`. (#38877) - A `NODE_MODULE` addon that's already loaded by the main thread throws `ERR_DLOPEN_FAILED` when a live Worker loads it too, as in Node. (#39968) - An exception from a `node:vm` context reaches `uncaughtException` handlers. (#39992) `vm.constants.DONT_CONTEXTIFY` returns the real global proxy. (#34623) - `createPrivateKey` rejects an EC JWK whose private value doesn't match its public point. (#33752) - `@dec static {}` is a syntax error, as in TypeScript and esbuild. (#44883) - `clearTimeout` ignores 0 and negative ids, and timer ids no longer wrap. (#44771) - HEAD for a `Response` whose body is an S3-backed `Blob` reports the length that GET sends. (#44734) - `bun:sqlite` and `node:sqlite`: if `iterate()` left a write unfinished on a connection that has a hook, a user function or an authorizer, the write is finished on the connection's next call instead of during garbage collection. If the database is gone too, it's rolled back. - `bun test --bail` runs exit listeners and closes SQLite databases. (#39010) - Dev server: a request for a client script waits while a bundle is in flight (#42733), query strings reach framework routes (#33232), and a request gets a 500 instead of hanging when plugins fail (#36812). #### File formats - `.jsc` bytecode files get a 24-byte footer so they can be verified before decoding. Files from an older Bun are ignored and the source is parsed instead. (#39396) - `node:vm` `cachedData` gets an 8-byte checksum. A blob from an older Bun is rejected, which the API allows. (#32839) - The built-in modules section of a compiled executable changes from format 1 to 2 and carries an engine stamp. (#44907) #### Performance Measured in instructions per operation on release builds of this branch and its base, with an A/A run for the noise floor (0.0 to 0.2 %). No change: `Bun.serve`, `node:http`, WebSocket echo and publish, `bun build` of 3,807 modules, `bun run` with 2,000 imports, `readdir` / `Glob` / `fs.cp` over 23,689 entries, startup and RSS. The binary grows by 176 KB (0.17 %). | Faster | Instructions | | --- | --- | | WebSocket echo of a 1 MB non-ASCII text message | −72 % | | `Bun.inspect` of a large non-ASCII string | −39 % | | `Bun.markdown.html` on large non-ASCII input | −33 % | | `` $`cmd` `` with 300 environment variables | −6 % | | `fs.readSync` | −5 % | | `TextEncoder.encodeInto`, short ASCII strings | −4 % | | async `crypto.pbkdf2`, 16-byte inputs | −17 % | | Slower | Instructions | Why | | --- | --- | --- | | `cc()` calls | +5 to +51 per call | Argument count and type checks, and a check for `close()` (#37989, #38057, #43802, #44921). `dlopen()` calls don't change | | `process.env.X = v` | 38 → 593 per write | Writes aren't cached. Reads don't change (#38871) | | async `crypto.pbkdf2`, inputs of 1 KB or more | +4 to +9 % | Password and salt are copied (#40554) | | `bun build` with an object `--define` used thousands of times | +4.5 % | The object is copied per use (#45969) | #### Not included - Fixes that need a WebKit change: #39967, #42534, #42982, #43764, #43786, #44226. #42185 too: a typed array that has no `ArrayBuffer` yet can't be pinned, so `view.buffer.transfer()` during an async call can still free its bytes. Creating the `ArrayBuffer` up front costs 7 to 12 % on every async `fs` call, so the fix belongs in JSC: an `ArrayBuffer` created while the view is borrowed should start out pinned. - #45442 (`calc()` sums as a flat list): it changes minified output for real stylesheets to survive a `calc()` with 25,000 terms. It deserves its own review. - #40023 (Windows event loop redesign), #29928 (Windows exit path), #40534, #43963, #39571, #42904, #42834, #36355, #43266: refactors or features whose crash is already covered or isn't a crash. - The pull requests marked *(crash fix only)* below should stay open for their other half. ### How did you verify your code works? - **Tests.** Every fix has a test that fails on `main` (a release or an ASAN build) and passes on this branch, except where that isn't practical: code that only runs on Windows or macOS, inputs that need several GB of memory, and a few rare races. Those were checked by hand or by reading. - **Stored repro scripts.** 230 crash repros ran on release and ASAN builds of this branch and of `main`, side by side. Release: 88 no longer crash. ASAN: 106 no longer crash. None crashes that didn't before. What still crashes needs WebKit, is SQLite's own bug, or isn't a crash. The ASAN number is from a later commit than the release number. - **Dev server.** Because one fix makes requests wait, 2,171 generated programs ran random interleavings of edits, build errors, failing plugins, reloads, stops and disconnects with about 120,000 requests. No request hung, was answered twice or got a stale body. `main` hung in 82 of 1,161 programs. This also found the four dev server bugs listed above. - **Path helpers.** 336,000 boundary cases with buffers of exactly the computed size, and 12,003 random calls through 30 JS APIs on an ASAN build, compared with `main`. No sanitizer report, and the results match wherever `main` doesn't panic. - **What worked on 1.4.3 still works.