vfs: use checkambigatclosing in checkambig=True but atomictemp=False case
In Mercurial source tree, opening a file in "a"/"a+" mode like below
doesn't specify atomictemp=True for vfs, and this avoids file stat
ambiguity check by atomictempfile.
- writing changes out in revlog layer uses "a+" mode
- truncation in repair.strip() uses "a" mode
- truncation in transaction._playback() uses "a" mode
If steps below occurs at "the same time in sec", all of mtime, ctime
and size are same between (1) and (3).
1. append data to revlog-style file (and close transaction)
2. discard appended data by truncation (strip or rollback)
3. append same size but different data to revlog-style file again
Therefore, cache validation doesn't work after (3) as expected.
This patch uses checkambigatclosing in checkambig=True but
atomictemp=False case, to check (and get rid of) file stat ambiguity
at closing.
This is a part of ExactCacheValidationPlan.
https://www.mercurial-scm.org/wiki/ExactCacheValidationPlan
from __future__ import absolute_import, print_function
import os
from hgext import (
color,
)
from mercurial import (
dispatch,
ui as uimod,
)
# ensure errors aren't buffered
testui = color.colorui()
testui.pushbuffer()
testui.write(('buffered\n'))
testui.warn(('warning\n'))
testui.write_err('error\n')
print(repr(testui.popbuffer()))
# test dispatch.dispatch with the same ui object
hgrc = open(os.environ["HGRCPATH"], 'w')
hgrc.write('[extensions]\n')
hgrc.write('color=\n')
hgrc.close()
ui_ = uimod.ui()
ui_.setconfig('ui', 'formatted', 'True')
# we're not interested in the output, so write that to devnull
ui_.fout = open(os.devnull, 'w')
# call some arbitrary command just so we go through
# color's wrapped _runcommand twice.
def runcmd():
dispatch.dispatch(dispatch.request(['version', '-q'], ui_))
runcmd()
print("colored? " + str(issubclass(ui_.__class__, color.colorui)))
runcmd()
print("colored? " + str(issubclass(ui_.__class__, color.colorui)))