match: strengthen visit_children_set invariant, Recursive means "all files"
My previous interpretation of "Recursive" was too relaxed: I thought it
instructed the caller to do something like this:
> you can stop calling `visit_children_set` because you'll need to descend into
> every directory recursively, but you should still check every file if it
> matches or not
Whereas the real instruction seems to be:
> I guarantee that everything in this subtree matches, you can stop
> querying the matcher for all files and dirs altogether.
The evidence to support this:
- the test actually passes with the stronger invariant, revealing no
exceptions from this rule
- the implementation of `visit_children_set` for `DifferenceMatcher`
clearly relies on this requirement, so it must hold for that not to
lead to bugs.
import glob
import os
import shutil
import stat
import tempfile
import unittest
from mercurial import (
util,
)
atomictempfile = util.atomictempfile
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 range(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 range(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__)