Viewing file:  unraisableexception.py (3.12 KB) -rw-r--r--
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import sys
import traceback
import warnings
from types import TracebackType
from typing import Any
from typing import Callable
from typing import Generator
from typing import Optional
from typing import Type
import pytest
# Copied from cpython/Lib/test/support/__init__.py, with modifications.
class catch_unraisable_exception:
"""Context manager catching unraisable exception using sys.unraisablehook.
Storing the exception value (cm.unraisable.exc_value) creates a reference
cycle. The reference cycle is broken explicitly when the context manager
exits.
Storing the object (cm.unraisable.object) can resurrect it if it is set to
an object which is being finalized. Exiting the context manager clears the
stored object.
Usage:
with catch_unraisable_exception() as cm:
# code creating an "unraisable exception"
...
# check the unraisable exception: use cm.unraisable
...
# cm.unraisable attribute no longer exists at this point
# (to break a reference cycle)
"""
def __init__(self) -> None:
self.unraisable: Optional["sys.UnraisableHookArgs"] = None
self._old_hook: Optional[Callable[["sys.UnraisableHookArgs"], Any]] = None
def _hook(self, unraisable: "sys.UnraisableHookArgs") -> None:
# Storing unraisable.object can resurrect an object which is being
# finalized. Storing unraisable.exc_value creates a reference cycle.
self.unraisable = unraisable
def __enter__(self) -> "catch_unraisable_exception":
self._old_hook = sys.unraisablehook
sys.unraisablehook = self._hook
return self
def __exit__(
self,
exc_type: Optional[Type[BaseException]],
exc_val: Optional[BaseException],
exc_tb: Optional[TracebackType],
) -> None:
assert self._old_hook is not None
sys.unraisablehook = self._old_hook
self._old_hook = None
del self.unraisable
def unraisable_exception_runtest_hook() -> Generator[None, None, None]:
with catch_unraisable_exception() as cm:
yield
if cm.unraisable:
if cm.unraisable.err_msg is not None:
err_msg = cm.unraisable.err_msg
else:
err_msg = "Exception ignored in"
msg = f"{err_msg}: {cm.unraisable.object!r}\n\n"
msg += "".join(
traceback.format_exception(
cm.unraisable.exc_type,
cm.unraisable.exc_value,
cm.unraisable.exc_traceback,
)
)
warnings.warn(pytest.PytestUnraisableExceptionWarning(msg))
@pytest.hookimpl(hookwrapper=True, tryfirst=True)
def pytest_runtest_setup() -> Generator[None, None, None]:
yield from unraisable_exception_runtest_hook()
@pytest.hookimpl(hookwrapper=True, tryfirst=True)
def pytest_runtest_call() -> Generator[None, None, None]:
yield from unraisable_exception_runtest_hook()
@pytest.hookimpl(hookwrapper=True, tryfirst=True)
def pytest_runtest_teardown() -> Generator[None, None, None]:
yield from unraisable_exception_runtest_hook()
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