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bpo-36829: Document test.support.catch_unraisable_exception() (GH-13554) · python/cpython@6dbbe74

3 files changed

lines changed

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@@ -1081,6 +1081,26 @@ The :mod:`test.support` module defines the following functions:

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:exc:`PermissionError` is raised.

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.. function:: catch_unraisable_exception()

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Context manager catching unraisable exception using

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:func:`sys.unraisablehook`.

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Usage::

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with support.catch_unraisable_exception() as cm:

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# code creating an "unraisable exception"

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...

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# check the unraisable exception: use cm.unraisable

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...

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# cm.unraisable attribute no longer exists at this point

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# (to break a reference cycle)

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.. versionadded:: 3.8

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.. function:: find_unused_port(family=socket.AF_INET, socktype=socket.SOCK_STREAM)

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Returns an unused port that should be suitable for binding. This is

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@@ -3043,12 +3043,14 @@ class catch_unraisable_exception:

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Usage:

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with support.catch_unraisable_exception() as cm:

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# code creating an "unraisable exception"

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...

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# check the expected unraisable exception: use cm.unraisable

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# check the unraisable exception: use cm.unraisable

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...

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# cm.unraisable is None here (to break a reference cycle)

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# cm.unraisable attribute no longer exists at this point

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# (to break a reference cycle)

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"""

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def __init__(self):

@@ -3065,5 +3067,5 @@ def __enter__(self):

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def __exit__(self, *exc_info):

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# Clear the unraisable exception to explicitly break a reference cycle

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self.unraisable = None

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del self.unraisable

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sys.unraisablehook = self._old_hook

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@@ -1098,18 +1098,14 @@ def test_error_through_destructor(self):

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# Test that the exception state is not modified by a destructor,

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# even if close() fails.

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rawio = self.CloseFailureIO()

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try:

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with support.catch_unraisable_exception() as cm:

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with self.assertRaises(AttributeError):

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self.tp(rawio).xyzzy

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with support.catch_unraisable_exception() as cm:

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with self.assertRaises(AttributeError):

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self.tp(rawio).xyzzy

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if not IOBASE_EMITS_UNRAISABLE:

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self.assertIsNone(cm.unraisable)

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elif cm.unraisable is not None:

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self.assertEqual(cm.unraisable.exc_type, OSError)

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finally:

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# Explicitly break reference cycle

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cm = None

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def test_repr(self):

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raw = self.MockRawIO()

@@ -2854,18 +2850,14 @@ def test_error_through_destructor(self):

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# Test that the exception state is not modified by a destructor,

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# even if close() fails.

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rawio = self.CloseFailureIO()

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try:

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with support.catch_unraisable_exception() as cm:

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with self.assertRaises(AttributeError):

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self.TextIOWrapper(rawio).xyzzy

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with support.catch_unraisable_exception() as cm:

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with self.assertRaises(AttributeError):

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self.TextIOWrapper(rawio).xyzzy

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if not IOBASE_EMITS_UNRAISABLE:

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self.assertIsNone(cm.unraisable)

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elif cm.unraisable is not None:

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self.assertEqual(cm.unraisable.exc_type, OSError)

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finally:

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# Explicitly break reference cycle

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cm = None

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# Systematic tests of the text I/O API

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