** Reviewers compared behavior with 1.4.3 and took out what changed it: for example an output directory layout change for 9 or more entry points, a `server.reload()` change, and a changed error message for `import("file:///50%deposit.ts")`. - **Not run locally:** the Windows, macOS and FreeBSD code paths. CI compiles and tests them. ### Included pull requests **Bundler, transpiler, CSS, macros** (33) - #33881 bundler: allocate wrapper_ref for CommonJS modules with no non-hoistable statements - #35055 Bun.build plugins: handle filter RegExp flags beyond i/m/v - #37769 bundler: fail the build instead of panicking when the bundle thread cannot create its waker - #37784 bundler: copy inlined env values into the define arena, and give each Bun.build its own env copy *(crash fix only)* - #37858 bundler: fail the build instead of panicking when a plugin answer string cannot be converted - #38046 bun build --server-components: require the bun target and reject directives without a framework *(crash fix only)* - #38095 js_parser: fix panic on decorated declare/abstract fields in class expressions with experimentalDecorators - #38966 bundler: keep deep CSS, export star and composes graphs from overflowing the linker's stack - #38984 bundler: stop an export star ambiguity that loops back into a re-export chain from overflowing the stack - #39113 css: reject stylesheets of 2 GiB or more instead of aborting on an int cast - #39396 bundler: frame .jsc bytecode sidecars and verify them before decoding - #39855 bundler: join the work still on the pools before the bundle is torn down *(crash fix only)* - #41157 dev server: leave out an html link to a cached json module instead of panicking, and mark a new placeholder file stale - #41801 css: decode ill-formed UTF-8 to U+FFFD before tokenizing *(crash fix only)* - #41827 bundler: handle YAML and JSON5 keys that are not strings instead of panicking - #42242 js_parser: compress symbol link chains when following merged declarations - #42387 bundler: check receivers on the Bun.build plugin object and freeze its filters during a build - #42413 Bounds-check the InternalSourceMap window reader - #42657 macros: keep visited values alive so a reused address does not get another value's Expr - #43330 transpiler: do not print an empty `var` for a data file with no named export - #43355 bundler: fix "The memory limit has been exceeded." on large HTML entries - #43658 react-compiler: fix skipped functions and build aborts for dead code in a try body *(crash fix only)* - #44137 js_parser: fix four crashes of exports.eliminate and exports.replace - #44467 js_parser: replace skipped expressions with E::Missing and skip argument checks after a stack overflow - #44662 js_parser: walk binary chains on the heap and check the stack when rewriting decorated #private accesses - #44712 json5: reject sources of 2 GiB or more before parsing instead of aborting on an int cast - #44864 js_parser: walk conditional chains in import()/require() and define keys in a loop - #44883 js_parser: reject a decorator on a class static block, keep decorators out of the body of `declare global` *(crash fix only)* - #45045 Fix a segfault in new Bun.Transpiler(): re-point options.log after the constructor moves its Log - #45604 css: keep a url() in an at-rule prelude as written, and never print the resolved path of a url() *(crash fix only)* - #45748 bundler: put --banner/--footer in the bytecode ESM module record (flags from a parse, entries from JSC) *(crash fix only)* - #45960 macros: give each parse-worker macro VM its own env loader - #45969 js_parser: copy object and array defines per use, and copy the list of a lone JSX spread object *(crash fix only)* **`bun build --compile` and standalone executables** (3) - #31787 Don't crash at startup when a standalone executable's embedded graph is corrupted *(crash fix only)* - #38251 compile: exit with an error instead of SIGBUS when a standalone executable is truncated - #41360 standalone: check every offset in the embedded module graph before reading it **Resolver, module loading, plugins, paths** (25) - #32269 Bun.plugin: validate the namespace without a shared regex - #33183 bun:jsc: filter internal cells out of getProtectedObjects() - #34575 Don't register native functions as their own constructors - #36340 paths: size the thread-local join output buffers to MAX_PATH_BYTES on Windows - #37037 mock.module: reject async factory results that are not objects - #37065 bun:jsc: propagate JSONParse exceptions from samplingProfilerStackTraces - #37529 resolver: don't abort on a package.json sideEffects entry longer than the join buffer - #38179 node:module: throw instead of crashing when module._compile is set to a non-function - #38273 bun test: report a test file or preload the loader cannot resolve instead of exiting; keep the JUnit report valid U… *(crash fix only)* - #38732 paths: compute the common path of 9+ inputs with the same loop as fewer *(crash fix only)* - #39228 paths: strip C:\\ down to the drive root in without_trailing_slash_windows_path *(crash fix only)* - #39650 bun run --filter: stop panicking on workspace paths longer than the path buffer - #40186 resolver: stop deeply nested exports targets from overflowing the stack - #40258 resolver: publish Entry.abs_path through the per-entry mutex - #42183 node:module: reject a _resolveFilename override result that contains a null byte - #42401 node:module: accept any `this` in Module.prototype.require *(crash fix only)* - #42405 Bun.plugin: transpile a copy of typed array onLoad contents - #42414 node:module: end the Module._stat path at the first null byte - #42685 resolver: strip the trailing separator inside bust_dir_cache - #42735 Throw a RangeError instead of aborting when require.resolve paths or Worker preload outgrows its Vector - #43067 Report a path that does not fit a path buffer instead of aborting *(crash fix only)* - #44410 Fix a crash when code from a node:vm context reads require.cache or require.extensions - #44466 Trace the value an object or data module exports from its JSSourceCode - #45044 Bun.plugin: give onLoad's args.path its own bytes - #45117 cjs: do not call an `__esModule` getter during the annotation lookup **Dev server, `bun bake`, routers, `--watch` and `--hot`** (28) - #28793 Stop file watcher thread before Global.exit tears down memory *(crash fix only)* - #32143 bake: fix "Runtime file not found" panic in production builds of custom frameworks - #32443 watcher: don't free the Watcher in the spawn-to-start window *(crash fix only)* - #33232 bake: normalize the HTTP request-target before matching framework routes - #36812 bake: respond 500 and release both RequestContext refs when on_plugins_rejected / OOM drains a deferred framework r… - #37039 bake: report per-file print failures in the dev server instead of serving empty modules - #37276 hot_reloader: take entries_mutex for watcher-thread directory cache probes - #37444 bake: unregister Bake::SourceProvider from the source map table when it is destroyed - #39290 FileSystemRouter: match / against a root-level optional catch-all route *(crash fix only)* - #39291 FileSystemRouter: order dynamic routes by per-segment precedence like Next.js *(crash fix only)* - #39629 watch: report a failed watcher init as an error instead of a crash - #41185 bake: check for exceptions in the production build's module loader hooks and helpers - #41340 bake: skip the directory watch when the directory cannot be opened - #41617 Decide a directory watch event from the watchlist, not from the resolver's cached listing *(crash fix only)* - #42547 bake: re-arm the memory visualizer timer when it fires - #42733 dev server: make a client script request wait for the bundle in flight - #42828 bake: serve routes from a router root outside the project root instead of aborting or answering 404 - #42831 bake: resolve app.root and router roots through one checked join - #42836 bake: report route scan errors instead of aborting, and fail bun build --app on them *(crash fix only)* - #42840 dev server: map a router type's server entry point to the root route of that type - #42862 Bun.serve: return before a pending app.plugins setup() settles *(crash fix only)* - #42920 Do not create a mimalloc heap per FileSystemRouter, reload() or :nth-child(An-B) selector - #42934 dev server: register a client component without evaluating it - #43329 dev server: check the route bundle index of a client script URL before Index::init - #44249 fs.watch: read each directory and close it before descending - #44344 Windows: fix a watcher panic and lost events in a burst of file changes, and a --hot that stops watching a deleted… - #44744 dev server: answer a cached-file lookup only for a graph that bundled the file - #44746 dev server: keep an importer in its own graph when an import fails or is deleted **`Bun.serve`, sockets, HTTP, WebSocket, HTTP/2, QUIC, DNS** (28) - #42667 Reland "usockets(windows): keep a closed poll alive until the outer tick and libuv are done with it" (#39643) - #33015 fix(windows): segfault in uv__wake_all_loops after system resume *(crash fix only)* - #35761 node:quic: detach lsquic ctx pointers before the finalize-order sweep at worker VM teardown - #37082 Bun.serve: terminate FIFO/pipe file responses at EOF - #38024 dns: keep the c-ares uv_poll_t alive while its poll callback is on the stack (Windows) - #38636 serve: fix route use-after-free after reload() with tls.serverName *(crash fix only)* - #40888 server.fetch: copy a Headers argument instead of adopting the wrapper's pointer - #41337 Update lsquic to 4.9.4 and free unsent stateless resets on destroy *(crash fix only)* - #41384 usockets: hold a tick level for the whole of close_all - #41412 Windows: wait for close completions when closing a worker's uv loop - #41516 node:http2: handle an empty byte range in respondWithFile and respondWithFD - #41521 udp: report every binaryType from the getter, reject a dgram bind of the other family *(crash fix only)* - #42188 net: do not assert a two-character host in SocketAddress.parse - #42210 libuv(windows): keep a pipe's completed read counted until its read callback returns - #42334 fetch, Bun.serve: throw a RangeError for Headers that total 4 GiB or more *(crash fix only)* - #43738 usockets: close a socket whose resume the kernel refuses from the loop, not from the caller - #44338 node:http: response trailers travel with the end call of the response *(crash fix only)* - #44433 bake: make the parked-request list non-owning and look up the DevServer when a plugin load settles - #44533 node:quic: capture the handshake while the conn is alive, set the application at session creation - #44734 Bun.serve: answer HEAD for an S3-backed Blob body without an S3 stat - #44751 node:quic: close() waits only for opened streams, and lsquic sends no GOAWAY before HTTP/3 starts *(crash fix only)* - #44897 node:http2: throw instead of panic when the native setNextStreamID() misses its argument - #45076 node:http2: let close() and destroy() win over the refusal of a request - #45341 uws: AsyncSocket::write takes a size_t length, so res.end() sends a body of 2 GiB or more whole - #45522 node:http2: throw for an ALTSVC frame that is too long and for a pushPromise id that is not a stream id - #45676 node:quic: do not reset a stream lsquic has already finished - #45822 node:quic: name a stream in queued session events by a per-session key, not by its address - #45858 Bun.serve WebSocket: a message that does not fit in memory fails one connection, not the server *(crash fix only)* **Streams, Blob, S3, files, `node:fs`** (28) - #33845 io: propagate IoRequestLoop init failure instead of aborting *(crash fix only)* - #36365 prompt: drop debug_assert that rejects answers containing CR - #37090 Deliver FIFO bodies whose writer connects after the reader opens *(crash fix only)* - #38039 node:fs: stop fs.copyFile(src, "") from segfaulting on Windows - #38653 shell(cp): reject copying a directory into itself; walk cp trees without recursion - #39207 Convert scope-object receivers in the chaining functions and inspect.custom fallbacks - #39390 Blob deserialize: reject over-long paths, treat size >= MAX_SIZE as unknown, make slice() non-panicking - #39639 fetch: drop the upload and drain hop refs at VM teardown *(crash fix only)* - #40008 inspect hooks: copy user options with putDirectMayBeIndex *(crash fix only)* - #40462 Windows: FileSink.start({ path }) on a live writer: hand the writer a libuv fd and close the old source *(crash fix only)* - #41440 node:fs: pass the buffer to the read/readv/write/writev callback on error - #41584 Walk the timer pairing heap without recursion - #41608 native-readable: accept a stream with no native handle - #41710 JSSink write(): convert the chunk before resolving the native sink *(crash fix only)* - #42711 webstreams: bound the native recursion through a chain of tees or text streams - #43264 fetch: reject a file: URL whose path has an encoded NUL - #43709 s3: fix double free of a multipart part's bytes on worker terminate - #43950 streams: link readers and writers last, reject their promises as handled - #44036 PipeReader: label a chunk Eof only when the reader is at its end - #44181 streams: throw instead of aborting when a direct stream's text sink cannot take a string chunk - #44195 fs: validate POSIX directory records in one parser, report a malformed record as EIO *(crash fix only)* - #44269 streams: join the string chunks of a text consumer with one allocation - #44490 watch(windows): report a failed child spawn as an error instead of a panic *(crash fix only)* - #44954 process.stdout/stderr with no FileSink: write synchronously, reset after a failed write *(crash fix only)* - #45004 streams: leave a stream alone when a consumer fails to lock it - #45521 FileSink: throw ERR_ILLEGAL_CONSTRUCTOR from the constructor that script reaches by writer.constructor - #45738 s3: own the Blob store across the calls that run user JS - #45975 node:stream: do not touch the web controller after the web side is done **Node-API, V8 API, `bun:ffi`, `process.dlopen`** (15) - #36609 napi: implement uv_cwd on POSIX - #37989 bun:ffi: stop cc() from turning non-numeric pointer arguments into garbage pointers - #38057 bun:ffi: make cc() reject non-numeric i64/u64 arguments instead of passing garbage - #38425 bun:ffi: throw on an empty cc() source array instead of panicking - #39652 napi: implement uv_async_t, uv_queue_work and uv_default_loop on posix - #39805 Share one handle scope implementation between Node-API and the V8 API - #39892 napi: implement uv_idle_t, uv_prepare_t, uv_check_t and uv_timer_t on posix - #40144 bun:ffi: return undefined for a NULL napi_value from cc() and throw the scheduled napi exception - #40773 bun:ffi: add the full byteOffset in read.*, do not truncate it to int32 - #41704 napi: hand the thrown value to napi_get_and_clear_last_exception after napi_run_script - #42960 process.dlopen: run a V8 addon's init function after dlopen() returns - #43797 Fix debug assertion on an empty error message from a V8 addon or SQLite *(crash fix only)* - #43802 bun:ffi: throw a TypeError when a cc() symbol is called after its library's close() - #43940 napi: fail with ERR_BUFFER_TOO_LARGE instead of aborting above the ArrayBuffer limit *(crash fix only)* - #44921 bun:ffi: pad a short call to a cc() symbol with undefined **`node:vm`, workers, process, timers** (19) - #34623 node:vm: run DONT_CONTEXTIFY contexts directly against the real global - #32839 node:vm: reject invalid cachedData instead of crashing - #36921 error printer: clear the pending exception when formatting a non-Error uncaught value throws - #37270 error printer: one render per error, [Circular] under the key that closes the cycle - #38740 bun:test: give each VM its own fake clock *(crash fix only)* - #39864 Report a refused HTTP, bundle, IO or process waiter thread as an error instead of a crash *(crash fix only)* - #39992 process: deliver exceptions reported against a node:vm context to uncaughtException - #41654 node:vm: give each SourceTextModule request the import attributes of the declaration that created it *(crash fix only)* - #41739 Do not forward the inherited IPC channel to spawned scripts and tools - #41769 node:vm: stop compiling accepted cachedData, report each cachedData decode to the GC *(crash fix only)* - #42045 bun:test fake timers: never move the