[robobun]

Rulings wanted (Notes): @dylan-conway (connect() after destroy()), @cirospaciari (one hook).

Problem

• socket.write(chunk, cb) never calls cb when the peer resets while the write waits for the native drain. Bun: ["error ECONNRESET read","close"]. Node v26.3.0: ["error ECONNRESET read","write cb ECANCELED write","close"].
• Cause: SocketHandlers2.close (src/js/node/net.ts:1774) and SocketEmitEndNT (net.ts:1058) call self.destroy(er) on a read error. They return before the block that fails the parked write.

Fix

• _destroy takes the parked callback before the handle closes. It fails it with write ECANCELED, as Node does: behind 'error', ahead of 'close'.
• A destroyed socket gets no EOF: a plain destroy() no longer emits 'end' (from node:net: keep 'end' off a destroyed socket and report the read error behind a write in flight #43392).
• connect() settles a queued cancel first, so it cannot fail the new connection (usockets: tell a socket's holder it is gone exactly once, whoever closes it and whether or not it ever opened #44327).
• Verified: node-net.test.ts, node-tls-connect.test.ts under bun and Node 24+ (35 bun cases fail on main). Also Node's test-net-*, test-tls-*, test-http-*, test-https-*. Self-reviewed: 32 concerns raised, 24 addressed (Notes).

Background

• _write parks the stream callback in kwriteCallback while the native socket holds unsent bytes. In Node, libuv owns that write: uv_close fails it with UV_ECANCELED (uv__stream_destroy).
• Considered a fix in each close handler (net: invoke the pending write callback when a read error destroys the socket #33401, node:net: keep 'end' off a destroyed socket and report the read error behind a write in flight #43392). One hook in _destroy also covers destroy() and TLS.

Downsides

• A canceled callback gets ECANCELED a loop turn after destroy(), not ERR_SOCKET_CLOSED at once. After a reset, an unhandled write promise ends the process.
• node:http emits no 'finish' for a request that destroy(err) ended. for await over a destroyed socket rejects. Both as in Node.
• No write in flight: _destroy pays 1 call, 2 branches, 1 property read. Debug bundle: +1,153 bytes.

Notes

Two rulings that this PR needs.

• dylan-conway: connect() after destroy(). usockets: tell a socket's holder it is gone exactly once, whoever closes it and whether or not it ever opened #44327 completes a canceled connect request at once. Its comment in connectError says why: "Not deferred here: it would land on a connect() made right after destroy() and fail that one." The cancel of a write cannot be completed at once (see "Why the cancel waits for the handle"). So this PR keeps it for the close phase, and connect() settles a cancel that is still queued before it dials. Node fails the new connection there. The other choice is Node's behavior: delete the settle in connect() and kCanceledWrite.
• cirospaciari: one hook in _destroy, against a fix in each close handler (drafts tls: minDHSize validation, replaceable createSecureContext, ECANCELED on cancelled TLS writes (+5 tests) #35386 and node: net/tls/http/http2 compat fixes #41400). The request on node:net: queue what EAGAIN leaves of a write to an adopted fd, cancel it on destroy() #41835 is the contract of this PR: "Please settle it with ECANCELED on destroy like Node, and add a test for that case that passes on both Node and Bun." With this hook, _destroy has taken the write before a close handler looks for it. The tail of a close handler still serves a native close on a socket that is not destroyed.

destroy(), then connect(): what the rule covers. The test fixture under each runtime: a client has a 64 MB write in flight and one write queued, then the teardown runs, then the client calls connect() to the same server, which answers the new connection with again.

	Node v26.3.0	main (2d6d4454f3)	this PR
destroy(), then connect()	write ECANCELED write, queued ECANCELED write, error ECANCELED write. The new connection fails.	write ERR_SOCKET_CLOSED, queued ERR_SOCKET_CLOSED, end, close false, data again	write ECANCELED write, queued ECANCELED write, close false, data again
peer reset, then connect() in the 'error' listener	error ECONNRESET read, write ECANCELED write, queued ECANCELED write, error ECANCELED write. The new connection fails.	error ECONNRESET read, close true, data again. No write callback.	error ECONNRESET read, write ECANCELED write, queued ECONNRESET read, close true, data again

• The rule covers the connect request (usockets: tell a socket's holder it is gone exactly once, whoever closes it and whether or not it ever opened #44327) and the write in flight (this PR), nothing else. The 'close' in these rows is the one of the connection that was given up. The socket gets it after connect(), here as on main.
• Node's documentation of socket.connect(): "This function should only be used for reconnecting a socket after 'close' has been emitted or otherwise it may lead to undefined behavior."
• A write callback that throws inside that connect() does not stop the dial. The exception is thrown again on the next tick, as an uncaught exception. Main swallows it.

