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
# extension to emulate invoking 'patch.internalpatch()' at the time
# specified by '[fakepatchtime] fakenow'
from __future__ import absolute_import
from mercurial import (
extensions,
patch as patchmod,
util,
)
def internalpatch(orig, ui, repo, patchobj, strip,
prefix='', files=None,
eolmode='strict', similarity=0):
if files is None:
files = set()
r = orig(ui, repo, patchobj, strip,
prefix=prefix, files=files,
eolmode=eolmode, similarity=similarity)
fakenow = ui.config('fakepatchtime', 'fakenow')
if fakenow:
# parsing 'fakenow' in YYYYmmddHHMM format makes comparison between
# 'fakenow' value and 'touch -t YYYYmmddHHMM' argument easy
fakenow = util.parsedate(fakenow, ['%Y%m%d%H%M'])[0]
for f in files:
repo.wvfs.utime(f, (fakenow, fakenow))
return r
def extsetup(ui):
extensions.wrapfunction(patchmod, 'internalpatch', internalpatch)