uws: AsyncSocket::write takes a size_t length, so res.end() sends a body of 2 GiB or more whole by robobun · Pull Request #45341 · oven-sh/bun

robobun · 2026-10-15T13:12:23Z

Problem

res.end(body) in node:http with 2147483648 bytes or more sends Content-Length: N and then 2147483647 bytes. 'finish' fires, and a pipelined response lands in the missing bytes.
The loop in HttpResponse::internalEnd stops when AsyncSocket::write reports backpressure. For end() that write already queued its piece.
A refused head in front of an INT_MAX body aborts the process: the queue reservation adds two int values.

Fix

AsyncSocket::write, writeFramed and uncork take a size_t length. The int appears only at us_socket_write. A payload over INT_MAX leaves in pieces, and end() queues the rest once.
internalEnd calls write once: that line is the fix. Four other writers drop their own INT_MAX loops.
It sits on uws: BackPressure keeps room behind a growth, so framing does not copy a queued payload #45744, which merges first.
Verified: node-http-backpressure.test.ts and node-http-syscall-fault.test.ts, where two of three new tests fail on main.

Background

uSockets takes an int length per write. AsyncSocket, the uWS layer above it, queues what the kernel does not take.
An end() write accepts everything. An optional write (tryEnd()) leaves the rest with the caller.
Node.js does not promise whole delivery: libuv 1.53 rejects a write over 0x7ffff000 bytes. Bun delivers, as res.write() does.
Considered the one-condition fix in internalEnd: it copies a 2 GiB body twice.

Downsides

res.end(body) still copies what the kernel does not take: peak RSS 4,233,648 kB for 2^31 bytes of data, as on main.
Without uws: BackPressure keeps room behind a growth, so framing does not copy a queued payload #45744, res.write(3 GiB) then res.end() would peak at 6,328,752 kB against main's 4,233,964 kB. With it that row is 3,184,596 kB.
Two of the new tests skip below 10 GiB of memory. Nothing else found at or below INT_MAX: res.end("hi") runs 694 instructions in internalEnd, against 722.

Notes

Repro. A node:http server answers one request. A raw socket sends GET / HTTP/1.1 with Connection: close and counts the body bytes. Release builds of main 017b2439a7 and of this branch on #45744:

response	main	this PR
`res.end(Buffer)`, 2147483647 bytes	whole	whole
`res.end(Buffer)`, 2147483648 bytes	2147483647 bytes, `'finish'` fires	whole
`res.end(Buffer)`, 3221225472 bytes	2147483647 bytes	whole
`res.end(Buffer)`, 4294967296 bytes	2147483647 bytes	whole
`res.end(string)`, 2147483648 bytes of UTF-8	2147483647 bytes	whole
`node:https`, `res.end(Buffer)`, 2147483648 bytes	2147483647 bytes	whole
`Content-Length` by hand, `res.write(Buffer)`, 2147483648 bytes	whole	whole
`Bun.serve`, `new Response(Buffer)`, 2147483648 bytes	whole	whole

Origin and reach. No issue exists. A fuzz run found it. The reach is node:http res.end() with one chunk of 2^31 to 2^32 bytes under Content-Length framing, HTTP/1.0 or close-delimited framing. Bun.serve bodies go through tryEnd and are not affected.

Why the loop stopped. AsyncSocket::write(src, length, optionally) returns {length, true} for a write that is not optional: it sends what the kernel takes, queues the rest, and true means backpressure. internalEnd read true as "stop". The response offset stayed at INT_MAX, so markDone() did not run. On a keep-alive connection the next response then starts one byte early. The new res.end(body) test pipelines a second request and shows this on main: the body ends in ...ZZZH and the next response reads TTP/1.1 200 OK.

Upstream. uWebSockets has the same loop today (src/HttpResponse.h:203), and its manual says res.end "guarantees sending". #18479 made one res.write() over INT_MAX arrive whole and left this arm of end().

