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node:http2: end the readable before the event of a HEADERS frame that carries END_STREAM - #42348
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… carries END_STREAM The native parser calls JS once per event: streamHeaders for a header block, then streamEnd when the frame carried END_STREAM. The nextTick queue drains between the two calls. The 'stream', 'response', 'push' and 'trailers' events fire inside the first call, so their listeners ran against a readable that had not seen the peer's END_STREAM yet. A listener that called close(code) with an error code had its stream destroyed before the readable got its EOF, and 'end' was never emitted although the peer's half was complete. close() used to hide this with an unconditional push(null), which #33607 gated. Node pushes null from onSessionHeaders before it emits the event, and from pushStream() for a server push, which has no inbound half. Do the same: endInboundHalf() runs ahead of the emit in both streamHeaders handlers and in pushStream(). The streamEnd handlers share the helper.
WalkthroughChangesThe HTTP/2 implementation adds shared inbound-half completion handling. Server and client paths now apply it to initial headers, subsequent headers, trailers, pushed streams, and close handling. Tests cover close codes, event ordering, timing, and runtime compatibility. HTTP/2 stream completion
Suggested reviewers: Priority: ⬇️ Low Merge Risk: ⚪ Minimal · up to The HTTP/2 EOF ordering change is covered across the affected server, client, trailer, and push-stream paths, with no remaining merge-blocking runtime risk. 🚥 Pre-merge checks | ✅ 4✅ Passed checks (4 passed)
Comment |
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Status: ready for review. How to reproduce the reported case:
// s1.cjs [sync|tick|immediate|timer] [code]
const http2 = require("http2");
const when = process.argv[2] || "sync", code = +(process.argv[3] || 2);
const ev = [];
const srv = http2.createServer();
srv.on("stream", st => {
for (const n of ["end", "aborted", "finish"]) st.on(n, () => ev.push("server " + n));
st.on("error", e => ev.push("server error " + e.code));
st.on("close", () => ev.push("server close rstCode=" + st.rstCode));
st.resume();
const go = () => { ev.push("close(" + code + ")"); st.close(code); };
if (when === "sync") go(); else if (when === "tick") process.nextTick(go);
else if (when === "immediate") setImmediate(go); else setTimeout(go, 50);
});
srv.listen(0, "127.0.0.1", () => {
const s = http2.connect("http://127.0.0.1:" + srv.address().port);
const r = s.request({ ":path": "/" });
r.on("error", () => {}); r.resume(); r.end();
setTimeout(() => { console.log(ev.join(" | ")); process.exit(0); }, 1000);
});
The other sites (server Self-reviewed: 4 concerns raised, 4 addressed. They were the sibling HEADERS frames that carry END_STREAM, the |
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Updated 11:43 AM PT - Sep 11th, 2026
✅ @robobun, your commit 9720a87a3a7d738d7e8333fe81788d7c1fcca103 passed in 🧪 To try this PR locally: bunx bun-pr 42348That installs a local version of the PR into your bun-42348 --bun |
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I reviewed this and found no bugs. Because it shifts the push(null) timing relative to user-visible 'stream'/'response'/'trailers'/'push' events across five re-entrant sites in node:http2, a human familiar with the module should still confirm the observable-state change is fully intended.
What was reviewed:
endInboundHalfplacement at all five HEADERS-dispatch sites andpushStream()— each is before the emit and gated onNGHTTP2_FLAG_END_STREAM, matching Node'sonSessionHeaders; the 1xx'headers'branch is correctly excluded.- Double-EOF: the later
streamEnddispatch still callsendInboundHalf, but it's gated onstream.readable, andReadable.push(null)is idempotent, so no duplicate'end'. - Test matrix: 56 cases wire
error/closeto settle the awaited promise, useport: 0, clean up infinally, and include the negative-contrast row (request open→ no'end'for error codes) so #33607's fix stays covered.
Extended reasoning...