fake clock backwards - #42308 process.execve: throw instead of aborting for a string past the string limits - #42734 node:vm: report cachedData of 2 GiB or more as rejected instead of aborting - #42843 process.dlopen: reject a filename of PATH_MAX or more before dlopen() - #43500 process: accept SIGSTKFLT, SIGPOLL and SIGPWR, and emit every name of a signal number *(crash fix only)* - #44486 worker: stop the start sequence when a handler it calls stops the worker - #44771 timers: allocate ids from one 64-bit counter that never wraps - #44837 --hot: defer a reload during the preloads, and report a reload that cannot start - #44991 Fix a use-after-free in the VM ref-string intern for a string over the length limit **Shell, spawn, CLI, `bun test`, `bun install`** (31) - #30642 Fail fast at startup when simdutf has no usable implementation for this CPU - #34223 Fix four crashes: HTMLRewriter disturbed body, S3 locked-stream upload, ConnectionsList closed parser, shell brace… *(crash fix only)* - #34884 Guard the console and test-runner formatters against native stack overflow on deeply nested values *(crash fix only)* - #36584 process.chdir: publish an immutable cwd slice so no thread sees a torn cwd - #37135 bun test --parallel: hold the JSC API lock while draining the worker's final IPC backlog - #37527 shell(mv): report ENAMETOOLONG instead of panicking when a source name does not fit the path buffers - #37528 cli: stop aborting on absolute script paths longer than 1024 bytes on Windows - #38162 shell(cp): report ENAMETOOLONG instead of panicking on operands longer than the path buffers - #38205 shell(windows): report ENAMETOOLONG for operands that do not fit the path buffer - #39010 bun test: exit through the VM teardown path when --bail stops a run - #39104 bun test: report over-long coverage dir, JUnit outfile and bunfig root instead of panicking *(crash fix only)* - #39638 shell(cat): serve a second cat on the same stdin instead of hanging or panicking - #39641 usockets: report an out-of-descriptors event loop init as an error, not a crash *(crash fix only)* - #40181 shell: stop deeply nested if clauses from overflowing the parser stack - #40885 shell: throw instead of panicking when a ReadableStream is used as a redirect - #41155 ipc: send a queue item larger than 2 GiB in capped write requests - #42298 bun:test: print String objects with 16-bit storage correctly - #42577 bun:test: root the return values toHaveReturnedWith collects - #43606 shell(windows): report a failed pipe reader start through on_reader_error instead of leaking the subprocess *(crash fix only)* - #43838 node:cluster: read a worker's `ack` and `addressType` in the primary only when they are int32 - #44172 node:cluster: refuse a descriptor of the wrong kind in the primary *(crash fix only)* - #44185 node:cluster: one handle for each descriptor that workers name *(crash fix only)* - #44491 bun test: run every callback when native code leaves an exception pending *(crash fix only)* - #44694 shell mv: refuse to copy a directory into itself on the cross-device fallback - #44752 shell: take the command-substitution capture and drop its NUL bytes - #44981 shell: reject NUL bytes in .cwd() and .env() at the native setters - #45206 ini: reject a source of 2 GiB or more in Parser::parse instead of aborting on an int cast *(crash fix only)* - #45348 bun test: fix a segfault in .not.toThrow(Class) when Symbol.hasInstance accepts a thrown string, symbol or BigInt - #45649 shell: replace the output counters in mkdir, cp, ls and touch with the OutputTask queue - #45792 bun test: SIGKILL a spawnSync child that is still running 500 ms after the test's timeout *(crash fix only)* - #45910 create: own the remote-template response buffers instead of parking them in the CLI arena **Web APIs, Buffer, encoding, URL, crypto, zlib, SQLite, Redis and the rest** (96) - #29709 console: guard JSX/Proxy recursion in Bun.inspect (stack overflow SIGSEGV) - #30817 console.takeHeapSnapshot: clear prior snapshots before building - #30956 spawnSync: make signal-forwarding register/unregister safe for concurrent callers *(crash fix only)* - #31505 node:zlib: reject invalid brotli flush values at validation *(crash fix only)* - #31735 node:path: fix win32 drive-relative resolve on non-Windows hosts *(crash fix only)* - #32085 Fix crash when RedisClient onclose/onconnect is set to a non-callable - #32240 Fix BroadcastChannel custom inspect crash with numeric option keys - #33181 Reject interior null bytes in Bun.mmap, Glob.scan, and FileSystemRouter paths *(crash fix only)* - #33752 node:crypto: validate EC JWK private scalar matches public point in createPrivateKey - #34976 spyOn: install and restore through one writer that throws when the object refuses *(crash fix only)* - #35562 structuredClone: purify NaN in deserialized Date timestamp so getTime never returns a forged JSValue - #35618 napi(windows): load addons that import node.exe without win_delay_load_hook - #35757 Coerce later arguments before capturing input buffers in Bun.Transpiler and Bun.RedisClient - #37252 Report UTF-16 to UTF-8 encode counts through size_t so exactly 2^32 written bytes doesn't wrap to 0 - #37338 node:module: build require.cache without user-writable globals and propagate its exceptions *(crash fix only)* - #37340 redis: accept unsubscribe acks that arrive outside subscriber mode - #37370 Error.appendStackTrace: make appending an error's trace to itself a no-op - #37443 node:crypto: fix null deref when worker.terminate() lands during an EC JWK private key import - #37448 jsc: check for exceptions before using a stored constructEmptyArray result *(crash fix only)* - #38009 MessagePort: fix a heap-use-after-free in contextDestroyed(), release ref() when the last 'message' listener is rem… *(crash fix only)* - #38469 napi: settle or refuse async work queued during VM teardown instead of taking a ticket - #38708 Handle 16-bit module sources in the error preview, the new-position fix-up and the REPL *(crash fix only)* - #38821 process.env: make a failed env build throw instead of aborting (Windows 0xC0000409 on Bun.