Fix completed request cancellation cleanup - #2624
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CI note: I inspected the two failed Ubuntu jobs. They fail in existing tests that are not changed by this PR: Both pass locally on this branch: uv run --frozen --no-sync pytest tests/interaction/lowlevel/test_timeouts.py::test_session_level_timeout_applies_to_every_request -q
uv run --frozen --no-sync pytest tests/shared/test_streamable_http.py::test_client_crash_handled -qI do not have permission to rerun Actions on this repository, but these look like transient CI timing/port failures. Happy to patch if they reproduce consistently. |
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Docs-only. `AGENTS.md` is the first file every agent reads in this repo, and its account of `src/hive/_compat.py` had drifted from the code on three points. All three were verified against the source and against the upstream trackers before writing. ## 1. Wrong patch target AGENTS.md said the shim patches `RequestResponder.__exit__` to swallow an anyio `CancelledError`. It patches **`RequestResponder.respond`**, to short-circuit the upstream `assert not self._completed`. The `__exit__` patch was **removed** — `_compat.py`'s own docstring records why: the issue-#75 symptom stopped reproducing on `mcp >= 1.27`, because `Server._handle_request` catches the in-flight cancellation before it can reach `__exit__`. ## 2. Wrong upstream tracker, and a stale instruction AGENTS.md pointed at [python-sdk#2610](modelcontextprotocol/python-sdk#2610) with an escalation deadline of 2026-06-12 and an instruction to port the fix ourselves. The shim's fate is actually tied to [**#2416**](modelcontextprotocol/python-sdk#2416) — open, maintainer-bot-confirmed on both `main` and `origin/v1.x`, with a contributor volunteering to fix it on 2026-07-11 (and our own reproduction already posted there on 2026-06-19). Meanwhile #2610 already has an open upstream fix PR, [#2624](modelcontextprotocol/python-sdk#2624). Porting it ourselves would duplicate existing work. **This matters beyond the docs:** #127 is scoped as "if #2610 is still silent, port the fix as our own upstream PR". That premise no longer holds. #127 is commented separately rather than being silently rescoped here. ## 3. Stale pin, and a guard that no longer holds AGENTS.md quoted `mcp>=1.26,<2.0`, with the rationale that a narrow cap stops a major `RequestResponder` refactor from silently breaking the shim. The actual constraint is now `mcp>=1.27,<3.0` (widened by #316). `<3.0` admits `mcp` 2.x — precisely the major boundary the cap existed to exclude. I recorded this as a **lost guard** rather than silently re-narrowing the pin: `apply()` degrades loudly (logs a warning and no-ops) rather than silently, so this is not a live bug, and re-narrowing a dependency range is a decision with its own consequences, not a docs edit. Flagging it for a deliberate call. ## Verification No code changed, so no test impact. The three claims were checked against `src/hive/_compat.py` (docstring + `apply()`), `pyproject.toml:49`, and the three upstream trackers via the GitHub API.
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Rebased this fix onto v1.29.0 / |
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Summary
Fixes #2610.
CancelScope.__exit__only after aRequestResponderhas completed and sent its response.The implementation is rebased onto the maintained
v1.xline (v1.29.0), whereBaseSessionand this cleanup path remain active.Validation
pytest tests/shared/test_session.py tests/server/test_cancel_handling.py -q— 11 passedruff format --check src/mcp/shared/session.py tests/shared/test_session.pyruff check src/mcp/shared/session.py tests/shared/test_session.pypyright --pythonpath .venv/bin/python src/mcp/shared/session.py tests/shared/test_session.pygit diff --check