Why the cancel waits for the handle. Node completes the canceled write when the handle closes: behind 'error', behind the ticks and microtasks that the 'error' listeners and the caller of destroy() queued, and directly ahead of 'close'. The cancel here has its own setImmediate, queued before the one that emits 'close'.

• Completed inside destroy(), it reaches node:http ahead of 'error', and a request that destroy(err) ended emits 'finish'. Main does that: write ERR_SOCKET_CLOSED, finish, error EBOOM, close. Node and this PR: error EBOOM, write ECANCELED write, close.
• Completed on the next tick (the earlier revision), it runs before the promise reactions to 'error'. A client that awaits both (for await, events.once, stream/promises.pipeline beside a write promise) then saw write ECANCELED first. Node and this PR report read ECONNRESET first, in 6 of 6 probes (client and accepted socket).
• Node runs the cancel before a 0 ms timer that was set after destroy(). In Bun that timer can run first: the cancel waits with 'close', which is on a setImmediate on main too.
• A canceled callback that throws is an uncaught exception, and 'close' still follows, as in Node. On main that throw is lost.

A destroyed socket gets no EOF (the first commit, the guard of #43392, item 1 of #43381). The native close handler pushed EOF into a stream that destroy() had already destroyed, so a plain destroy() emitted 'end', then 'close'. Node emits 'close' only. The earlier revision queued the cancel ahead of that 'end' to hide it. With the guard there is one ordering rule. This changes every socket, not only one with a write in flight:

reader, after socket.destroy()	Node v26.3.0 and this PR	main
'end' and 'close' listeners	close false	end, close false
for await (const chunk of socket)	rejects with ERR_STREAM_PREMATURE_CLOSE	ends normally
stream/promises.finished(socket)	rejects with ERR_STREAM_PREMATURE_CLOSE	the same, after an end

What main changed under this PR (rebased onto 2d6d4454f3, 263 commits):

• tls: consolidate the open TLS fixes (both engines, node:tls, node:https, WebSocket, SQL) #44618 holds a TLS write that the kernel rejected (holdRejectedWrite) and fails it later with the error of that send. cancelHeldWrite leaves that write alone. Test: destroy() does not cancel a write that the TLS engine rejected (an injected EPIPE, debug builds).
• tls: consolidate the open TLS fixes (both engines, node:tls, node:https, WebSocket, SQL) #44618 also makes a TLS socket emit 'connect' when the socket that it wraps connects (onUpgradedConnect). The identity guard that an earlier revision added to the 'close' listener of a write made while connecting is gone: no flow needs it now.
• A write that waits for the TLS handle (a server-side new TLSSocket(socket) attaches its handle one tick later) is canceled too. Node's TLSWrap holds that write. Before, it got ERR_SOCKET_CLOSED after 'close'.
• A write that waits for 'connect' is not canceled: its 'close' listener fails it with ERR_SOCKET_CLOSED_BEFORE_CONNECTION, as in Node.

Not like Node after this PR. #43381 tracks each one.

• The holder does not read and the peer closes. Node fails the write with the errno of its own send (write ECONNRESET or write EPIPE), then emits that 'error'. usockets reports the errno through the close, as a read error, so Bun gives error ... read, then write ECANCELED write. I ran ten holder states (holders.js in node:net, node:tls: socket teardown events that still differ from Node (spurious 'end', ERR_SOCKET_CLOSED in place of the real error) #43381). Node fails the write itself in eight of them. On main no state calls the write callback. Item 3.
• An accepted socket with no 'error' listener, after the peer's FIN: main closes it without an error and gives the write callback the error of the close (EPIPE). This PR keeps that. Node throws write EPIPE. Items 2 and 3.
• A native close with no error on a socket that is not destroyed, for example a peer that closes during the TLS handshake: the close handler still fails the write with ERR_SOCKET_CLOSED. Node's test-tls-writewrap-leak.js covers that flow and does not pass, here as on main. Items 2 and 4, and the rest of node:net: keep 'end' off a destroyed socket and report the read error behind a write in flight #43392.
• A TLS write that is pending when the handshake fails: Node gives it write EBADF (a rejected certificate) or fails it first with write EPROTO. Bun gives write ECANCELED. Main gives ERR_SOCKET_CLOSED ahead of 'error', and node:https then emits 'finish'.
• The text of the cancel is Node's in the three states that I compared (established, before the handshake, server-side wrap): write ECANCELED, or write ECANCELED Canceled because of SSL destruction while the handshake is not done.
• Other holders of a write callback keep their own rules: the sockets that node:http's server hands out (req.socket, 'upgrade', 'connect'), node:http2 streams, and a Windows named pipe. This PR does not reach them.

