Mercurial > hg
view tests/test-atomictempfile.py @ 44998:f2de8f31cb59
pycompat: use os.fsencode() to re-encode sys.argv
Historically, the previous code made sense, as Py_EncodeLocale() and
fs.fsencode() could possibly use different encodings. However, this is not the
case anymore for Python 3.2, which uses the locale encoding as the filesystem
encoding (this is not true for later Python versions, but see below). See
https://vstinner.github.io/painful-history-python-filesystem-encoding.html for
a source and more background information.
Using os.fsencode() is safer, as the documentation for sys.argv says that it can
be used to get the original bytes. When doing further changes, the Python
developers will take care that this continues to work.
One concrete case where os.fsencode() is more correct is when enabling Python's
UTF-8 mode. Py_DecodeLocale() will use UTF-8 in this case. Our previous code
would have encoded it using the locale encoding (which might be different),
whereas os.fsencode() will encode it with UTF-8.
Since we don’t claim to support the UTF-8 mode, this is not really a bug and the
patch can go to the default branch. It might be a good idea to not commit this
to the stable branch, as it could in theory introduce regressions.
author | Manuel Jacob <me@manueljacob.de> |
---|---|
date | Wed, 24 Jun 2020 14:44:21 +0200 |
parents | 2372284d9457 |
children | 6000f5b25c9b |
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from __future__ import absolute_import import glob import os import shutil import stat import tempfile import unittest from mercurial import ( pycompat, util, ) atomictempfile = util.atomictempfile if pycompat.ispy3: xrange = range class testatomictempfile(unittest.TestCase): def setUp(self): self._testdir = tempfile.mkdtemp(b'atomictempfiletest') self._filename = os.path.join(self._testdir, b'testfilename') def tearDown(self): shutil.rmtree(self._testdir, True) def testsimple(self): file = atomictempfile(self._filename) self.assertFalse(os.path.isfile(self._filename)) tempfilename = file._tempname self.assertTrue( tempfilename in glob.glob(os.path.join(self._testdir, b'.testfilename-*')) ) file.write(b'argh\n') file.close() self.assertTrue(os.path.isfile(self._filename)) self.assertTrue( tempfilename not in glob.glob(os.path.join(self._testdir, b'.testfilename-*')) ) # discard() removes the temp file without making the write permanent def testdiscard(self): file = atomictempfile(self._filename) (dir, basename) = os.path.split(file._tempname) file.write(b'yo\n') file.discard() self.assertFalse(os.path.isfile(self._filename)) self.assertTrue(basename not in os.listdir(b'.')) # if a programmer screws up and passes bad args to atomictempfile, they # get a plain ordinary TypeError, not infinite recursion def testoops(self): with self.assertRaises(TypeError): atomictempfile() # checkambig=True avoids ambiguity of timestamp def testcheckambig(self): def atomicwrite(checkambig): f = atomictempfile(self._filename, checkambig=checkambig) f.write(b'FOO') f.close() # try some times, because reproduction of ambiguity depends on # "filesystem time" for i in xrange(5): atomicwrite(False) oldstat = os.stat(self._filename) if oldstat[stat.ST_CTIME] != oldstat[stat.ST_MTIME]: # subsequent changing never causes ambiguity continue repetition = 3 # repeat atomic write with checkambig=True, to examine # whether st_mtime is advanced multiple times as expected for j in xrange(repetition): atomicwrite(True) newstat = os.stat(self._filename) if oldstat[stat.ST_CTIME] != newstat[stat.ST_CTIME]: # timestamp ambiguity was naturally avoided while repetition continue # st_mtime should be advanced "repetition" times, because # all atomicwrite() occurred at same time (in sec) oldtime = (oldstat[stat.ST_MTIME] + repetition) & 0x7FFFFFFF self.assertTrue(newstat[stat.ST_MTIME] == oldtime) # no more examination is needed, if assumption above is true break else: # This platform seems too slow to examine anti-ambiguity # of file timestamp (or test happened to be executed at # bad timing). Exit silently in this case, because running # on other faster platforms can detect problems pass def testread(self): with open(self._filename, 'wb') as f: f.write(b'foobar\n') file = atomictempfile(self._filename, mode=b'rb') self.assertTrue(file.read(), b'foobar\n') file.discard() def testcontextmanagersuccess(self): """When the context closes, the file is closed""" with atomictempfile(b'foo') as f: self.assertFalse(os.path.isfile(b'foo')) f.write(b'argh\n') self.assertTrue(os.path.isfile(b'foo')) def testcontextmanagerfailure(self): """On exception, the file is discarded""" try: with atomictempfile(b'foo') as f: self.assertFalse(os.path.isfile(b'foo')) f.write(b'argh\n') raise ValueError except ValueError: pass self.assertFalse(os.path.isfile(b'foo')) if __name__ == '__main__': import silenttestrunner silenttestrunner.main(__name__)