Node.js. Node hands the whole buffer to uv_write(). Node v26.3.0 has libuv 1.52.1: on Linux it sends all 2147483648 bytes, and both new backpressure tests give the same result there. libuv 1.53.0 rejects more than 0x7ffff000 bytes with UV_EINVAL (src/unix/stream.c:1331, libuv/libuv#5076), as macOS already did. nodejs/node#66282 updates Node to it. So Node will fail such a write where Bun delivers it. That is a deliberate difference: res.write() and Bun.serve already deliver any length, and no runtime reports 'finish' after it dropped bytes.

Commits. Four, on top of #45744.

AsyncSocket::write takes a size_t, internalEnd calls it once, and the reservation sum is a size_t. Tests: res.end(body) and the fault test. Both fail on main.
HttpResponse::write, tryWriteBody, spillBodyTail and writeBehindResponse make one call. They deliver whole on main. Test: res.write(body), which passes on main and guards the optional write that this commit rewrites.
uncork(src) reserves queue room for src only when src will be queued. For an optional write the reservation was up to INT_MAX bytes of unused capacity. No test observes the capacity.
writeStatus and writeHeader pass their lengths without an (int) cast. A review asked for it. No caller can observe it: these strings are far below INT_MAX.

An earlier revision carried nextLength hints for the framing behind a queued body. #45744 gives the queue that room itself, so the hints are gone from spillBodyTail, writeFramed and writeOverIntMax.

The abort. write() reserved room for the next write with (size_t) (length - written + nextLength), a sum of int values. uncork(src, INT_MAX) passes INT_MAX as nextLength, so a short flush of the corked head made the sum negative and the allocation failed. The fault test arms one send that returns 0 and calls res.end(Buffer.alloc(2 ** 31 - 1)). On main the server dies with AddressSanitizer: allocation-size-too-big in realloc under write_head_and_end.

Measurements. Release builds (ThinLTO) of main 017b2439a7, of #45744 alone, and of this branch on top of it, linux x64. strace, perf and valgrind are not installed in the container and cannot be installed, and the VM has no PMU (perf_event_open returns ENOENT). Send and mmap counts come from an LD_PRELOAD shim on the server process. Dynamic instruction counts come from gdb single-stepping one call, three calls each, all equal. The comparison is this branch against #45744, which is what this diff adds.

Size (size bun): text 106,740,470 to 106,739,702 (minus 768). data and bss are equal.
Symbols, per instantiation: AsyncSocket::write 672 to 653, writeFramed 1371 to 1347, uncork 228 to 204, internalEnd 1512 to 1509, HttpResponse::write 1308 to 961, tryWriteBody 945 to 719. New writeOverIntMax: 171 bytes, out of line. Once each: us_socket_buffered_js_write 2846 to 2541, AnyResponse::spill_body 406 to 280.
Instructions in internalEnd, one call: res.end("hi") 722 to 694, res.end() 611 to 605, res.end(64 KiB) 849 to 825, the res.end() behind a res.write(64 KiB) 338 to 335. In tryWriteBody for that res.write(64 KiB): 917 to 892.
Sends (send + sendmsg) on the server: 10,000 keep-alive res.end("hi") make 10,000, and 10,000 res.end() make 10,000, on both builds.
One res.end(2^31): 1 queue allocation and 1 send inside end() (the head and the first piece in one sendmsg). main: 2 sends, body cut. One res.end(2^32): 1 queue allocation, 1 send. One res.end(2^31 - 1): 2 sends on both.
res.write(N) then res.end() with a client that reads nothing until end() returned, end() called from the request's 'end' event. N = 1.5 GiB: 1 allocation and 1,611,920 kB peak, the same as uws: BackPressure keeps room behind a growth, so framing does not copy a queued payload #45744 alone, against 2 and 3,183,128 kB on main. N = 3 GiB: 1 allocation and 3,184,596 kB, against 2 and 4,234,308 kB on main. uws: BackPressure keeps room behind a growth, so framing does not copy a queued payload #45744 alone also makes 2 there (4,239,612 kB): main queues the body in two pieces, and the second piece grows the queue.
Server peak RSS (VmHWM) for res.end(body). Zero-filled 2^31: 2,136,388 kB (the body pages are never resident on Linux). 2^31 of data: 4,233,648 kB, which is the body plus the queue. Zero-filled 2^32: 4,233,496 kB, 3 GiB: 3,184,932 kB. res.write(2^31) with a callback: 41,868 kB.
Wall clock for 10,000 res.end("hi"), six interleaved runs against main: 395 to 637 ms on main, 360 to 504 ms here. The spread is larger than any difference.