Not in this PR. A request asked for three more rules for the same write. Each one holds against Node v26.3.0 on main. None is the bug class of this PR, so they are tracked and not folded in:

• Async context: the callback of a write that waited runs in the context that opened the socket. node:net: complete a write that waited for the socket in the async context of the write #46141 is open for it. It wraps the callback where _write parks it, so the cancel of this PR then runs in the context of the write too.
• A throw in that callback, or in a 'drain' listener under it, becomes the 'error' of the socket: node:net, node:tls: socket teardown events that still differ from Node (spurious 'end', ERR_SOCKET_CLOSED in place of the real error) #43381, item 6. It is the listener-throw class of node:net: route throws from 'data'/'connection' listeners to uncaughtException and keep the socket alive #35347 and net: route throws from socket lifecycle listeners to uncaughtException #29762.
• A flush that fails sets _hadError before it calls the write back, and node:http then emits no 'finish': node:net, node:tls: socket teardown events that still differ from Node (spurious 'end', ERR_SOCKET_CLOSED in place of the real error) #43381, item 7.

Tests. One fixture process per runtime and per file runs every case, from a beforeAll hook. The tests only compare. Linux x64, a debug build of 2d6d4454f3, Node v26.3.0. Only the built net.js differs between the rows:

net.ts from	net, bun (21)	net, Node (17)	TLS, bun (16)	TLS, Node (16)	rejected write
main	20 fail	17 pass	15 fail	16 pass	pass
this PR	21 pass	17 pass	16 pass	16 pass	pass

• net, under both runtimes, for a client socket and for an accepted socket: peer reset, destroy(), destroy(err), destroy(err) followed by a tick and a microtask, destroy(err, cb) with a cb that throws, destroy() with a corked batch in flight, resetAndDestroy(), destroy() with no write in flight. One node:http request destroyed with its body in flight.
• net, bun only: the two rows of the reconnect table, a reconnect with a write callback that throws, and the accepted socket with no 'error' listener. The last one passes on main by design.
• TLS, under both runtimes: four holders of an established connection (tls.connect({ port }), tls.connect({ socket }), a server-side new TLSSocket(socket), a socket of tls.Server) with destroy(), destroy(err) and a peer reset. Before the handshake: a server-side wrap with a write and destroy() in one tick, a wrapped client destroyed before its socket connects (passes on main by design), a peer reset during the handshake, and an https request to a server whose certificate is rejected.
• ws-client-compat-send.test.ts: the peer-reset case was skipped for npm ws, with the comment "node:net drops the callbacks of queued writes when the peer resets the connection". It now runs on Linux: 2 of 2 pass, and both fail with main's net.ts.
• No vendored test of Node's suite pins ECANCELED for a write in flight: no file in test/js/node/test/parallel names that code. Node's test-tls-writewrap-leak.js does, for a TLS write. It is not vendored, and it does not pass (see "Not like Node after this PR").

Each part of the change, removed alone from the built net.js:

removed	what fails
the EOF guard	10 net cases, 3 TLS cases
the deferral (cancel inside destroy())	10 net cases, 10 TLS cases
the close phase (cancel on the next tick)	8 net cases, 10 TLS cases
'close' behind the cancel on a socket with no handle	server: peer reset, 2 TLS cases
the settle in connect()	the bun fixture does not end, and its hook fails after 30 s
the try around that settle	the same
the kRejectedWrite guard	the rejected-write test
the 'connect' wait is not canceled	the wrapped client destroyed before its socket connects, and Node's test-net-write-cb-on-destroy-before-connect.js
the TLS-handle wait is canceled	the server-side wrap
the TLS text	2 TLS cases
the error of the quiet close	the accepted socket with no 'error' listener

Suites run on this tree (Linux x64, the debug build):

• node-net.test.ts (170 tests) and node-tls-connect.test.ts (388 tests), each also with main's net.js. A test that fails with this PR also fails with main's net.js, or it is a 5 s timeout. The first kind: unref should exit when no more work pending, should trigger error when aborted even if connection failed #13126, 4 tls.connect tests of peer certificates and ALPN, and should allow reconnecting after end() (5 passes in 6 runs with each net.js). The timeouts are in groups that start several debug processes at once. They change from run to run, they occur with main's net.js too, and each group passes when it runs alone.
• ws-client-compat-send.test.ts (90 pass), tls-syscall-fault.test.ts (48 pass), net-syscall-fault.test.ts (25 pass).
• Node's suite, as vendored: test-net-*, test-tls-*, test-http-* and test-https-* from parallel (775 files) and sequential (24 files). 795 pass. 4 fail, and fail the same way with main's net.js: test-http-agent-keepalive.js (1 pass in 13 runs, 3 in 13 with main's), test-http-client-timeout-option.js, test-https-timeout.js, and test-tls-client-allow-partial-trust-chain.js, which needs the test runner.
• tsc --noEmit -p src/js/tsconfig.json, oxlint on src/js and prettier report nothing.

