Close #19266: contextlib.ignore -> contextlib.suppress

Patch by Zero Piraeus.
This commit is contained in:
Nick Coghlan 2013-10-17 23:40:57 +10:00
parent 1eb509a585
commit 240f86d7dd
6 changed files with 58 additions and 39 deletions

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@ -95,22 +95,27 @@ Functions and classes provided:
``page.close()`` will be called when the :keyword:`with` block is exited. ``page.close()`` will be called when the :keyword:`with` block is exited.
.. function:: ignore(*exceptions) .. function:: suppress(*exceptions)
Return a context manager that ignores the specified exceptions if they Return a context manager that suppresses any of the specified exceptions
occur in the body of a with-statement. if they occur in the body of a with statement and then resumes execution
with the first statement following the end of the with statement.
As with any other mechanism that completely suppresses exceptions, it As with any other mechanism that completely suppresses exceptions, this
should only be used to cover very specific errors where silently context manager should be used only to cover very specific errors where
ignoring the exception is known to be the right thing to do. silently continuing with program execution is known to be the right
thing to do.
For example:: For example::
from contextlib import ignore from contextlib import suppress
with ignore(FileNotFoundError): with suppress(FileNotFoundError):
os.remove('somefile.tmp') os.remove('somefile.tmp')
with suppress(FileNotFoundError):
os.remove('someotherfile.tmp')
This code is equivalent to:: This code is equivalent to::
try: try:
@ -118,6 +123,11 @@ Functions and classes provided:
except FileNotFoundError: except FileNotFoundError:
pass pass
try:
os.remove('someotherfile.tmp')
except FileNotFoundError:
pass
.. versionadded:: 3.4 .. versionadded:: 3.4

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@ -221,14 +221,17 @@ results should be less than 1% and may better match results found elsewhere.
contextlib contextlib
---------- ----------
The new :class:`contextlib.ignore` context manager helps to clarify the The new :class:`contextlib.suppress` context manager helps to clarify the
intent of code that deliberately ignores failures from a particular intent of code that deliberately suppresses exceptions from a single
operation. statement. (Contributed by Raymond Hettinger in :issue:`15806` and
Zero Piraeus in :issue:`19266`)
The new :class:`contextlib.redirect_stdio` context manager makes it easier The new :class:`contextlib.redirect_stdio` context manager makes it easier
for utility scripts to handle inflexible APIs that don't provide any for utility scripts to handle inflexible APIs that don't provide any
options to retrieve their output as a string or direct it to somewhere options to retrieve their output as a string or direct it to somewhere
other than :data:`sys.stdout`. other than :data:`sys.stdout`. (Contribute by Raymond Hettinger in
:issue:`15805`)
dis dis
@ -283,7 +286,7 @@ result: a bytes object containing the fully formatted message.
A pair of new subclasses of :class:`~email.message.Message` have been added, A pair of new subclasses of :class:`~email.message.Message` have been added,
along with a new sub-module, :mod:`~email.contentmanager`. All documentation along with a new sub-module, :mod:`~email.contentmanager`. All documentation
is currently in the new module, which is being added as part of the new is currently in the new module, which is being added as part of the new
:term:`provisional <provosional package>` email API. These classes provide a :term:`provisional <provisional package>` email API. These classes provide a
number of new methods that make extracting content from and inserting content number of new methods that make extracting content from and inserting content
into email messages much easier. See the :mod:`~email.contentmanager` into email messages much easier. See the :mod:`~email.contentmanager`
documentation for details. documentation for details.

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@ -5,7 +5,7 @@ from collections import deque
from functools import wraps from functools import wraps
__all__ = ["contextmanager", "closing", "ContextDecorator", "ExitStack", __all__ = ["contextmanager", "closing", "ContextDecorator", "ExitStack",
"ignore", "redirect_stdout"] "redirect_stdout", "suppress"]
class ContextDecorator(object): class ContextDecorator(object):
@ -179,10 +179,10 @@ class redirect_stdout:
sys.stdout = self.old_target sys.stdout = self.old_target
@contextmanager @contextmanager
def ignore(*exceptions): def suppress(*exceptions):
"""Context manager to ignore specified exceptions """Context manager to suppress specified exceptions
with ignore(OSError): with suppress(OSError):
os.remove(somefile) os.remove(somefile)
""" """

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@ -632,28 +632,6 @@ class TestExitStack(unittest.TestCase):
stack.push(cm) stack.push(cm)
self.assertIs(stack._exit_callbacks[-1], cm) self.assertIs(stack._exit_callbacks[-1], cm)
class TestIgnore(unittest.TestCase):
def test_no_exception(self):
with ignore(ValueError):
self.assertEqual(pow(2, 5), 32)
def test_exact_exception(self):
with ignore(TypeError):
len(5)
def test_multiple_exception_args(self):
with ignore(ZeroDivisionError, TypeError):
len(5)
def test_exception_hierarchy(self):
with ignore(LookupError):
'Hello'[50]
class TestRedirectStdout(unittest.TestCase): class TestRedirectStdout(unittest.TestCase):
def test_redirect_to_string_io(self): def test_redirect_to_string_io(self):
@ -663,5 +641,27 @@ class TestRedirectStdout(unittest.TestCase):
s = f.getvalue() s = f.getvalue()
self.assertIn('pow', s) self.assertIn('pow', s)
class TestSuppress(unittest.TestCase):
def test_no_exception(self):
with suppress(ValueError):
self.assertEqual(pow(2, 5), 32)
def test_exact_exception(self):
with suppress(TypeError):
len(5)
def test_multiple_exception_args(self):
with suppress(ZeroDivisionError, TypeError):
len(5)
def test_exception_hierarchy(self):
with suppress(LookupError):
'Hello'[50]
if __name__ == "__main__": if __name__ == "__main__":
unittest.main() unittest.main()

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@ -1003,6 +1003,7 @@ Anand B. Pillai
François Pinard François Pinard
Tom Pinckney Tom Pinckney
Zach Pincus Zach Pincus
Zero Piraeus
Michael Piotrowski Michael Piotrowski
Antoine Pitrou Antoine Pitrou
Jean-François Piéronne Jean-François Piéronne

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@ -42,6 +42,11 @@ Core and Builtins
Library Library
------- -------
- Issue #19266: Rename the new-in-3.4 ``contextlib.ignore`` context manager
to ``contextlib.suppress`` in order to be more consistent with existing
descriptions of that operation elsewhere in the language and standard
library documentation (Patch by Zero Piraeus)
- Issue #18891: Completed the new email package (provisional) API additions - Issue #18891: Completed the new email package (provisional) API additions
by adding new classes EmailMessage, MIMEPart, and ContentManager. by adding new classes EmailMessage, MIMEPart, and ContentManager.