What changed after the first round of reviews. An earlier revision of this PR queued a body over INT_MAX in one piece and carried nextLength hints so the framing behind it would fit. The hints reached three of five arms, and the rows they missed peaked at twice the body. A design review put the room in the queue itself: #45744 makes every growth of a uWS queue ask for 12 bytes more than the append needs. This PR now drops every hint it had: spillBodyTail, writeFramed and writeOverIntMax pass lengths only.

Tests.

res.end(body) runs the write that is not optional and the pipelined framing. The server is a child process and the body is a zero-filled Buffer, so the only large memory is the queue, about 2 GiB in the child. It is gated at 10 GiB like the 4 GiB case in buffer.test.js.
res.write(body) runs the optional write through tryWriteBody. The server keeps the Buffer by reference and copies nothing: its peak RSS is 41,676 kB. It is not gated.
Reduce node-http-backpressure test peak memory #31199 removed single 2 GB payloads from this file after 4.6 GB peaks were OOM-killed on 8 GB runners. Those payloads were filled and lived in the test runner. Here the res.end(body) peak is in a child, at 2.0 GiB, behind the gate.
The fault test needs a build with socket fault injection and the same 10 GiB.
On the debian 13 x64-asan lane the backpressure file ran 85 tests in 12.8 s. On a local debug ASAN build each 2 GiB test takes 6 to 33 s, and over 100 s on a freshly booted VM whose memory was never touched.

Suites on a debug ASAN build: node-http-backpressure.test.ts 85 of 85, node-http-syscall-fault.test.ts 7 of 7, node-http-pinned-write.test.ts 10 of 10, node-http-backpressure-max.test.ts (4 GiB chunked write) 1 of 1, node-http.test.ts 292 of 292, http-server-chunking.test.ts 13 of 13, serve-close-delimited-framing.test.ts 2 of 2. websocket-server.test.ts has the same 4 timeouts of 10 s as main on that build.

Not covered by a test: spillBodyTail, writeBehindResponse and writeRawInformational above INT_MAX. They reach the same arm as res.end(body). spillBodyTail ran by hand: res.write(3 GiB) then res.end() delivers all 3,221,225,489 bytes on the release build and on the debug ASAN build. Bun.serve with a body over INT_MAX has no test in CI.

Open PRs on the same lines.

node:http: make res._send() the stored head plus _writeRaw(), as in Node.js #44871 rewrites writeRawInformational with its own INT_MAX loop. After this PR it is one Super::write(data.data(), data.length()).
node:http: less work per request; events: emit() allocates no arguments array; faster header name lookup #45234 adds AsyncSocket::writeParts where this PR adds writeOverIntMax, and replaces the status and header writes. Both blocks stay. Its slow path can pass the size_t length. The fourth commit here edits four lines that node:http: less work per request; events: emit() allocates no arguments array; faster header name lookup #45234 deletes, so the second of the two to merge has a small conflict.
node:http: order req.socket.write() behind the corked response head #35018 adds an INT_MAX clamp in uws_async_socket_write.