Not run for this revision: Windows and macOS. This session has no machine for them. The peer-reset cases run on Linux only, the Node leg is off on Windows, and on Windows only tls.connect({ port }) with destroy() has a 64 MB write, as before. The new cases that need no kernel back-pressure run on every platform under bun.

Cost. Counted from the diff. A _destroy with no write in flight: cancelHeldWrite (1 call, 1 property read, 1 branch) and 1 branch on its result. A socket with no handle takes 1 more branch. connect(): 1 property read, 1 branch. An EOF (finishSocketEnd): 1 read of destroyed. A write that destroy() cancels: 3 property writes, 1 setImmediate and the error object. The debug bundle of node:net grows from 112,893 to 114,046 bytes. I did not build a release binary, and perf, valgrind, strace and bloaty are not in this container, so there is no instruction count.

Self-review of this revision. 32 concerns. 24 are addressed in the diff or in this text. Not taken:

• The two ERR_SOCKET_CLOSED tails of the close handlers (a native close on a socket that is not destroyed). That is the rest of node:net: keep 'end' off a destroyed socket and report the read error behind a write in flight #43392, which should land on top of this PR.
• The errno of a holder that does not read. It needs a change in what the close carries, or a classification in both close handlers. It is stated above and tracked.
• The peer-reset cases on macOS. Nothing here can measure which event arrives first on kqueue, so they stay on Linux.
• The Node leg on Windows for the cases that need no back-pressure. Not run, so not enabled.
• EBADF and EPROTO for a write that is pending when the handshake fails. That is the handshake path, tracked.
• Dropping the settle in connect() because nobody is known to reconnect in that window. It is what usockets: tell a socket's holder it is gone exactly once, whoever closes it and whether or not it ever opened #44327 decided for the connect request, and it is put to its author above.
• A test in Node's upstream format, and a write request record like ConnectReq in place of the three slots (kwriteCallback, kRejectedWrite, kCanceledWrite). Both are questions for a maintainer.

Earlier rounds raised 14 concerns, 13 addressed. The one that was not (a reconnect in the tick of destroy() failed the new connection) is addressed now.

Order with open PRs.

• node:net: keep 'end' off a destroyed socket and report the read error behind a write in flight #43392 is the other half: the read error with no 'error' listener, and the ERR_SOCKET_CLOSED tails. It should land on top of this PR. Its EOF guard is here, and its own cancel in the close handlers (cancelPendingWriteAfterClose, 5 calls) finds no write after this hook. Merged first, it fails the new connection of destroy() then connect() with ERR_SOCKET_CLOSED (measured on ea6a2c7b7c). net.ts of the two branches merges without a conflict.
• node:net: complete a write that waited for the socket in the async context of the write #46141: see "Not in this PR". It does not merge with main today. With this PR it has one more conflict hunk, in the branch of _destroy for a socket with no handle. The PR that lands second routes that setImmediate(emitCloseNT, ...) through scheduleClose of node:net: complete a write that waited for the socket in the async context of the write #46141.
• node:tls: complete write(cb) and end(cb) over a Duplex when the stream completes the ciphertext #43877 makes a TLS write park its callback until the transport has taken the ciphertext, in the same slot, and does not settle it on a peer reset. On 2026-09-25 I built the merge of both branches as they were then: over a net.Socket the write callback was never called in 50 of 50 runs without this PR, and the sequence was Node's in 50 of 50 with it. Not repeated: node:tls: complete write(cb) and end(cb) over a Duplex when the stream completes the ciphertext #43877 does not merge with main today. Land this PR before it or together with it.
• node:net: queue what EAGAIN leaves of a write to an adopted fd, cancel it on destroy() #41835 adds its own cancel in _destroy for the adopted-fd sink. The PR that lands second must keep one helper.
• node:net: hold queued _writev chunks by reference instead of concat + native copy #35940 keeps the chunks of an in-flight _writev batch in _pendingData. cancelHeldWrite reads a non-null _pendingData as a write that waits for 'connect', so that batch would not be canceled, and the corked-batch case fails. node:net: hold queued _writev chunks by reference instead of concat + native copy #35940 must mark that state another way.