Overview
This PR changes src/js/node/http2.ts to end the readable half of an Http2Stream synchronously when a HEADERS frame carrying END_STREAM is dispatched, before the corresponding 'stream'/'trailers'/'response'/'push' event fires, and does the same for the pushed stream in ServerHttp2Stream.pushStream(). A new endInboundHalf(stream) helper (sets rstCode = 0 if unset, then push(null)) replaces two inlined copies in the server/client streamEnd handlers and is invoked at four new sites in the two streamHeaders handlers plus pushStream. The test file gains a 56-case matrix (7 listener sites × 4 codes × sync/nextTick) asserting exact end/error:CODE/close:rstCode sequences, cross-runnable on Node.
Security risks
None. This is event-ordering in the node:http2 compat layer; no auth, crypto, parsing of untrusted lengths, or resource-limit changes. The test uses a local http2.createServer() on port: 0 with no external network contact.
Level of scrutiny
Medium-high. REVIEW.md and the Node/Web-compat guidance flag event ordering in node:* modules as load-bearing: "state mutations relative to event emission are observable because handlers re-enter." Moving push(null) before the emit changes what a 'stream'/'response' listener observes synchronously — not just whether 'end' eventually fires, but also stream.readable/readableEnded and the readable buffer's EOF marker at the moment the listener runs. The PR argues this is exactly Node's onSessionHeaders order and backs it with an 82-cell probe grid identical on Node v26.3.0, plus passing runs of test/js/node/http2/, Node's test-http2-*, grpc-js, and the fetch/serve HTTP/2 suites. That's strong evidence, but the surface area (five re-entrant emit sites, both session directions, push) is broad enough that a maintainer glance is worth the small cost.
Other factors
The change follows the review rules well: it fixes the whole bug class (client + server, initial headers + trailers + push), deduplicates within its own diff by extracting endInboundHalf, and the test matrix wires error/close to reject/resolve, cleans up in try/finally, uses port: 0, and includes the negative-contrast row so #33607's gate stays exercised. No CODEOWNERS entry covers these paths and there are no prior reviews or outstanding objections in the timeline. I checked that the later streamEnd handler's endInboundHalf call is guarded by stream.readable (and push(null) is idempotent on a Readable), so the earlier call doesn't produce a double EOF; and that the client 'headers' (1xx) branch is intentionally left out since a 1xx block cannot legitimately carry END_STREAM. The bug hunt exited on dry_streak with no findings.
…musl Alpine's node segfaults at a random point of this file under `node --test` (alpine 3.23 aarch64: build 114123 on main died in "while pending", build 114365 in "before response"). The bun half passes. The CI runner fails a file for any new core dump, whichever process wrote it, so the crash is not retried. The glibc, macOS and Windows lanes keep the cross-check.
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Inline comments:
In `@test/js/node/http2/node-http2-client-close.test.ts`:
- Around line 305-317: Replace the nested site and defer iteration in the
parameterized close tests with describe.each(), and replace the code/expected
iteration with test.each(). Preserve the existing site labels, timing
description, close codes, expected tables, and test behavior.
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src/js/node/http2.tstest/js/node/http2/node-http2-client-close.test.ts
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On the review's question, this is what a listener can observe now. All of it is intended: it is the order of node's
The review threads are answered and resolved. The function comment is one line now, and the |
3 participants
Problem
node:http2stream emits no'end'when a listener callsclose(code)with an error code (2, 7, 11) after the peer's half ended on a HEADERS frame: server'stream'and'trailers', client'response'and'trailers', thepushStream()callback. Node v26.3.0 and Bun 1.4.2 emit'end','error','close'. Main skips'end'.streamHeadershandlers (src/js/node/http2.ts) emit the event inside the HEADERS dispatch. The frame's END_STREAM reaches the readable only in the laterstreamEnddispatch, after the listener's ticks drain. By then the error has destroyed the stream and suppressed'end'. A pushed server stream never got an EOF.close()hid this with an unconditionalpush(null)until node:http2: fix ClientHttp2Stream.close(code) event sequence #33607 (fc479fb) gated it.Fix
endInboundHalf()gives the readable its EOF. BothstreamHeadershandlers call it before the event of a HEADERS frame that carries END_STREAM.pushStream()calls it for the new stream. Node'sonSessionHeadersandpushStreamdo the same.close()gate stays. With the peer's half still open, an error code gives no'end', as on Node.test/js/node/http2/node-http2-client-close.test.ts(56 new cases, 24 fail on main, all 68 pass on Node v26.3.0). Alsotest/js/node/http2/, Node'stest-http2-*, grpc-js,serve-http2, fetch HTTP/2.Background
streamHeadersfor a header block, thenstreamEndif the frame carried END_STREAM. ThenextTickqueue drains between the two.push(null)gives a Readable its EOF.'end'fires a tick later, unless the stream has an error by then.close(code)with a code other than NO_ERROR or CANCEL destroys the stream withERR_HTTP2_STREAM_ERROR.Notes
The regression is unreleased. A fuzz ledger found it, no user reported it.
