intermediate changes

ref:614ed510ddd3cdf86a8c5dbf19afd113397e0172

1 files changed, 90 insertions, 0 deletions

diff --git a/contrib/python/pytest/py3/_pytest/threadexception.py b/contrib/python/pytest/py3/_pytest/threadexception.py
new file mode 100644
index 0000000000..1c1f62fdb7
--- /dev/null
+++ b/contrib/python/pytest/py3/_pytest/threadexception.py
@@ -0,0 +1,90 @@
+import threading
+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/threading_helper.py, with modifications.
+class catch_threading_exception:
+    """Context manager catching threading.Thread exception using
+    threading.excepthook.
+
+    Storing exc_value using a custom hook can create a reference cycle. The
+    reference cycle is broken explicitly when the context manager exits.
+
+    Storing thread using a custom hook can resurrect it if it is set to an
+    object which is being finalized. Exiting the context manager clears the
+    stored object.
+
+    Usage:
+        with threading_helper.catch_threading_exception() as cm:
+            # code spawning a thread which raises an exception
+            ...
+            # check the thread exception: use cm.args
+            ...
+        # cm.args attribute no longer exists at this point
+        # (to break a reference cycle)
+    """
+
+    def __init__(self) -> None:
+        # See https://github.com/python/typeshed/issues/4767 regarding the underscore.
+        self.args: Optional["threading._ExceptHookArgs"] = None
+        self._old_hook: Optional[Callable[["threading._ExceptHookArgs"], Any]] = None
+
+    def _hook(self, args: "threading._ExceptHookArgs") -> None:
+        self.args = args
+
+    def __enter__(self) -> "catch_threading_exception":
+        self._old_hook = threading.excepthook
+        threading.excepthook = 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
+        threading.excepthook = self._old_hook
+        self._old_hook = None
+        del self.args
+
+
+def thread_exception_runtest_hook() -> Generator[None, None, None]:
+    with catch_threading_exception() as cm:
+        yield
+        if cm.args:
+            if cm.args.thread is not None:
+                thread_name = cm.args.thread.name
+            else:
+                thread_name = "<unknown>"
+            msg = f"Exception in thread {thread_name}\n\n"
+            msg += "".join(
+                traceback.format_exception(
+                    cm.args.exc_type, cm.args.exc_value, cm.args.exc_traceback,
+                )
+            )
+            warnings.warn(pytest.PytestUnhandledThreadExceptionWarning(msg))
+
+
+@pytest.hookimpl(hookwrapper=True, trylast=True)
+def pytest_runtest_setup() -> Generator[None, None, None]:
+    yield from thread_exception_runtest_hook()
+
+
+@pytest.hookimpl(hookwrapper=True, tryfirst=True)
+def pytest_runtest_call() -> Generator[None, None, None]:
+    yield from thread_exception_runtest_hook()
+
+
+@pytest.hookimpl(hookwrapper=True, tryfirst=True)
+def pytest_runtest_teardown() -> Generator[None, None, None]:
+    yield from thread_exception_runtest_hook()