Report cancelled async fixture setup/teardown as fixture errors

changelog.d/1591.fixed.rst

@@ -0,0 +1,4 @@
+Fixed cancelled async fixture setup and teardown being propagated as
+``asyncio.CancelledError``, which could stop other fixtures from being torn down or break later
+tests that use the fixture. Also ensured ContextVars changed by async generator fixtures are
+restored when their teardown raises.

pytest_asyncio/plugin.py

@@ -382,6 +382,22 @@ def _sync_fixture_wrapper(
     return _sync_fixture_wrapper
 
 
+def _cancelled_fixture_error(
+    phase: Literal["setup", "teardown"],
+    request: FixtureRequest,
+) -> PytestAsyncioError:
+    """
+    Return the error to raise instead of a fixture's CancelledError.
+
+    CancelledError is a BaseException, so pytest does not handle it like other
+    fixture errors: it does not cache it as a setup error, and it does not run
+    a node's remaining finalizers after one is raised during teardown.
+    """
+    return PytestAsyncioError(
+        f"The {phase} of async fixture {request.fixturename!r} was cancelled."
+    )
+
+
 AsyncGenFixtureParams = ParamSpec("AsyncGenFixtureParams")
 AsyncGenFixtureYieldType = TypeVar("AsyncGenFixtureYieldType")
 
@@ -405,7 +421,10 @@ async def setup():
             return res
 
         context = contextvars.copy_context()
-        result = runner.run(setup(), context=context)
+        try:
+            result = runner.run(setup(), context=context)
+        except asyncio.CancelledError as e:
+            raise _cancelled_fixture_error("setup", request) from e
 
         reset_contextvars = _apply_contextvar_changes(context)
 
@@ -422,9 +441,13 @@ async def async_finalizer() -> None:
                     msg += "Yield only once."
                     raise ValueError(msg)
 
-            runner.run(async_finalizer(), context=context)
-            if reset_contextvars is not None:
-                reset_contextvars()
+            try:
+                runner.run(async_finalizer(), context=context)
+            except asyncio.CancelledError as e:
+                raise _cancelled_fixture_error("teardown", request) from e
+            finally:
+                if reset_contextvars is not None:
+                    reset_contextvars()
 
         request.addfinalizer(finalizer)
         return result
@@ -453,7 +476,10 @@ async def setup():
             return res
 
         context = contextvars.copy_context()
-        result = runner.run(setup(), context=context)
+        try:
+            result = runner.run(setup(), context=context)
+        except asyncio.CancelledError as e:
+            raise _cancelled_fixture_error("setup", request) from e
 
         # Copy the context vars modified by the setup task into the current
         # context, and (if needed) add a finalizer to reset them.

tests/async_fixtures/test_async_fixtures_contextvars.py

@@ -159,6 +159,27 @@ async def test(var_fixture_2):
     result.assert_outcomes(passed=1)
 
 
+def test_var_from_async_generator_reset_when_teardown_fails(pytester: Pytester):
+    pytester.makeini("[pytest]\nasyncio_default_fixture_loop_scope = function")
+    pytester.makepyfile(_prelude + dedent("""
+        @pytest_asyncio.fixture
+        async def var_fixture():
+            with context_var_manager("value"):
+                yield
+                raise RuntimeError("teardown failed")
+
+        @pytest.mark.asyncio
+        async def test(var_fixture):
+            assert _context_var.get() == "value"
+
+        def test_after_failed_teardown():
+            with pytest.raises(LookupError):
+                _context_var.get()
+        """))
+    result = pytester.runpytest("--asyncio-mode=strict")
+    result.assert_outcomes(passed=2, errors=1)
+
+
 def test_var_set_to_existing_value_ok(pytester: Pytester):
     pytester.makeini("[pytest]\nasyncio_default_fixture_loop_scope = function")
     pytester.makepyfile(_prelude + dedent("""

tests/async_fixtures/test_cancelled_fixtures.py

@@ -0,0 +1,92 @@
+"""Async fixtures whose setup or teardown is cancelled."""
+
+from __future__ import annotations
+
+from textwrap import dedent
+
+import pytest
+from pytest import Pytester
+
+
+def test_cancelled_teardown_does_not_prevent_teardown_of_other_fixtures(
+    pytester: Pytester,
+):
+    pytester.makeini("[pytest]\nasyncio_default_fixture_loop_scope = function")
+    pytester.makepyfile(dedent("""\
+        import asyncio
+
+        import pytest
+        import pytest_asyncio
+
+        torn_down = []
+
+        @pytest.fixture
+        def sync_fixture():
+            yield
+            torn_down.append("sync_fixture")
+
+        @pytest_asyncio.fixture
+        async def cancelled_teardown():
+            task = asyncio.create_task(asyncio.sleep(3600))
+            yield
+            task.cancel()
+            await task
+
+        @pytest.mark.asyncio
+        async def test_requests_fixtures(sync_fixture, cancelled_teardown):
+            pass
+
+        def test_other_fixture_was_torn_down():
+            assert torn_down == ["sync_fixture"]
+        """))
+    result = pytester.runpytest("--asyncio-mode=strict")
+    result.assert_outcomes(passed=2, errors=1)
+    result.stdout.fnmatch_lines(
+        [
+            "*ERROR at teardown of test_requests_fixtures*",
+            "E*CancelledError",
+            "The above exception was the direct cause of the following exception:",
+            "*PytestAsyncioError: The teardown of async fixture "
+            "'cancelled_teardown' was cancelled.",
+        ]
+    )
+
+
+@pytest.mark.parametrize("fixture_end", ("yield", "return"))
+def test_cancelled_setup_of_module_scoped_fixture_is_setup_error_of_each_test(
+    pytester: Pytester, fixture_end: str
+):
+    pytester.makeini("[pytest]\nasyncio_default_fixture_loop_scope = module")
+    pytester.makepyfile(dedent(f"""\
+        import asyncio
+
+        import pytest
+        import pytest_asyncio
+
+        @pytest_asyncio.fixture(scope="module")
+        async def cancelled_setup():
+            task = asyncio.create_task(asyncio.sleep(3600))
+            task.cancel()
+            await task
+            {fixture_end}
+
+        @pytest.mark.asyncio(loop_scope="module")
+        async def test_first(cancelled_setup):
+            pass
+
+        @pytest.mark.asyncio(loop_scope="module")
+        async def test_second(cancelled_setup):
+            pass
+        """))
+    result = pytester.runpytest("--asyncio-mode=strict")
+    result.assert_outcomes(errors=2)
+    result.stdout.fnmatch_lines(
+        [
+            "*ERROR at setup of test_first*",
+            "*PytestAsyncioError: The setup of async fixture "
+            "'cancelled_setup' was cancelled.",
+            "*ERROR at setup of test_second*",
+            "*PytestAsyncioError: The setup of async fixture "
+            "'cancelled_setup' was cancelled.",
+        ]
+    )