Repro (plain bun file.js and node file.js, no fault injection):

const net = require("node:net");
const events = [];
const server = net.createServer(sock => {
  sock.on("error", () => {});
  sock.pause();
  setTimeout(() => sock.resetAndDestroy(), 300);
});
server.listen(0, "127.0.0.1", () => {
  const c = net.connect(server.address().port, "127.0.0.1", () => {
    const ok = c.write(Buffer.alloc(64 * 1024 * 1024, 0x41), err =>
      events.push(`write cb ${err ? err.code + " " + err.syscall : "ok"}`));
    events.push(`write returned ${ok}`);
  });
  c.on("error", e => events.push(`error ${e.code} ${e.syscall}`));
  c.on("close", () => {
    events.push("close");
    setTimeout(() => { console.log(JSON.stringify(events)); server.close(); }, 200);
  });
});

Event order, one write in flight and one queued behind it (Linux, the test fixture under each runtime):

teardown	main (2d6d4454f3)	Node v26.3.0 and this PR
peer reset (client or accepted socket)	error ECONNRESET read, close true. No write callback runs.	error ECONNRESET read, write ECANCELED write, queued ECONNRESET read, close true
destroy()	write ERR_SOCKET_CLOSED (inside destroy()), queued ERR_SOCKET_CLOSED, close false	write ECANCELED write, queued ECANCELED write, close false
destroy(err)	write ERR_SOCKET_CLOSED, queued EBOOM, error EBOOM, close true	error EBOOM, write ECANCELED write, queued EBOOM, close true
destroy(), nothing in flight	end, close false	close false

Why the chunk of the fixture is 64 MB. Under Node, a write is in flight when the first send is partial. libuv then sends a second time inside the same write(): uv_try_write, then uv__write from uv_write2. With 1 MB chunks the second send took the rest on macOS, and the write reported write ok (3 of 5 attempts on the darwin lanes of CI build 120615). On Linux the kernel takes 2.5 MB for a peer that never reads. With 64 MB chunks both darwin lanes passed on the first attempt (build 120621). On Windows the kernel takes the first two 64 MB writes whole, so the fixture writes until one write stays in flight.

Related PRs.

• net: invoke the pending write callback when a read error destroys the socket #33401 had the same goal on an older net.ts. The stale-PR cleanup closed it unmerged.
• tls: minDHSize validation, replaceable createSecureContext, ECANCELED on cancelled TLS writes (+5 tests) #35386 (draft) removes the same early return in SocketHandlers2.close. It gives ECANCELED to TLS sockets only and keeps ERR_SOCKET_CLOSED for plain TCP.
• node:net: fail the write when the flush at the end of the open dispatch gets a fatal send error #43026 covers the fatal send errno at the end of the open dispatch. The fixture writes outside that dispatch, so it does not depend on it.
• WebSocket: real closing handshake, one failure path, ws rewritten on native transports (consolidates the open WebSocket PRs) #45223 (merged) keeps the callbacks of queued writes in ws.ts because of this bug. That code stays. Its comment now says why it is still needed: Windows reports a write in flight as done after a peer reset (node:net, node:tls: socket teardown events that still differ from Node (spurious 'end', ERR_SOCKET_CLOSED in place of the real error) #43381, item 5).

---

no test proof · iteration 4 · platform-specific test(s) that do not run on this machine, deferring to CI, which covers all platforms: test/js/node/tls/node-tls-connect.test.ts, test/js/node/net/node-net.test.ts

[robobun]

Status: rebased onto main (2d6d4454f3) on 2026-10-21 and reworked after a self-review. The branch is two commits: 4e290a0640 (a destroyed socket gets no EOF) and 7958eadddc (the cancel). The PR waits for CI on 7958eadddc and for a maintainer review. Two points need a ruling. They are at the top of the PR body. #43381 tracks the differences from Node that this PR does not change.

How I reproduced it

1. Real kernel, no fault injection. The script is in the Notes of the PR body. A client writes 64 MB to a server that never reads, then the server calls resetAndDestroy().

   bun repro.js    # 1.4.3 canary (367d939d9), and a debug build of main (2d6d4454f3)
   ["write returned false","error ECONNRESET read","close"]
   
   node repro.js   # v26.3.0, and a debug build of this branch
   ["write returned false","error ECONNRESET read","write cb ECANCELED write","close"]
   

2. The new tests. Each file has one CommonJS fixture. One process per runtime runs every case: under bun and, on POSIX, under the system Node (24 or later), with one expected output for both.

   bun bd test test/js/node/net/node-net.test.ts -t "socket torn down with a write still in flight"
   bun bd test test/js/node/tls/node-tls-connect.test.ts -t "TLS socket torn down with a write still in flight"
   

   Linux x64, a debug build of 2d6d4454f3, Node v26.3.0. Only the built net.js differs between the rows:

   net.ts from	net, bun (21)	net, Node (17)	TLS, bun (16)	TLS, Node (16)
   main	20 fail	17 pass	15 fail	16 pass
   this branch	21 pass	17 pass	16 pass	16 pass

   I did not run Windows or macOS for this revision. The peer-reset cases run on Linux only, and the Node leg is off on Windows. The reasons are in the test comments and in node:net, node:tls: socket teardown events that still differ from Node (spurious 'end', ERR_SOCKET_CLOSED in place of the real error) #43381.