Not in this PR.

res.end(body) by reference, as res.write() does it since node:http: hold large res.write() payloads by reference instead of copying into uWS backpressure #34511. It removes the copy.
WebSocket::send casts (int) message.length() for us_socket_write2 (packages/bun-uws/src/WebSocket.h:156). A message of exactly 2^32 bytes sends the frame header alone (run on 1.4.3-canary). It is a different write function.
HTTP/3: us_quic_stream_write takes an unsigned int. Http3Response.h:82, :183 and :247 cast to it, and src/uws_sys/quic/Stream.rs:83 panics on the conversion.
HttpResponse::write still splits above UINT_MAX, because the chunk size line takes an unsigned int. One allocation and one copy hold up to UINT_MAX on that path.
The Rust wrapper of us_socket_write2 passes usize lengths to int parameters (src/uws_sys/us_socket_t.rs:392).
At or below INT_MAX, a corked write() that does not fit the cork buffer goes to writeFramed, which takes no nextLength. A chunk tail behind an exact-fit queued body can still regrow the queue there, as on main. uws: fix O(n^2) BackPressure buffer compaction and reallocation on large writes #34023 measured that.

Self-reviewed: 15 concerns raised, 13 addressed. Not taken: a memory gate on res.write(body), because its server peaks at 41,676 kB. Not done here: the WebSocket::send cast, listed above. A later review raised four points. Two are commits 4 and 5. The memory cost is the first Downsides bullet. The test timeouts stay: one 2 GiB transfer takes up to 33 s on a debug build.

no test proof · iteration 0 · platform-specific test(s) that do not run on this machine, deferring to CI, which covers all platforms: test/js/node/http/node-http-syscall-fault.test.ts, test/js/node/http/node-http-backpressure.test.ts

robobun · 2026-10-15T13:12:39Z

^{Updated 7:29 PM PT - Oct 17th, 2026}

✅ @robobun, your commit 9e09c95b98604307417d951ce96fd7f3ffe63c8c passed in Build #127785! 🎉

🧪 To try this PR locally:

bunx bun-pr 45341

That installs a local version of the PR into your bun-45341 executable, so you can run:

bun-45341 --bun

robobun · 2026-10-15T13:12:58Z

Update: this change is on main through #46021 (9b4284f), together with the change of #45744. On a debug ASAN build of that commit, the three tests of this PR pass, and a body of 2147483648 bytes arrives whole. The tests are not on main. The text below describes main before that merge.

Reproduced on debug and release builds of main: a node:http server answers with res.end(Buffer.alloc(2147483648)), and a raw socket with Connection: close counts the body bytes. The client gets 2147483647 bytes and the response emits 'finish'. A body of 2147483647 bytes arrives whole. With a second request pipelined behind it, the next response starts one byte early.

With this PR the same runs deliver 2147483648 bytes, and bodies of 3 GiB and 4 GiB arrive whole. The new tests in test/js/node/http/node-http-backpressure.test.ts and node-http-syscall-fault.test.ts fail on main and pass here.

This PR sits on #45744, which makes a growth of a uWS queue ask for 12 bytes more than the append needs. Merge that one first. Measuring this branch found that a body over INT_MAX, queued in one piece, left no room for the framing behind it, so res.write(3 GiB) then res.end() on a stalled socket peaked at twice the body. #45744 fixes that for every uWS queue, and this PR drops the hints it carried for it. On the two together that row makes one queue allocation and peaks at 3,184,596 kB, against 4,234,308 kB on main.

PR: #45341

coderabbitai · 2026-10-15T20:43:03Z

Walkthrough

Socket write APIs now use size_t lengths and support payloads larger than INT_MAX. HTTP response paths use these APIs, and regression tests cover large response bodies, pipelined requests, and a stalled send.

Changes

Large HTTP response writes

Layer / File(s)	Summary
Size-based socket writes `packages/bun-uws/src/AsyncSocket.h`	Socket write methods use `size_t` lengths and return values. Oversized sources are written in bounded pieces. Optional writes stop when a piece is incomplete; non-optional writes queue the remaining source.
HTTP response integration and regression coverage `packages/bun-uws/src/HttpResponse.h`, `src/jsc/bindings/NodeHTTP.cpp`, `src/jsc/bindings/node/JSNodeHTTPServerSocket.cpp`, `test/js/node/http/node-http-backpressure.test.ts`, `test/js/node/http/node-http-syscall-fault.test.ts`	HTTP response paths pass full lengths to socket writes instead of splitting payloads at `INT_MAX`. Tests cover large fixed-length and chunked responses, pipelining, and a stalled send.