$ / Bun.sql / process.env… - #38871 process.env: coerce to string on every execution of an assignment, not just the first - #38877 cli: exit 128 + signo when bun cannot die from a re-raised signal (bun as container PID 1) - #38926 Clear the inherited signal mask at startup and exec children with an empty one *(crash fix only)* - #39382 Make a failed util.inspect load throw from custom inspect functions instead of aborting - #39481 Always create the error when a native error message exceeds the string length limit - #39651 performance: keep the user timing entry counts exact after clearMarks(name) and clearMeasures(name) - #39775 Turn seccomp SIGSYS traps into ENOSYS so the syscall fallbacks run on Android - #39968 process.dlopen: replay a non-context-aware V8 addon only while no other live VM owns it - #39975 watch: report a failed reload exec as an error instead of a panic *(crash fix only)* - #40346 Give Glob's native scan methods their own private names - #40554 node:crypto: copy password and salt for async pbkdf2 and scrypt - #40567 url: reject URL-encoded input over the WTF decode limit instead of aborting - #40577 url: throw a RangeError instead of aborting when URLSearchParams or FormData outgrows its Vector - #41073 Store array-index property names as indexed properties in native object builders - #41137 Write the sampling profiler report at exit from Bun, not JSC's atexit hook - #41365 webview: fail only the view when WebKit lacks initWithDirectory: - #41574 Decode a private copy of a JS buffer in the UTF-8 decoders *(crash fix only)* - #41652 console: read a BigInt depth option by value in console.dir - #41749 Startup: reopen fd 0-2 as /dev/null only when the fd is closed - #41819 Report an incoherent BUN_JSC_* option combination as a configuration error, not a crash *(crash fix only)* - #42158 webview: reject malformed Chrome replies instead of crashing - #42179 shell: clamp a `> ${buf}` redirect to the target buffer's live length - #42187 node:crypto: throw ERR_OUT_OF_RANGE for >2 GiB buffer arguments instead of aborting - #42191 URLPattern: throw instead of aborting when a pattern string passes the string limit - #42192 Copy WebAssembly.Memory bytes for native borrows that outlive the call *(crash fix only)* - #42198 Make Bun.$, Bun.sql, Bun.postgres and Bun.SQL custom value getters so reifying the Bun object passes exception chec… - #42203 node:fs: fs.read into a WebAssembly.Memory view writes into the block a grow freed - #42214 Headers: throw a RangeError instead of aborting when the set-cookie list cannot grow - #42218 Headers: throw instead of aborting when a value passes the string length limit - #42220 URLPattern: throw instead of aborting when the token list cannot grow - #42225 Throw ERR_STRING_TOO_LONG from Bun.wrapAnsi instead of aborting when the output passes the string length limit - #42226 Throw instead of aborting when a MIME string does not fit in a string *(crash fix only)* - #42237 Bun.Cookie: throw instead of aborting when the Set-Cookie string passes the string length limit - #42249 Copy a shared input before libdeflate compresses it in Bun.gzipSync and Bun.deflateSync - #42253 bun test: walk nested describe scopes without native recursion - #42259 Throw instead of aborting when a domainToASCII host passes the string length limit - #42310 Parse a private copy of a shared or resizable buffer in Bun.Transpiler, Bun.markdown, Bun.YAML and Bun.TOML *(crash fix only)* - #42312 YAML, JSON5, XML stringify: throw instead of aborting when the output passes the string length limit - #42318 Bound libdeflate's emit path so a racing input cannot overrun the output - #42338 inspector: check the type of process.argv in getModuleGraph - #42364 node:perf_hooks: do not truncate the monitorEventLoopDelay resolution to int32 - #42412 transpiler cache: reject an entry with no sourcemap section - #42479 worker_threads: do not abort when markAsUntransferable/markAsUncloneable gets a WebAssembly GC reference - #42517 EventTarget: skip a listener object that has no realm - #42518 fs.Stats: make the date accessors define the property like Object.defineProperty *(crash fix only)* - #42575 Stop natives from writing onto a foreign `this` with putDirect: process.ppid, require.cache, StringDecoder, the nat… *(crash fix only)* - #42631 JSStringView: pin the cell that owns the borrowed characters - #42660 bun_core: read /dev/urandom when getrandom(2) answers ENOSYS or EPERM - #42780 node:crypto: treat a name too long to convert to UTF-8 as unknown instead of aborting - #42782 node:crypto: throw ERR_OUT_OF_RANGE for a passphrase larger than INT_MAX bytes - #42856 url: do not abort when a host is