annotate tests/test-atomictempfile.py @ 39286:3c4b2e880273

log: respect graphshorten on terminal nodes (collapsing o-~ to just o~)

Internally we have a custom template that's inspired by ones that we have seen
in the community. Normally, this looks something like:

    o  0834ec17 spectral tip
    |  crecord: support x to toggle single, X to toggle a range
    o  ee932990 spectral @
    |  filemerge: allow specifying $hgeditor as merge-tools.X.executable
    @  66f04611 matt_harbison
    |  cext: fix truncation warnings in revlog on Windows
    o  42cc76d0 matt_harbison
    |  cext: fix revlog compiler error on Windows
    ~
    o  bd63ada7 stable boris
    |  phases: drop dead code in `newheads`
    ~

With graphshorten on, and the descriptions of the public nodes hidden, it looks
like this, note that the commits right before the ~ are still "full height":

    o  0834ec17 spectral tip
    |  crecord: support x to toggle single, X to toggle a range
    o  ee932990 spectral @
    |  filemerge: allow specifying $hgeditor as merge-tools.X.executable
    @  66f04611 matt_harbison
    o  42cc76d0 matt_harbison
    |
    ~
    o  bd63ada7 stable boris
    |
    ~

This patch makes them look like this, removing the | but keeping the ~:

    o  0834ec17 spectral tip
    |  crecord: support x to toggle single, X to toggle a range
    o  ee932990 spectral @
    |  filemerge: allow specifying $hgeditor as merge-tools.X.executable
    @  66f04611 matt_harbison
    o  42cc76d0 matt_harbison
    ~
    o  bd63ada7 stable boris
    ~

This originally removed the ~s entirely, but this was determined to be too much
information loss and potentially confusing. This would have looked like the
following (note that the last commit is on a different branch than all of the
ones above it, and they are *not* linearly related):

    o  0834ec17 spectral tip
    |  crecord: support x to toggle single, X to toggle a range
    o  ee932990 spectral @
    |  filemerge: allow specifying $hgeditor as merge-tools.X.executable
    @  66f04611 matt_harbison
    o  42cc76d0 matt_harbison
    o  bd63ada7 stable boris

Differential Revision: https://phab.mercurial-scm.org/D4363

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__)