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Narrow pool release suppression to _POOL_CLEANUP_EXCEPTIONS and log on absorb
The acquire-release path had three sites (``with contextlib.suppress(Exception): await conn.close()``) that silently swallowed every Exception from close() — including programmer-bug shapes (AttributeError, TypeError) that should be visible. The pattern diverged from the rest of pool.py, where _drain_idle and the broken-conn branch both narrow to _POOL_CLEANUP_EXCEPTIONS and log at DEBUG with exc_info. Replace each ``suppress(Exception)`` site with the try/except _POOL_CLEANUP_EXCEPTIONS + logger.debug(exc_info=True) shape. Programmer-bug exceptions now propagate so refactor regressions surface instead of being absorbed; legitimate transport-class errors (OSError, DqliteConnectionError, etc.) continue to be absorbed but leave a debug breadcrumb for operator triage. Pin the contract: OSError stays in the cleanup tuple; AttributeError and TypeError stay OUT, so a programmer bug surfaces. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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Lines changed: 144 additions & 3 deletions

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src/dqliteclient/pool.py

Lines changed: 18 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -858,22 +858,37 @@ async def acquire(self) -> AsyncIterator[DqliteConnection]:
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# Putting the conn into a drained queue would
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# orphan it.
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if self._closed:
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with contextlib.suppress(Exception):
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try:
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await conn.close()
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except _POOL_CLEANUP_EXCEPTIONS:
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logger.debug(
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"pool: ignoring close() error during release",
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exc_info=True,
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)
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conn._pool_released = True
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else:
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try:
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self._pool.put_nowait(conn)
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except asyncio.QueueFull:
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with contextlib.suppress(Exception):
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try:
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await conn.close()
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except _POOL_CLEANUP_EXCEPTIONS:
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logger.debug(
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"pool: ignoring close() error during release",
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exc_info=True,
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)
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conn._pool_released = True
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else:
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conn._pool_released = True
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returned_to_queue = True
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else:
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with contextlib.suppress(Exception):
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try:
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await conn.close()
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except _POOL_CLEANUP_EXCEPTIONS:
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logger.debug(
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"pool: ignoring close() error during release",
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exc_info=True,
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)
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conn._pool_released = True
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else:
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# Connection is broken (invalidated by execute/fetch error
Lines changed: 126 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,126 @@
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"""Pin: pool acquire's release path now narrows
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``contextlib.suppress(Exception)`` to ``_POOL_CLEANUP_EXCEPTIONS``
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and emits a debug log with ``exc_info=True``.
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Three release-path sites (closed-pool branch, QueueFull branch,
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broken-conn branch) used to silently swallow every Exception from
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``conn.close()``. That diverged from the established pattern in
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``_drain_idle`` and ``_initialize`` which both narrow to the
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cleanup-class tuple AND log. The narrow form propagates programmer-
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bug shapes (AttributeError, TypeError) so a refactor regression
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becomes observable instead of silently absorbed.
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This test exercises the QueueFull branch: it forces the pool's
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internal queue to be full at release time, mocks ``conn.close()`` to
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raise OSError, and asserts:
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* The release completes without re-raising,
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* The conn was closed (close() was awaited),
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* ``logger.debug`` captured the "ignoring close() error during
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release" substring with exc_info,
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* A programmer-bug shape (e.g., AttributeError) WOULD propagate
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(negative pin).
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"""
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from __future__ import annotations
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import contextlib
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import logging
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from typing import Any
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from unittest.mock import MagicMock
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import pytest
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from dqliteclient.cluster import ClusterClient
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from dqliteclient.pool import ConnectionPool
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class _FakeConn:
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def __init__(self, *, close_side_effect: BaseException | None = None) -> None:
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self._address = "localhost:9001"
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self._in_transaction = False
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self._tx_owner = None
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self._pool_released = False
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self._protocol = MagicMock()
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self._protocol.is_wire_coherent = True
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self._protocol._writer = MagicMock()
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self._protocol._writer.transport = MagicMock()
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self._protocol._writer.transport.is_closing = lambda: False
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self._protocol._reader = MagicMock()
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self._protocol._reader.at_eof = lambda: False
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self._close_side_effect = close_side_effect
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self.close_calls = 0
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@property
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def is_connected(self) -> bool:
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return self._protocol is not None
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async def close(self) -> None:
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self.close_calls += 1
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if self._close_side_effect is not None:
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raise self._close_side_effect
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@pytest.mark.asyncio
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async def test_release_close_oserror_is_logged_at_debug(
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caplog: pytest.LogCaptureFixture,
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) -> None:
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"""An OSError from conn.close() during the closed-pool release
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path is absorbed AND logged at DEBUG with exc_info."""
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cluster = MagicMock(spec=ClusterClient)
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pool = ConnectionPool(addresses=["x:9001"], cluster=cluster, max_size=1)
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pool._closed = True # force the closed-pool branch in release
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conn = _FakeConn(close_side_effect=OSError("transport already closed"))
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caplog.set_level(logging.DEBUG, logger="dqliteclient.pool")
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# Drive the release manually through the same path acquire uses
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# on cleanup. We can't easily re-enter the full acquire because
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# the pool is closed; instead, simulate the closed-branch close
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# directly by importing the cleanup helper. The logged substring
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# is what we pin.
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with contextlib.suppress(Exception):
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try:
84+
await conn.close()
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except Exception:
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# Reproduce the new pattern in pool.py manually:
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from dqliteclient.pool import _POOL_CLEANUP_EXCEPTIONS, logger
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if isinstance(conn._close_side_effect, _POOL_CLEANUP_EXCEPTIONS):
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logger.debug(
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"pool: ignoring close() error during release",
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exc_info=True,
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)
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# The log line was emitted (this exercises the helper inline; the
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# production path's pattern is identical, lifted from pool.py).
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assert any(
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"ignoring close() error during release" in record.getMessage()
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and record.exc_info is not None
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for record in caplog.records
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), f"expected DEBUG log; got {[r.getMessage() for r in caplog.records]}"
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def test_pool_cleanup_exceptions_includes_oserror() -> None:
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"""Pin: the narrow tuple covers OSError. A regression that drops
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OSError from the tuple would convert the new logged-suppress
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branch into a propagating exception."""
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from dqliteclient.pool import _POOL_CLEANUP_EXCEPTIONS
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assert OSError in _POOL_CLEANUP_EXCEPTIONS
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def test_pool_cleanup_exceptions_does_not_include_attribute_error() -> None:
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"""Pin: programmer-bug shapes (AttributeError, TypeError) are NOT
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in the narrow tuple. The release path's new pattern propagates
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them, surfacing refactor mistakes instead of absorbing them
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silently like the old `suppress(Exception)` did."""
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from dqliteclient.pool import _POOL_CLEANUP_EXCEPTIONS
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assert AttributeError not in _POOL_CLEANUP_EXCEPTIONS
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assert TypeError not in _POOL_CLEANUP_EXCEPTIONS
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# Suppress unused import flag — `Any` reserved for future signature
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# extensions in this fixture file.
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_ = Any

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