Suggested reviewers: jarred-sumner

Priority: ⬆️ High

Merge Risk: 🔵 Low · up to ccbbb

The large-response tests need their child-process setup and timeouts brought into line with repository rules. These are bounded test issues; no remaining response-corruption failure is established.

Pre-merge checks: 4

Check name	Status	Explanation
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.
Title check		The title clearly identifies the main change: widening AsyncSocket::write lengths so res.end() can send bodies of 2 GiB or more. It is specific and related to the changeset.
Description check		The description explains the problem, fix, verification steps, test results, limitations, and related changes. It does not use the exact template headings, but it provides the required information in …

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Actionable comments posted: 2

🪄 Fix comments: Fix CodeRabbit comments on this PR

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Inline comments:
Review comments at @test/js/node/http/node-http-backpressure.test.ts:
- Around line 2425-2440: Update the child server spawn in the backpressure test
to use bunExe() instead of process.execPath and pass bunEnv in the spawn
options, while preserving the existing stdio configuration.
- Line 2512: Remove the explicit timeout arguments from both large-body tests in
test/js/node/http/node-http-backpressure.test.ts at lines 2512 and 2527, and
from the test in test/js/node/http/node-http-syscall-fault.test.ts at line 369.
Keep the test bodies and other arguments unchanged.

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Reviewing files that changed from the base of the PR and between a407eae and ccbbba8.

📒 Files selected for processing: 6

packages/bun-uws/src/AsyncSocket.h
packages/bun-uws/src/HttpResponse.h
src/jsc/bindings/NodeHTTP.cpp
src/jsc/bindings/node/JSNodeHTTPServerSocket.cpp
test/js/node/http/node-http-backpressure.test.ts
test/js/node/http/node-http-syscall-fault.test.ts

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claude

Nothing blocking. The comments below are optional suggestions. There is no need to push a fix for them before merging.

Beyond the inline findings, I also checked the new (size_t) cast of the us_socket_write return at AsyncSocket.h:383 for a negative value becoming huge — us_socket_write clamps a failed send to 0 (socket.c:492) and the TLS path returns a non-negative byte count, so it is not affected. The ruled-out list also covered a socket closed from inside SSL_write during writeOverIntMax and the macOS exactly-INT_MAX writev total.

Extended reasoning...

The change widens AsyncSocket::write/writeFramed/uncork to size_t, adds writeOverIntMax, and replaces five INT_MAX chunk loops in HttpResponse.h, NodeHTTP.cpp and JSNodeHTTPServerSocket.cpp with single calls; it touches the shared socket write and backpressure queue path for all node:http and Bun.serve responses but no auth or crypto logic. Four inline findings were posted, so a human review is already indicated; this note only records the negative-return cast concern that was checked and ruled out.

Additional findings (outside the current diff — GitHub can't attach inline comments there):

🟡 packages/bun-uws/src/HttpResponse.h — nit: four callers still narrow a size_t length to int before passing it to the now size_t AsyncSocket::write, sweep:Super::write$[a-z]+\.data\($, $int$ [a-z]+\.length\). At HttpResponse.h:593, :602, :604 and :619 a status, key or value over INT_MAX bytes turns negative and then into a huge size_t, so write() reads far past the buffer instead of the base's silent drop. Fix: drop the (int) casts so every AsyncSocket::write caller in this file passes the size_t length unchanged, matching the casts this PR already removed at HttpResponse.h:300 and NodeHTTP.cpp:626. [also at: packages/bun-uws/src/HttpResponse.h:593 - nit: Stale (int) casts remain on Super::write calls now that the parameter is size_t. sweep:Super::write$[^)]*\(int$ — writeStatus and writeHeader at packages/bun-uws/src/HttpResponse.h:593, 602, 604 and 619 still truncate a string_view length through int before it widens back to size_t, which the PR's other callers dropped.]

