fix(http2): cancel pipe_task and send RST_STREAM on response future drop#4042
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seanmonstar merged 2 commits intoMar 31, 2026
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When the client drops the response future (e.g. due to a timeout), send_task detects the cancellation but does not notify pipe_task. The pipe_task continues to hold the h2 SendStream, preventing a RST_STREAM from being sent and keeping flow-control window capacity locked. Add a oneshot channel between send_task and pipe_task. When send_task detects cancellation via poll_canceled, it signals pipe_task through the channel. pipe_task then calls send_reset(CANCEL) on the h2 SendStream, which sends RST_STREAM to the server and frees flow-control capacity. Closes hyperium#4040
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Co-authored-by: Sean McArthur <sean@seanmonstar.com>
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Great work tracking this down, thank you!
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When the client drops the response future (e.g. due to a timeout), send_task detects the cancellation but does not notify pipe_task. The pipe_task continues to hold the h2 SendStream, preventing a RST_STREAM from being sent and keeping flow-control window capacity locked.
Add a oneshot channel between send_task and pipe_task. When send_task detects cancellation via poll_canceled, it signals pipe_task through the channel. pipe_task then calls send_reset(CANCEL) on the h2 SendStream, which sends RST_STREAM to the server and frees flow-control capacity.
Closes #4040