Release HTTP/2 semaphore permit on NoAvailableStreamIDError#1012
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Kludex merged 1 commit intoJun 2, 2026
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`handle_async_request` / `handle_request` acquires a permit from `_max_streams_semaphore` before calling `_h2_state.get_next_available_stream_id()`. If the stream-ID space is exhausted and `NoAvailableStreamIDError` is raised, the exception handler sets `_used_all_stream_ids` and decrements `_request_count` but never releases the permit — leaking it permanently. In practice `_used_all_stream_ids = True` prevents further requests on the connection, so the visible impact is limited, but the resource cleanup is still wrong. Add the missing `release()` call in both async and sync paths. Ports encode/httpcore#1061 (bysiber), via codeberg.org/httpxyz/httpcorexyz@e88f30b (first of two fixes bundled in that commit; the second lands in a separate PR). Co-Authored-By: Kadir Can Ozden <101993364+bysiber@users.noreply.github.com>
Merging this PR will not alter performance
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…om fork's e88f30b)
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Summary
AsyncHTTP2Connection.handle_async_requestacquires a permit from_max_streams_semaphorebefore callingself._h2_state.get_next_available_stream_id(). If the stream-ID space is exhausted andNoAvailableStreamIDErroris raised, the exception handler sets_used_all_stream_ids = Trueand decrements_request_countbut never releases the permit — leaking it permanently.In practice
_used_all_stream_ids = Trueprevents further requests on the same connection so the visible impact is limited, but the resource cleanup is still wrong.This PR adds the missing
release()call in both the async and sync paths.Ports encode/httpcore#1061 (bysiber, currently open upstream), via codeberg.org/httpxyz/httpcorexyz@e88f30b. The fork bundled this fix with encode/httpcore#1062; I'm splitting them into two httpx2 PRs to mirror the upstream split.
Notes
_async/http2.pywas edited by hand;_sync/http2.pywas regenerated byscripts/unasync.py.NoAvailableStreamIDErrorbranch is already marked# pragma: no coverbecause exhausting the H/2 client stream-ID space (≈ 2³⁰ requests) is impractical to exercise in a unit test. The upstream PR doesn't ship a test either. 100% coverage preserved.Note: this change was prepared with AI assistance (Claude Code).