too long for the IDNA conversion buffers - #42868 sqlite, console, process: do not abort on a string too long to convert to UTF-8 *(crash fix only)* - #42941 Bun.sliceAnsi: throw instead of aborting when the result passes the string length limit - #43058 Bun.serve: fix crash and cross-request 500 when inspecting a non-Response return value throws - #43904 JSC bindings: build property keys from a BunString through Bun::toIdentifier - #44124 Bun.Image: decode WebP into a Bun-owned canvas and read ICCP without the demuxer *(crash fix only)* - #44190 Convert scope-object receivers before Buffer read*/write* and vm.Script describe them - #44211 Stop getsockname(out), useFakeTimers() and the stream source pull() from writing onto a caller's object with putDirect - #44295 bun test --coverage: append a final newline to a text that lacks one *(crash fix only)* - #44360 rust-argon2: return OutOfMemory instead of aborting when the memory cost cannot be allocated - #44421 node:zlib: free zstd's workers before the dictionary they read - #44521 util.parseArgs: pick the default args start from a per-VM eval flag, as Node v26 does *(crash fix only)* - #44740 structured clone: tolerate a zero-sized shared WebAssembly.Memory in computeMemoryCost() - #44759 HTMLRewriter: park a suspended handler's token before the output flush - #44907 Builtins section format 2: an engine stamp says which buns compile its modules - #45188 Reject an oversized WebCrypto cipher output instead of aborting - #45354 Throw for a `file:` URL whose path is not UTF-8 on Linux and macOS, through one `fileSystemPath()` accessor *(crash fix only)* - #45608 ipc: refuse an over-long message before the receive buffer stores it - #45624 webcrypto: write the key type into the X25519 structured-clone record - #45625 node:sqlite: refuse session.close() and Symbol.dispose inside a SQLite callback - #45653 glob: a group with `?` or a class matches when an alternative takes 64 bytes or more - #45820 Bun.file, S3Client.file and Bun.write no longer keep a buffer path alive forever - #45832 `bun check`: fix a panic on `export *` without a module specifier, and a false error for one in parentheses ### Already fixed on `main`, or duplicates of a pull request above Already fixed: #27323 #30401 #31011 #31206 #31566 #31626 #31695 #31702 #31945 #32773 #34154 #34697 #34744 #34964 #35655 #35816 #36020 #36181 #36296 #36342 #36581 #36602 #36807 #36818 #36857 #37172 #37235 #37239 #37267 #37420 #37731 #37914 #38113 #38119 #38509 #38514 #38540 #38975 #39410 #40749 #41163 #41171 #42108 #43085 #43230 Duplicates: #45654 #29986 #33378 #36895 #37070 #37639 #38014 #39021 #41266 #42250 #42951 #43238 #44259 #45335 #45565 #45726 #45965 Fixes #5019 Fixes #6106 Fixes #10690 Fixes #10886 Fixes #13566 Fixes #14745 Fixes #15551 Fixes #20454 Fixes #21310 Fixes #29145 Fixes #30454 Fixes #30613 Fixes #30766 Fixes #32103 Fixes #32142 Fixes #32183 Fixes #32212 Fixes #39060 Fixes #42296 Fixes #42931 Fixes #43671 Fixes #44201 Fixes #44735 Fixes #44783 Fixes #45198 Fixes #45327 Fixes #45491 Fixes #45721 --------- Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
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This is Claude (an AI assistant) commenting on Jarred's behalf. This fix went in with #46021, which is merged. Closing. |
Problem
EMFILE/ENFILE), the firstBun.build()in a process, or the first non-HMR HTML route request inBun.serve, aborts bun withpanic: Failed to create waker/oh no: Bun has crashed. Reproduced on 1.4.0 and on bundler: fail the build instead of panicking when the bundle thread cannot be started #37753's branch.EMFILEa build or a server hits (opening a source file, accept) is already reported as an error; this was the one spot that took the process down.pthread_createof this thread; the diff here is only this PR's commits.Fix
spawn()returns it as astd::io::Error(an errno round-trips throughSystemErrno::from_io_errorinto the named message, the macOS mach-port failure takes the OS-description path), sosingleton::get()has a single error path for both failure kinds.Failed to start the bundler thread: EMFILE.plus an open-files hint forEMFILE/ENFILE, next to bundler: fail the build instead of panicking when the bundle thread cannot be started #37753'sEAGAINthread-limit hint.init()now returns the sameResulttype as the POSIX ones so the shared call site compiles on every target; on Windows it cannot fail and the new branch is never taken.LD_PRELOADtest from bundler: fail the build instead of panicking when the bundle thread cannot be started #37753 now also failseventfd()on the "Bundler" thread and runs its seven scenarios for both failure kinds (plus bundler: fail the build instead of panicking when the bundle thread cannot be started #37753's unnamed-errno case, which only the spawn can hit). The waker cases hit the panic without this change and pass with it on a debug (ASAN) build. Linux only; Windows and macOS targets arecargo checkonly.Background
