tests/test-filecache.py

scmutil: handle conflicting files and dirs in origbackuppath

When ui.origbackuppath is set, .orig files are stored outside of the working
copy.  However conflicts can occur when files or directories end up having the
same name.  These conflicts cause Mercurial to abort, even if they've been
created as a result of different backups.

Make sure we always replace files or directories in the origbackuppath if
they conflict with another file or directory.

Test Plan:
Add new unit test for conflicting paths.

Differential Revision: https://phab.mercurial-scm.org/D680

from __future__ import absolute_import, print_function
import os
import subprocess
import sys

if subprocess.call(['python', '%s/hghave' % os.environ['TESTDIR'],
                    'cacheable']):
    sys.exit(80)

from mercurial import (
    extensions,
    hg,
    localrepo,
    ui as uimod,
    util,
    vfs as vfsmod,
)

class fakerepo(object):
    def __init__(self):
        self._filecache = {}

    class fakevfs(object):

        def join(self, p):
            return p

    vfs = fakevfs()

    def unfiltered(self):
        return self

    def sjoin(self, p):
        return p

    @localrepo.repofilecache('x', 'y')
    def cached(self):
        print('creating')
        return 'string from function'

    def invalidate(self):
        for k in self._filecache:
            try:
                delattr(self, k)
            except AttributeError:
                pass

def basic(repo):
    print("* neither file exists")
    # calls function
    repo.cached

    repo.invalidate()
    print("* neither file still exists")
    # uses cache
    repo.cached

    # create empty file
    f = open('x', 'w')
    f.close()
    repo.invalidate()
    print("* empty file x created")
    # should recreate the object
    repo.cached

    f = open('x', 'w')
    f.write('a')
    f.close()
    repo.invalidate()
    print("* file x changed size")
    # should recreate the object
    repo.cached

    repo.invalidate()
    print("* nothing changed with either file")
    # stats file again, reuses object
    repo.cached

    # atomic replace file, size doesn't change
    # hopefully st_mtime doesn't change as well so this doesn't use the cache
    # because of inode change
    f = vfsmod.vfs('.')('x', 'w', atomictemp=True)
    f.write('b')
    f.close()

    repo.invalidate()
    print("* file x changed inode")
    repo.cached

    # create empty file y
    f = open('y', 'w')
    f.close()
    repo.invalidate()
    print("* empty file y created")
    # should recreate the object
    repo.cached

    f = open('y', 'w')
    f.write('A')
    f.close()
    repo.invalidate()
    print("* file y changed size")
    # should recreate the object
    repo.cached

    f = vfsmod.vfs('.')('y', 'w', atomictemp=True)
    f.write('B')
    f.close()

    repo.invalidate()
    print("* file y changed inode")
    repo.cached

    f = vfsmod.vfs('.')('x', 'w', atomictemp=True)
    f.write('c')
    f.close()
    f = vfsmod.vfs('.')('y', 'w', atomictemp=True)
    f.write('C')
    f.close()

    repo.invalidate()
    print("* both files changed inode")
    repo.cached

def fakeuncacheable():
    def wrapcacheable(orig, *args, **kwargs):
        return False

    def wrapinit(orig, *args, **kwargs):
        pass

    originit = extensions.wrapfunction(util.cachestat, '__init__', wrapinit)
    origcacheable = extensions.wrapfunction(util.cachestat, 'cacheable',
                                            wrapcacheable)

    for fn in ['x', 'y']:
        try:
            os.remove(fn)
        except OSError:
            pass

    basic(fakerepo())

    util.cachestat.cacheable = origcacheable
    util.cachestat.__init__ = originit

def test_filecache_synced():
    # test old behavior that caused filecached properties to go out of sync
    os.system('hg init && echo a >> a && hg ci -qAm.')
    repo = hg.repository(uimod.ui.load())
    # first rollback clears the filecache, but changelog to stays in __dict__
    repo.rollback()
    repo.commit('.')
    # second rollback comes along and touches the changelog externally
    # (file is moved)
    repo.rollback()
    # but since changelog isn't under the filecache control anymore, we don't
    # see that it changed, and return the old changelog without reconstructing
    # it
    repo.commit('.')

def setbeforeget(repo):
    os.remove('x')
    os.remove('y')
    repo.cached = 'string set externally'
    repo.invalidate()
    print("* neither file exists")
    print(repo.cached)
    repo.invalidate()
    f = open('x', 'w')
    f.write('a')
    f.close()
    print("* file x created")
    print(repo.cached)

    repo.cached = 'string 2 set externally'
    repo.invalidate()
    print("* string set externally again")
    print(repo.cached)

    repo.invalidate()
    f = open('y', 'w')
    f.write('b')
    f.close()
    print("* file y created")
    print(repo.cached)

def antiambiguity():
    filename = 'ambigcheck'

    # try some times, because reproduction of ambiguity depends on
    # "filesystem time"
    for i in xrange(5):
        fp = open(filename, 'w')
        fp.write('FOO')
        fp.close()

        oldstat = os.stat(filename)
        if oldstat.st_ctime != oldstat.st_mtime:
            # subsequent changing never causes ambiguity
            continue

        repetition = 3

        # repeat changing via checkambigatclosing, to examine whether
        # st_mtime is advanced multiple times as expected
        for i in xrange(repetition):
            # explicit closing
            fp = vfsmod.checkambigatclosing(open(filename, 'a'))
            fp.write('FOO')
            fp.close()

            # implicit closing by "with" statement
            with vfsmod.checkambigatclosing(open(filename, 'a')) as fp:
                fp.write('BAR')

        newstat = os.stat(filename)
        if oldstat.st_ctime != newstat.st_ctime:
            # timestamp ambiguity was naturally avoided while repetition
            continue

        # st_mtime should be advanced "repetition * 2" times, because
        # all changes occurred at same time (in sec)
        expected = (oldstat.st_mtime + repetition * 2) & 0x7fffffff
        if newstat.st_mtime != expected:
            print("'newstat.st_mtime %s is not %s (as %s + %s * 2)" %
                  (newstat.st_mtime, expected, oldstat.st_mtime, repetition))

        # no more examination is needed regardless of result
        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

print('basic:')
print()
basic(fakerepo())
print()
print('fakeuncacheable:')
print()
fakeuncacheable()
test_filecache_synced()
print()
print('setbeforeget:')
print()
setbeforeget(fakerepo())
print()
print('antiambiguity:')
print()
antiambiguity()