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fix(http2): keep flow-controlled end-stream DATA alive until it is flushed (#1998) - #2007
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…ushed (#1998) > [!NOTE] > This PR was generated by an AI coding agent (Jetski) on behalf of @mosuem. ### Summary Fixes #1998: `sendData(bytes, endStream: true)` with more bytes than the peer's flow-control window stalled forever, because the stream was torn down before the flow-controlled remainder could be sent. Two things went wrong: 1. In `StreamMessageQueueOut.enqueueMessage`, `if (message.endStream) startClosing()` ran *before* `_messages.addLast(message)`. `startClosing()` synchronously calls `onCheckForClose()`, which saw an empty `_messages` and closed the queue while the `DataMessage` was still waiting for `WINDOW_UPDATE` credit. 2. In `StreamHandler._handleEndOfStreamRemote`, when the peer sent `END_STREAM` on a stream that was already `HalfClosedLocal` (the local side had called `sendData(..., endStream: true)`), the stream was removed from `_openStreams` immediately, even if `stream.outgoingQueue` still had `DATA` waiting on credit. Subsequent stream-level `WINDOW_UPDATE` frames from the peer were then ignored (RFC 9113 Section 6.9: a `WINDOW_UPDATE` on a closed stream is discarded), so the remaining data could never be sent. ### Changes - **`lib/src/flowcontrol/stream_queues.dart`**: Call `startClosing()` after `_messages.addLast(message)`, so `onCheckForClose()` only closes the queue once `_messages` has drained. - **`lib/src/streams/stream_handler.dart`**: In `_handleEndOfStreamRemote`, only remove the stream from `_openStreams` if `stream.outgoingQueue.wasClosed`; otherwise `_cleanupClosedStream` removes it once the outgoing queue has drained. ### Test Verification (Fails Before $\rightarrow$ Passes After) Added `send-data-exceeding-window-with-end-stream-completes` in `test/transport_test.dart` (server and client each send 100 000 bytes with `endStream: true` through a 65 535-byte window; the second case has the server respond with `END_STREAM` before the upload has drained). **Before fix:** ```text 00:05 +0 -1: transport-test flow-control send-data-exceeding-window-with-end-stream-completes [E] TimeoutException after 0:00:05.000000: Test timed out after 5 seconds. ``` **After fix:** ```text 00:00 +1: All tests passed! ```
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… mosum/http2-3-rst-noerror-and-end-stream-flow-control # Conflicts: # pkgs/http2/CHANGELOG.md
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Revisions updated by 19 package dependencies found. Moving forward revisions for: http. Commit message: [deps] rev http Revisions updated by `dart tools/rev_sdk_deps.dart http`. http (https://github.com/dart-lang/http/compare/c76dfb3..c76dfb3): c76dfb3 Wed Oct 28 10:21:55 2026 -0700 Brian Quinlan fix(http2): accept larger headers (dart-lang/http#2041) 23495b0 Mon Oct 26 15:17:28 2026 -0700 Brian Quinlan chore(cronet_http): ready 1.10.1 (dart-lang/http#2039) 27591d4 Mon Oct 26 15:08:10 2026 -0700 Brian Quinlan fix(cronet): avoid cronet namespace duplication (dart-lang/http#2034) 9cdb8da Fri Oct 23 11:14:21 2026 -0700 Kevin Moore Tighten pull_request_label workflow permissions (dart-lang/http#2035) 3998b87 Fri Oct 23 07:31:29 2026 +0200 Moritz fix(http2): do not head-of-line block HEADERS, RST_STREAM and GOAWAY behind window-exhausted DATA (dart-lang/http#2013) be2b51f Fri Oct 23 07:31:28 2026 +0200 Moritz fix(http2): Http2Client applies response-body backpressure to the HTTP/2 stream and uses 4 MiB / 16 MiB receive windows (dart-lang/http#2029) 3b504cf Thu Oct 22 06:28:12 2026 +0200 Moritz fix(http2): never write RST_STREAM ahead of the stream's still-queued HEADERS (dart-lang/http#2008) a641fac Thu Oct 22 06:28:12 2026 +0200 Moritz fix(http2): preserve the complete response on RST_STREAM(NO_ERROR) (dart-lang/http#2012) 5d896c7 Thu Oct 22 06:28:11 2026 +0200 Moritz fix(http2): keep flow-controlled end-stream DATA alive until it is flushed (`#1998`) (dart-lang/http#2007) c834aa0 Thu Oct 22 06:28:11 2026 +0200 Moritz fix(http2): ignore PRIORITY and