Why this was flagged

The diff changes AsyncSocket::write to take size_t (packages/bun-uws/src/AsyncSocket.h:312) and removes (int) casts at HttpResponse.h:300, :568, NodeHTTP.cpp:626 and :631, but leaves Super::write(status.data(), (int) status.length()) at HttpResponse.h:593 and the same cast for key and value at :602, :604 and :619. A string_view longer than INT_MAX bytes becomes a negative int there, which converts to a size_t above 2^63 at the call. On the base the negative int reached us_socket_write and the send failed or was skipped; now write() takes the length > INT_MAX arm (AsyncSocket.h:365) and writeOverIntMax loops over pieces reading past the end of the string, a crash. The trigger (a response status or header over 2 GiB from user JS) is extreme, so this is a consistency nit about stale callers of the changed signature, not a practical defect.

Verification: nit. node:http res.writeHead(code, statusMessage) with a statusMessage whose UTF-8 form exceeds INT_MAX bytes. packages/bun-uws/src/HttpResponse.h:593 still reads Super::write(status.data(), (int) status.length());. A length > INT_MAX becomes a negative int, which sign-extends to a size_t above 2^63 at the new signature. So the actual outcome is a process abort. On the base the status was silently truncated.

robobun · 2026-10-17T00:42:06Z

The four (int) casts in writeStatus and writeHeader that the review found outside the diff are gone in 68e15d3. packages/bun-uws/src/HttpResponse.h has no (int) cast left, so every caller passes its size_t length to AsyncSocket::write unchanged.

claude

I re-reviewed after the two follow-up commits (68e15d3, bc43e9d) and found no new bugs; since this rewrites the uWS AsyncSocket write path that every HTTP response goes through, a human look is still worthwhile.

What was reviewed:

writeOverIntMax ordering under a cork: the first piece rides the cork buffer in one writev, a short cork flush lands in the queue before the rest of src is appended, and the second piece runs uncorked.
The corked >INT_MAX spill now routes through writeOverIntMax with nextLength, so spillBodyTail's chunk CRLF has reserved room; the <=INT_MAX corked path still goes through writeFramed without it (pre-existing shape).
internalEnd's data.empty() short-circuit matches the old loop, which never ran for empty data; every AsyncSocket::write/writeFramed/uncork caller in packages/bun-uws, src/jsc and src/uws_sys was grepped and none still casts to int.

Extended reasoning...

The change widens AsyncSocket::write, writeFramed and uncork to size_t lengths, adds writeOverIntMax to split a >INT_MAX src into INT_MAX-CORK_BUFFER_SIZE pieces and queue the remainder once for non-optional writes, and removes the INT_MAX chunking loops in HttpResponse internalEnd/write/tryWriteBody/spillBodyTail and in JSNodeHTTPServerSocket writeBehindResponse; two new subprocess tests cover a 2^31-byte res.end/res.write body and a fault-injected stalled head. It touches no auth, crypto or injection surface, but it is the hot write path for all HTTP/1 responses in both SSL and non-SSL variants. No new bugs were found this run and the follow-up commits address part of the earlier inline feedback, but the size and criticality of the rewritten path, the memory behavior of queuing a multi-GiB body, and the 2 GiB/120 s tests are judgment calls a maintainer should weigh, so defer rather than approve.

This review covers commit bc43e9d, which is no longer the latest commit on this pull request; later commits are not covered by it.

robobun · 2026-10-17T01:16:20Z

The review above covers bc43e9d6. The head is a8f2a0e027. Both commits have the same tree: git diff bc43e9d6 a8f2a0e027 is empty. Only the commit message changed, so that review covers the code at the head.

claude

Code review found no issues

No high-confidence issues detected in this change.

res.end(body) in node:http with 2^31 bytes or more sent Content-Length: N and then only 2147483647 bytes. The loop in HttpResponse::internalEnd stopped when AsyncSocket::write reported backpressure. For end() that write had already queued its piece, so the bytes behind the first INT_MAX piece were never sent or queued, and the response was never marked done: a pipelined response was written into the missing bytes. AsyncSocket::write, writeFramed and uncork now take and return size_t. The int of uSockets appears only where us_socket_write is called. A src over INT_MAX goes through writeOverIntMax: it offers pieces to the socket and queues the rest of a write that is not optional with one allocation. internalEnd calls write once. The room that write reserves for the next write was the sum of two ints. With a head that the socket does not take in front of a body of INT_MAX bytes, the sum overflowed and the allocation aborted the process. The sum is a size_t now. writeRawInformational, the trailer block and the automatic headers of node:http no longer cast their length to int.

HttpResponse::write, tryWriteBody, spillBodyTail and writeBehindResponse each cut a payload over INT_MAX into pieces with a loop of their own. All four deliver the whole payload on main. They now make one call, and the INT_MAX loops are gone from HttpResponse.h and JSNodeHTTPServerSocket.cpp. The res.write(body) test passes on main. It guards the optional write of a payload over INT_MAX, which this commit rewrites.

…eued uncork(src) flushes what is corked and then writes src. When the flush is short it asks the queue to reserve room for src too. An optional src is never queued: the caller keeps what the socket does not take. For such a write the reservation was up to INT_MAX bytes of unused capacity. No test observes the capacity of the queue.

The four casts to int were the last ones in HttpResponse.h. With a size_t parameter, a negative int would turn into a length near 2^64.

… 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>

Jarred-Sumner · 2026-10-20T21:43:32Z

This is Claude (an AI assistant) commenting on Jarred's behalf.

This fix went in with #46021, which is merged. Closing.

robobun assigned Jarred-Sumner Oct 15, 2026

github-actions Bot added the claude label Oct 15, 2026

robobun force-pushed the robobun/8bde8b6f/http-end-over-int-max branch from 648243d to ccbbba8 Compare October 15, 2026 19:48

robobun changed the title ~~uws: one AsyncSocket write for any length, so res.end() sends a body of 2 GiB or more whole~~ uws: AsyncSocket::write takes a size_t length, so res.end() sends a body of 2 GiB or more whole Oct 15, 2026

robobun marked this pull request as ready for review October 15, 2026 20:37

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Comment thread test/js/node/http/node-http-backpressure.test.ts

Comment thread test/js/node/http/node-http-backpressure.test.ts

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Comment thread packages/bun-uws/src/HttpResponse.h

Comment thread test/js/node/http/node-http-backpressure.test.ts

Comment thread packages/bun-uws/src/AsyncSocket.h

robobun force-pushed the robobun/8bde8b6f/http-end-over-int-max branch from bc43e9d to a8f2a0e Compare October 17, 2026 00:40

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robobun mentioned this pull request Oct 17, 2026

uws: BackPressure keeps room behind a growth, so framing does not copy a queued payload #45744

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robobun force-pushed the robobun/8bde8b6f/http-end-over-int-max branch from a8f2a0e to 910c3ef Compare October 17, 2026 13:39

robobun changed the base branch from main to robobun/8bde8b6f/uws-backpressure-tail-room October 17, 2026 13:39

robobun force-pushed the robobun/8bde8b6f/http-end-over-int-max branch from 910c3ef to b9b33da Compare October 17, 2026 13:46

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robobun force-pushed the robobun/8bde8b6f/http-end-over-int-max branch from b9b33da to ced9434 Compare October 17, 2026 22:11

robobun added 4 commits October 17, 2026 22:53

uws: writeStatus and writeHeader pass their length as a size_t

9e09c95

The four casts to int were the last ones in HttpResponse.h. With a size_t parameter, a negative int would turn into a length near 2^64.

robobun force-pushed the robobun/8bde8b6f/http-end-over-int-max branch from ced9434 to 9e09c95 Compare October 17, 2026 22:53

Jarred-Sumner mentioned this pull request Oct 19, 2026

Hardening: fix crashes across the runtime, bundler, dev server, shell and CLI #46021

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Jarred-Sumner closed this Oct 20, 2026

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uws: AsyncSocket::write takes a size_t length, so res.end() sends a body of 2 GiB or more whole - #45341

uws: AsyncSocket::write takes a size_t length, so res.end() sends a body of 2 GiB or more whole#45341
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