"Before" below is
1.4.3-canary.1+4ff919377, the last build before #33607. The report measured the same sequences on 1.4.2.Server-side events for
close(2)inside the'stream'listener. The client sentrequest({':path':'/'}).end()with no body:Codes 7 and 11 behave like 2. Codes 0 and 8 agree on all four builds.
The other sites,
close(2)orclose(11)in the listener or one tick later. The column says whether'end'fires before'error':'stream', afterrespond({endStream: true})'trailers''response', response ended on HEADERS (204)'trailers'pushStream()callbackThree probe scripts cover these sites with codes 0, 8, 2, 11 (and 7 for the push), sync and nextTick. Their output on this branch is identical to Node v26.3.0 on all 82 cells.
Cells that #33607 moved to Node's sequence and that this PR keeps (
'end'forclose(2)on a server stream):end('hello')'stream''end''end''end'end('hello')'data', or a tick after it'end''end''end''end''end''end'END_STREAM on a DATA frame is not part of this change. nghttp2 ignores frames for a stream that
close()already reset, so Node emits no'end'in the'data'rows above, and main already agrees.Sites left out on purpose:
'headers'event (a 1xx block). A 1xx block with END_STREAM is malformed. Node reports it as'response'. Nothing changes there.streamPushhandler (PUSH_PROMISE). A PUSH_PROMISE cannot carry END_STREAM.The two shapes the report proposed, and why this PR uses neither:
'end'on server streams whose request is still open. Node does not emit it there. It also leaves the client'response'and'trailers'cells broken.close()runs. That is the defect.close()would have to ask the native layer, and any other code that looks at the readable inside the listener would still see the stale state.Related open PRs:
rstCode=0and no'error'in the no-body cells. It does not touch these hunks. With it,close()no longer sends END_STREAM first, so some'stream'cells would pass without this change. Theafter respond()cells stay red without it on both main and node:http2: send RST_STREAM when a server stream is reset #33380.rstCodea default of 0. If it lands, therstCodeguard inendInboundHalf()is dead and can go.endInboundHalf()also setsrstCode = 0when no reset set it, as thestreamEndhandlers did. Without that, a listener that resumes the stream inside'stream'readsrstCode === undefinedin its'end'handler, because'end'now fires before thestreamEnddispatch. Node reports 0.The Node cross-check inside the test file is now skipped on musl. Alpine's
nodesegfaults at a random point of this file undernode --test(alpine 3.23 aarch64, also on main in build 114123, before this change). The CI runner fails a file for any new core dump, whichever process wrote it. The glibc, macOS and Windows lanes keep the cross-check.Suites run on the debug build:
test/js/node/http2/(576 pass, 6 skip), 261test-http2-*and 18test-diagnostics-channel-http2-*Node tests,serve-http2,serve-http2-protocol,serve-http2-lifecycle,node-http2-ping-flood-staged,fetch-http2-client,fetch-http2-adversarial,fetch-http2-leak,undici-h2,wpt-h2,grpc-js, the http2 regression tests (25589, 24924, 26915, 29073).Local failures that also occur without the change: the
test-outlier-detection.test.tsejection tests (5 s timeouts on a loaded debug build, they flip between runs on main too),test tonic server, the grpc-js DNS tests (no network),http2-wrapper.test.ts(ECONNREFUSED, on the release build too), oneAsyncLocalStorage.test.tstiming test (debug build timeout).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/http2/node-http2-client-close.test.ts