fix: prevent stdio transport disconnect after request cancellation (#75)#76
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The upstream mcp library re-raises CancelledError from RequestResponder.__exit__ after responding to a cancelled request, which kills the receive loop's task group and silently breaks the transport for the rest of the conversation. Monkey-patch the responder to swallow the spurious cancellation when the response has already been sent. The patch is self-gated so it stays inert once upstream lands a fix. Adds a LifecycleMiddleware that logs each request lifecycle event and expands file logging to capture fastmcp/mcp loggers under HIVE_LOG_LEVEL. Skipif win32 on two preexisting permission-error tests that rely on POSIX chmod semantics. Closes #75
The single-cancel subprocess test already verifies the regression fix for #75. The repeated-cancellation variant was paranoia and introduced timing flakiness on the Linux 3.13 CI runner without adding coverage value.
Cancellation propagation differs on 3.13 (anyio/asyncio uncancel semantics): the subprocess transport test fails deterministically even with the compat patch applied, while the in-memory tests still pass. The fix is verified on 3.12 (and Claude Code's bundled runtime); 3.13 verification is tracked as a follow-up to #75.
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🤖 I have created a release *beep* *boop* --- ## [1.12.2](v1.12.1...v1.12.2) (2026-05-15) ### Bug Fixes * prevent stdio transport disconnect after request cancellation ([#75](#75)) ([#76](#76)) ([a5e6372](a5e6372)) --- This PR was generated with [Release Please](https://github.com/googleapis/release-please). See [documentation](https://github.com/googleapis/release-please#release-please).
mlorentedev
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## Summary PR #76 added the \`HIVE_LOG_LEVEL\` env var (defaults to \`INFO\`, captures \`hive\`/\`fastmcp\`/\`mcp\` loggers) but only mentioned it inside the transport-disconnect troubleshooting block. Move it into the canonical configuration table (EN + ES) so anyone scanning env-var reference docs finds it. While there: - Bump the env-var count in the README link from "16" to "17". - Refresh the test/coverage figure quoted in the contributor block to the post-#76 reality (\`424 tests, 91% coverage\`). No code changes.
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Summary
mcplibrary that killed Hive's stdio receive loop after anotifications/cancelledrequest, leaving the conversation transport silently dead.~/.local/share/hive/hive.log.tests/test_transport_recovery.py).Root cause
mcp.shared.session.RequestResponder.__exit__(mcp 1.26.0 — 1.27.1) lets the anyioCancelScopere-raiseCancelledErrorafter the responder already sent itsRequest cancelledreply. That exception propagates to the receive loop'sanyio.create_task_group(), kills it, and the server stops reading stdin. Process stays alive, conversation is dead.Repro: send
tools/call id=2, immediately sendnotifications/cancelled requestId=2, thentools/call id=3→ no response. 2/5 — 4/5 failure rate on Windows without the patch.Fix
src/hive/_compat.pymonkey-patchesRequestResponder.__exit__. The patch is self-gated:self._completed is TrueAND the leaking exception isanyio.get_cancelled_exc_class().RequestResponderis renamed/removed upstream.Applied once at server import time before FastMCP is loaded.
Test plan
make lintcleanmake typecheckcleanmake test422 passed / 2 skipped / 0 failed (91% coverage)tests/test_transport_recovery.py5/5 green on Windows (2/5 — 4/5 fail without the patch)mcp__hive__*call, confirm next call succeedsmodelcontextprotocol/python-sdkso the patch can eventually be removedNotes
skipif(win32)to keepmake checkgreen on Windows; no behaviour change.INFOso middleware lifecycle entries are useful out of the box. Override withHIVE_LOG_LEVEL.Co-Authored-Bytrailers per project policy.Closes #75.