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Walkthrough

Socket destruction now cancels eligible in-flight writes. Socket and TLS tests verify cancellation errors, callback behavior, and event ordering during clean destruction, errored destruction, and peer resets.

Changes

Socket write cancellation

Layer / File(s)	Summary
Cancellation lifecycle src/js/node/net.ts	Eligible in-flight writes are detached before handle teardown and completed with UV_ECANCELED. Clean and errored destruction use different callback ordering. Connecting writes avoid duplicate callback completion.
Socket teardown validation test/js/node/net/node-net.test.ts	Tests cover peer resets, clean destruction, errored destruction, throwing destroy callbacks, corked writes, and client and server sockets.
TLS teardown validation test/harness.ts, test/js/node/tls/node-tls-connect.test.ts	The harness selects compatible Node runtimes. TLS tests verify canceled writes and close-event ordering for established and connecting sockets.

Suggested reviewers: cirospaciari

Priority: ➖ Normal

Merge Risk: ⚪ Minimal · up to 3dacc

The change cancels parked writes during socket teardown, and the supplied summaries describe net and TLS coverage for callback and event ordering. The prior callback-dispatch concern is not an established guideline violation, so no merge-blocking risk is identified.

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 and concisely describes the main change: canceling an in-flight write when the socket is destroyed.
Description check		The description explains the problem, fix, expected behavior, scope, tradeoffs, and verification results. It does not use the exact template headings, but it provides the required information in equiv…

Full details: Description check

Explanation

The description explains the problem, fix, expected behavior, scope, tradeoffs, and verification results. It does not use the exact template headings, but it provides the required information in equivalent sections.

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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.

[coderabbitai]

Actionable comments posted: 1

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• 🪄 Fix CodeRabbit comments on this PR

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Inline comments:
In `@src/js/node/net.ts`:
- Line 272: Update cancelWriteNT to invoke the user-supplied callback through
its intrinsic $call dispatch, passing undefined as this and the existing
cancellation error as the argument, rather than calling it directly.

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ℹ️ Review info

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Reviewing files that changed from the base of the PR and between 731bd47 and 46a274f.

📒 Files selected for processing (2)

• src/js/node/net.ts
• test/js/node/net/node-net.test.ts

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[claude]

I re-reviewed after the follow-up commit and found no bugs; the taken write is now settled from a finally, so a throwing destroy(err, cb) callback no longer loses it. Because this changes nextTick ordering inside Socket.prototype._destroy for every node:net/node:tls teardown, a human look is still worthwhile.

What was reviewed:

• takeInFlightWrite vs the three _write parking paths: connecting and pending-upgrade writes keep _pendingData set and are left to their 'close' listeners; only a write parked after $write returned 0 is taken.
• Cancel placement: 'close' is always emitted from setImmediate (closeSocketHandle, closeAdoptedTLSRawNowNT, terminate path), so the nextTick cancel lands before it in every branch; with err it follows the emitErrorCloseNT tick that onDestroy queues.
• Test matrix: the recorded-callback trick in the write loop relies on Writable deferring sync callbacks to nextTick, so only the in-flight write reports; base emits ERR_SOCKET_CLOSED/no callback, so each case fails without the fix.

Extended reasoning...

Overview

The PR changes Socket.prototype._destroy in /home/claude/bun/src/js/node/net.ts to take the write callback parked in kwriteCallback before the native handle closes and fail it on the next tick with ErrnoException(UV_ECANCELED, "write"), matching libuv's uv__stream_destroy. Three small named helpers are added (takeInFlightWrite, cancelWriteNT, finishDestroy). Tests are added alongside existing coverage in test/js/node/net/node-net.test.ts (client/server x reset/destroy()/destroy(err)/destroy(err, throwing cb)) and test/js/node/tls/node-tls-connect.test.ts (TLS destroy()).

Security risks

None identified. The change only affects the timing and error code of a write callback during teardown; no new parsing, no new network surface, and errors are routed through the existing ErrnoException machinery rather than hand-assigned .code.

Level of scrutiny

Moderate-to-high. _destroy is on every socket teardown path (plain TCP, TLS, wrapped duplex, resetAndDestroy, _closeAfterHandlingError), and the correctness argument rests on nextTick-vs-setImmediate ordering: the cancel must land after the 'error' tick that onDestroy queues and before the 'close' that closeSocketHandle/closeAdoptedTLSRawNowNT/the terminate branch emit from setImmediate. I traced each branch and the ordering holds, and the no-error case deliberately queues the cancel before the native close so state.errored is set before endReadableNT can emit 'end'. The remaining gap I noted in the prior run (a throw from a user Duplex's destroy() at the kupgraded teardown when err is set) is unchanged, but the base behaved the same or worse there, and it is already recorded inline.

Other factors

The second commit directly addressed the one inline finding from the earlier review by wrapping callback(err) in try/finally. I could not build a debug binary in this environment, so I did not execute the new tests; my confidence comes from reading _write, closeSocketHandle, and src/js/internal/streams/destroy.ts and confirming the asserted sequences follow from that code. The tests await 'close' rather than sleeping, reuse a single 1 MiB chunk, and gate the platform-dependent peer-reset case on Linux with a stated reason. Because this is a behavioral compat change on a hot path with several sibling teardown routes, a maintainer familiar with the net/TLS close ordering should still sign off.

[claude]

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

Beyond the inline nit, I re-checked the destroy(err, cb)-throws path raised on the previous push: finishDestroy now queues the cancel tick from a finally, and the new "cb that throws" case in node-net.test.ts pins the settled order. I also checked the _pendingData != null gate in takeInFlightWrite: the post-connect branch of _write nulls _pendingData before $write (net.ts:2847), so only writes that actually reached the handle are taken, and pre-connect / pre-upgrade writes stay with their existing 'close' listeners.

Extended reasoning...

This push addresses the only substantive finding from the prior review (a user destroy(err, cb) callback that throws previously exited _destroy before the error-path ECANCELED tick was queued). The fix routes callback(err) through finishDestroy, whose finally schedules cancelWriteNT, and a new test case asserts ["write ECANCELED write", "queued EBOOM", "close true"] for that scenario. The takeInFlightWrite gate relies on _pendingData being undefined/null only once a write has been handed to the native handle; _write sets it to null immediately before socket.$write and the pre-connect / pre-upgrade branches set it to the chunk, so the gate distinguishes the two states correctly. The remaining inline finding is a duplicated Node-version probe across two test files, which is a style nit. The change still alters event ordering during socket teardown for both node:net and node:tls, so a human maintainer's look at the ordering contract is worthwhile rather than an automated approve.

[robobun]

^{Updated 9:05 AM PT - Oct 21st, 2026}

❌ @robobun, your commit 7958ead has some failures in Build #130096 (All Failures)

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🧪   To try this PR locally:

bunx bun-pr 43250

That installs a local version of the PR into your bun-43250 executable, so you can run:

bun-43250 --bun

[claude]

I re-reviewed the latest push and found no bugs; the two points from earlier rounds (settling the taken write when a destroy(err, cb) callback throws, and sharing the Node-version probe) are addressed in the code by finishDestroy and runtimesWithNode. Because this changes the teardown ordering of every node:net/node:tls socket with a write in flight, a human look at the event-order contract is still worthwhile.

What was reviewed:

• takeInFlightWrite only takes a callback whose chunk already reached the native handle (_pendingData == null); writes parked on 'connect' or the TLS attach still settle through their own 'close' listener, and the new kwriteCallback !== callback guard in _write's connecting path prevents a double callback on wrapped sockets that never emit 'connect'.
• Tick ordering against internal/streams/destroy: with no error the cancel tick is queued before callback(err); with an error it is queued after the 'error' tick, and net's 'close' is emitted via setImmediate on every handle branch (plain, _closeAfterHandlingError, resetAndClosing, adopted TLS raw), so 'error' -> write cb -> 'close' holds.
• Native drain/error/close handlers that run after _destroy see a null kwriteCallback and become no-ops, so no path invokes the taken callback twice.
• Fixture correctness: the nth === writes check works because Writable defers user callbacks of synchronous writes to the next tick, so only the last (in-flight) write reports; a corked batch shares one callback and reports twice as expected.

Extended reasoning...

Overview

The PR changes Socket.prototype._destroy in src/js/node/net.ts to take the in-flight write callback (kwriteCallback) before any handle close, and to fail it on the next tick with ErrnoException(UV_ECANCELED, "write"), positioned before 'close' and after 'error' to match Node/libuv. A finishDestroy wrapper guarantees the error-path cancel tick is queued even when the user's destroy(err, cb) callback throws. The connecting-path onClose listener in _write gains an identity guard so a wrapped socket (which never emits 'connect' and so never removes that listener) does not fire the callback a second time. test/harness.ts gains nodeMajorVersion()/runtimesWithNode(), and the two test files add describe.each matrices run under Bun and Node >= 24.

Security risks

None identified. The change does not touch TLS verification, credentials, or parsing of untrusted input; it only alters when and with which error object an already-registered JS callback is invoked during socket teardown.

Level of scrutiny

High. Socket teardown ordering in node:net is contract that node:http, node:http2, node:tls, and userland pools depend on. I traced the two callback-invocation orders against src/js/internal/streams/destroy.ts (emitErrorCloseNT emits 'error' on a nextTick; the stream-level emitCloseNT is a no-op because Socket sets emitClose: false, and net's own 'close' is emitted via setImmediate in closeSocketHandle, closeAdoptedTLSRawNowNT, and the resetAndClosing branch, or via nextTick after finishDestroy in the no-handle branch). In all branches the cancel tick lands after 'error' and before 'close'. I also checked every other reader/writer of kwriteCallback (SocketHandlers.drain/error, SocketHandlers2.close/error, SocketEmitEndNT, finishSocketEnd, readStop, unrefAfterDrain, failWrite, onUpgradeWriteClose) and confirmed each either nulls-and-calls or is a no-op once the callback has been taken, so no double invocation path was found. The _pendingData != null gate is consistent with _write (nulls it at line 2847 once the chunk reaches the handle) and with both drain handlers (null it on either outcome).

I could not run the tests in this environment (no debug build, and test execution was not permitted), so the claim that the fixtures fail on the base and pass on this branch rests on reading the code rather than on execution. The Node reference lane requires Node >= 24; the system here has v22, so on such CI hosts only the Bun lane runs.

Other factors

Both prior inline findings from this reviewer were addressed by later commits (46a274f adds finishDestroy; 7aa6ccc adds the shared harness helper), and the CodeRabbit threads were resolved by a non-author. The PR description acknowledges a remaining gap (a throw from upgraded.destroy() or terminate() when an error is set still skips the cancel tick) which pre-exists on main and is out of scope. The tests await real observable events, drain pipes concurrently, use port: 0, and gate the Linux-only RST-ordering cases with skipIf(!isLinux). Given the breadth of downstream consumers of socket teardown ordering, a maintainer familiar with the http/tls suites should still confirm the behavior change is acceptable before merge.

[claude]

Code review found no issues

No high-confidence issues detected in this change.

[claude]

Code review found no issues

No high-confidence issues detected in this change.

[claude]

Code review found no issues

No high-confidence issues detected in this change.

[claude]

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

Beyond the inline finding, I also checked that the three settle sites for a canceled write (the immediate queued in _destroy, SocketEmitEndNT, and Socket.prototype.connect) each clear kCanceledWrite before invoking the callback, so a canceled write settles exactly once; and that the cancel immediate is now queued at the top of _destroy, before any user callback that could throw, so the earlier gap where a throwing destroy(err, cb) left the write unsettled no longer applies.

Extended reasoning...

The change touches src/js/node/net.ts (destroy/close ordering for an in-flight write, a new kCanceledWrite slot and three settle sites), a harness helper, and tests; it touches no auth, crypto or injection surface. Event-ordering in node:net is contract-sensitive and one verified finding is not being posted, so this stays a defer rather than an approve.

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

• 🟡 src/js/node/net.ts — nit: maintainers get a new symbol-keyed slot, kCanceledWrite, that is first written in cancelHeldWrite (src/js/node/net.ts:454) rather than declared in the Socket constructor like kwriteCallback at src/js/node/net.ts:2039. Fix: initialize this[kCanceledWrite] = undefined next to this[kwriteCallback] = undefined so every Socket has the slot from construction, keeping the shape stable across the destroy path.

  Why this was flagged

  The diff adds kCanceledWrite (src/js/node/net.ts:356) and assigns it only inside cancelHeldWrite at src/js/node/net.ts:454, read at src/js/node/net.ts:459 and src/js/node/net.ts:2327. The Socket constructor at src/js/node/net.ts:2039 declares the sibling slot kwriteCallback with a default but not the new one. Sockets that are destroyed with a write in flight therefore gain a property after construction and change object shape, while sockets that never do keep a different shape. No functional failure; this is the field-declaration convention the repository review guidance asks for in src/js/, and it does not apply to the base branch because the slot does not exist there.

  Verification: nit. Triggering condition: any Socket destroyed while a write is parked in kwriteCallback. The Socket constructor initializes the sibling slot this[kwriteCallback] = undefined; at net.ts:2039 but never kCanceledWrite, so sockets that go through the destroy-with-write-in-flight path add a property post-construction and diverge in shape from sockets that never do. Nothing functionally breaks.