unknown frames on streams and reject non-zero stream control frames (dart-lang/http#2006) 2d35515 Thu Oct 22 06:15:59 2026 +0200 Moritz fix(http2): replenish connection receive window when stream closes with unconsumed data (dart-lang/http#2005) 1217181 Tue Oct 20 19:17:59 2026 -0400 Mouad Debbar [http_multi_server] Prepare to release 3.2.3 (dart-lang/http#2028). http (https://github.com/dart-lang/http/compare/a8a24a0..c76dfb3): c76dfb3 Wed Oct 28 10:21:55 2026 -0700 Brian Quinlan fix(http2): accept larger headers (dart-lang/http#2041) 23495b0 Mon Oct 26 15:17:28 2026 -0700 Brian Quinlan chore(cronet_http): ready 1.10.1 (dart-lang/http#2039) 27591d4 Mon Oct 26 15:08:10 2026 -0700 Brian Quinlan fix(cronet): avoid cronet namespace duplication (dart-lang/http#2034) 9cdb8da Fri Oct 23 11:14:21 2026 -0700 Kevin Moore Tighten pull_request_label workflow permissions (dart-lang/http#2035) 3998b87 Fri Oct 23 07:31:29 2026 +0200 Moritz fix(http2): do not head-of-line block HEADERS, RST_STREAM and GOAWAY behind window-exhausted DATA (dart-lang/http#2013) be2b51f Fri Oct 23 07:31:28 2026 +0200 Moritz fix(http2): Http2Client applies response-body backpressure to the HTTP/2 stream and uses 4 MiB / 16 MiB receive windows (dart-lang/http#2029) 3b504cf Thu Oct 22 06:28:12 2026 +0200 Moritz fix(http2): never write RST_STREAM ahead of the stream's still-queued HEADERS (dart-lang/http#2008) a641fac Thu Oct 22 06:28:12 2026 +0200 Moritz fix(http2): preserve the complete response on RST_STREAM(NO_ERROR) (dart-lang/http#2012) 5d896c7 Thu Oct 22 06:28:11 2026 +0200 Moritz fix(http2): keep flow-controlled end-stream DATA alive until it is flushed () (dart-lang/http#2007) c834aa0 Thu Oct 22 06:28:11 2026 +0200 Moritz fix(http2): ignore PRIORITY and unknown frames on streams and reject non-zero stream control frames (dart-lang/http#2006) 2d35515 Thu Oct 22 06:15:59 2026 +0200 Moritz fix(http2): replenish connection receive window when stream closes with unconsumed data (dart-lang/http#2005) 1217181 Tue Oct 20 19:17:59 2026 -0400 Mouad Debbar [http_multi_server] Prepare to release 3.2.3 (dart-lang/http#2028) Change-Id: I259130f06771f4b7ba61c7610847e6677b5c8ed5 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/570641 Reviewed-by: Nate Bosch <[email protected]> Commit-Queue: Brian Quinlan <[email protected]>
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Note
This PR was generated by an AI coding agent (Jetski) on behalf of @mosuem.
Summary
Fixes #1998:
sendData(bytes, endStream: true)with more bytes than the peer's flow-control window stalled forever, because the stream was torn down before the flow-controlled remainder could be sent.Two things went wrong:
StreamMessageQueueOut.enqueueMessage,if (message.endStream) startClosing()ran before_messages.addLast(message).startClosing()synchronously callsonCheckForClose(), which saw an empty_messagesand closed the queue while theDataMessagewas still waiting forWINDOW_UPDATEcredit.StreamHandler._handleEndOfStreamRemote, when the peer sentEND_STREAMon a stream that was alreadyHalfClosedLocal(the local side had calledsendData(..., endStream: true)), the stream was removed from_openStreamsimmediately, even ifstream.outgoingQueuestill hadDATAwaiting on credit. Subsequent stream-levelWINDOW_UPDATEframes from the peer were then ignored (RFC 9113 Section 6.9: aWINDOW_UPDATEon a closed stream is discarded), so the remaining data could never be sent.Changes
lib/src/flowcontrol/stream_queues.dart: CallstartClosing()after_messages.addLast(message), soonCheckForClose()only closes the queue once_messageshas drained.lib/src/streams/stream_handler.dart: In_handleEndOfStreamRemote, only remove the stream from_openStreamsifstream.outgoingQueue.wasClosed; otherwise_cleanupClosedStreamremoves it once the outgoing queue has drained.Test Verification (Fails Before$\rightarrow$ Passes After)
Added
send-data-exceeding-window-with-end-stream-completesintest/transport_test.dart(server and client each send 100 000 bytes withendStream: truethrough a 65 535-byte window; the second case has the server respond withEND_STREAMbefore the upload has drained).Before fix:
After fix: