#17616: Improve context manager tests, fix bugs in close method and mode docs.

'mode' docs fix: the file must always be opened in binary in Python3.

Bug in Wave_write.close: when the close method calls the check that the header
exists and it raises an error, the _file attribute never gets set to None, so
the next close tries to close the file again and we get an ignored traceback
in the __del__ method.  The fix is to set _file to None in a finally clause.
This represents a behavior change...in theory a program could be checking for
the error on close and then doing a recovery action on the still open file and
closing it again.  But this change will only go into 3.4, so I think that
behavior change is acceptable given that it would be pretty weird and unlikely
logic to begin with.
This commit is contained in:
R David Murray 2013-07-31 20:48:26 -04:00
parent abe639f115
commit 536ffe161c
3 changed files with 54 additions and 26 deletions

View File

@ -19,21 +19,20 @@ The :mod:`wave` module defines the following function and exception:
.. function:: open(file, mode=None)
If *file* is a string, open the file by that name, otherwise treat it as a
seekable file-like object. *mode* can be any of
seekable file-like object. *mode* can be:
``'r'``, ``'rb'``
``'rb'``
Read only mode.
``'w'``, ``'wb'``
``'wb'``
Write only mode.
Note that it does not allow read/write WAV files.
A *mode* of ``'r'`` or ``'rb'`` returns a :class:`Wave_read` object, while a
*mode* of ``'w'`` or ``'wb'`` returns a :class:`Wave_write` object. If
*mode* is omitted and a file-like object is passed as *file*, ``file.mode``
is used as the default value for *mode* (the ``'b'`` flag is still added if
necessary).
A *mode* of ``'rb'`` returns a :class:`Wave_read` object, while a *mode* of
``'wb'`` returns a :class:`Wave_write` object. If *mode* is omitted and a
file-like object is passed as *file*, ``file.mode`` is used as the default
value for *mode*.
If you pass in a file-like object, the wave object will not close it when its
:meth:`close` method is called; it is the caller's responsibility to close

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@ -69,22 +69,49 @@ class TestWave(unittest.TestCase):
self.assertEqual(params.comptype, self.f.getcomptype())
self.assertEqual(params.compname, self.f.getcompname())
def test_context_manager(self):
self.f = wave.open(TESTFN, 'wb')
self.f.setnchannels(nchannels)
self.f.setsampwidth(sampwidth)
self.f.setframerate(framerate)
self.f.close()
def test_wave_write_context_manager_calls_close(self):
# Close checks for a minimum header and will raise an error
# if it is not set, so this proves that close is called.
with self.assertRaises(wave.Error):
with wave.open(TESTFN, 'wb') as f:
pass
print('in test:', f._file)
with self.assertRaises(wave.Error):
with open(TESTFN, 'wb') as testfile:
with wave.open(testfile):
pass
def test_context_manager_with_open_file(self):
with open(TESTFN, 'wb') as testfile:
with wave.open(testfile) as f:
f.setnchannels(nchannels)
f.setsampwidth(sampwidth)
f.setframerate(framerate)
self.assertFalse(testfile.closed)
with open(TESTFN, 'rb') as testfile:
with wave.open(testfile) as f:
self.assertFalse(f.getfp().closed)
params = f.getparams()
self.assertEqual(params.nchannels, nchannels)
self.assertEqual(params.sampwidth, sampwidth)
self.assertEqual(params.framerate, framerate)
self.assertIsNone(f.getfp())
self.assertFalse(testfile.closed)
def test_context_manager_with_filename(self):
# If the file doesn't get closed, this test won't fail, but it will
# produce a resource leak warning.
with wave.open(TESTFN, 'wb') as f:
f.setnchannels(nchannels)
f.setsampwidth(sampwidth)
f.setframerate(framerate)
with wave.open(TESTFN) as f:
self.assertFalse(f.getfp().closed)
self.assertIs(f.getfp(), None)
with open(TESTFN, 'wb') as testfile:
with self.assertRaises(wave.Error):
with wave.open(testfile, 'wb'):
pass
self.assertEqual(testfile.closed, False)
params = f.getparams()
self.assertEqual(params.nchannels, nchannels)
self.assertEqual(params.sampwidth, sampwidth)
self.assertEqual(params.framerate, framerate)
self.assertIsNone(f.getfp())
if __name__ == '__main__':

View File

@ -448,11 +448,13 @@ class Wave_write:
def close(self):
if self._file:
self._ensure_header_written(0)
if self._datalength != self._datawritten:
self._patchheader()
self._file.flush()
self._file = None
try:
self._ensure_header_written(0)
if self._datalength != self._datawritten:
self._patchheader()
self._file.flush()
finally:
self._file = None
if self._i_opened_the_file:
self._i_opened_the_file.close()
self._i_opened_the_file = None