Bun.build()and HTML routes inBun.serverun on one lazily started, process-wide "Bundler" thread. The first build starts it and later builds enqueue work onto it; starting it needs two OS resources, the thread (bundler: fail the build instead of panicking when the bundle thread cannot be started #37753) and its waker (this PR).eventfdon Linux and akqueueplus a mach port on macOS, so creating it costs a file descriptor and can fail withEMFILE/ENFILE; on Windows it wraps the thread's libuv loop and cannot fail.set()is visible to the spawner afterwait(); that is the channel the error travels through.uWS::Loop::get()isthread_localand the loop dies with its thread, so a waker created on the JS thread before the spawn would bind the wrong loop. That is why the waker is created on the bundle thread and the failure reported back.LD_PRELOADlibrary overridingpthread_createandeventfd, driven by a plan string with one letter per intercepted call (ffails with the limit errno,nwithENOMEM,uwith a code bun has no errno name for,slets it through). It recognises the bundle thread by aRUST_MIN_STACKstack size nothing else requests for the spawn, and by the thread name "Bundler" (set before the waker is created) for the eventfd.no test proof · iteration 1 · Platform-specific test(s) that do not run on this machine. Deferring to CI, which covers all platforms: test/bundler/bun-build-thread-spawn-failure.test.ts
Earlier iterations (superseded by rebases onto #37753's branch)
Two shapes this PR had before #37753's branch moved under it:
bun_bundler::Error::Io(bun_io::Error)variant. bundler: fail the build instead of panicking when the bundle thread cannot be started #37753 later switched its own reporting tostd::io::Errorend to end (so an OS code bun has no errno name for is reported as the OS describes it); this PR now converts the waker'sbun_io::Errorinto astd::io::Errorinsidespawn()instead, and the extra enum variant and thebun_io::Error::name()visibility change are gone.RUST_MIN_STACKvalue nothing else asks for; the eventfd override was keyed on the thread name from the start and keeps working unchanged.Original description:
Stacked on #37753 (this PR's base is that branch, so the diff here is only this PR's own commits). #37753 makes a failed
pthread_createfor the "Bundler" thread fail the build; this does the same for the other resource the thread needs to start.What
Once the bundle thread is running it creates the handle it sleeps on (
eventfdon Linux,kqueueplus a mach port on macOS). When that fails, which is what happens at the open-files limit (EMFILE/ENFILE), the firstBun.build()(or the first non-HMR HTML route request inBun.serve) in the process aborts bun:Repro (Linux): an
LD_PRELOADshim that makeseventfd()returnEMFILEon the thread named "Bundler" (the name is set before the waker is created, and no other thread with that name creates an eventfd), thenexits 134 with the panic above on 1.4.0 and on a debug build of #37753's branch. The test in this PR is that shim.
Cause
BundleThread::thread_mainunwrappedWaker::init()with a panic. At that point the spawning thread is blocked inready_event.wait()insidesingleton::get(), so nothing could turn the failure into an error.Why this should be a build error rather than stay an abort: running out of descriptors is an OS resource condition, not a broken invariant, and
Bun.build()has an error channel that every other resource failure inside a build already uses (a source file that cannot be opened at the same fd limit is a build error; #37738 and #37753 route the pool and the thread itself through it). The same holds for a server bundling an HTML route on demand: every otherEMFILEit hits (accept, open) is an error it recovers from once descriptors are freed, and this one spot took the process down. It is the same shape as #35185 (a helper thread that cannot start fails the operation that asked for it), and unlike #33850 it does not try to keep going without process-level infrastructure: nothing of the failed attempt is kept and the next build starts from scratch.Fix (original shape)
BundleThreadgets awaker_errorslot. WhenWaker::init()fails,thread_mainwrites the error there, setsready_eventas usual and returns; thatset()is its last access to the struct.spawn()reads the slot afterready_event.wait(). On success it detaches the thread as before; on failure it joins the thread (so the allocation can be freed) and returns the error, sosingleton::get()has a single error path: free the allocation, leave the slot empty so the next build tries again, and hand the error tosingleton::enqueue(), which fails the build through its normal completion exactly as bundler: fail the build instead of panicking when the bundle thread cannot be started #37753 does for a failed spawn.WindowsWaker::init()returned a differentResultalias than the Linux and macOS wakers (bun_core::Errorinstead ofbun_io::Error), which nothing noticed while the result was only ever unwrapped. It now returns the same type, so the shared call site compiles on every target. Its docs and SAFETY comments (andWindowsLoop::get()'s) also called theWindowsLoopa process-global or default loop; it is per thread (uWS::Loop::get()isthread_local, wrapping the thread's libuv loop, and it is freed when that thread exits), so those comments now say that and derive the pointer's lifetime from the bundle thread never exiting. The per-thread loop is also why the waker cannot simply be created on the spawning thread before the spawn: on Windows it would bind the JS thread's loop. Creating it on the bundle thread and reporting back keeps one code path for all platforms.Not changed: when the mach port cannot be created on macOS,
KEventWaker::init_with_file_descriptorleaks the kqueue it had already opened. That is pre-existing (until now the process died right after) and #33845 fixes it inbun_io.