marmoute created this revision. Herald added a reviewer: hg-reviewers. Herald added a subscriber: mercurial-patches.
REVISION SUMMARY This is a bits that is not really correct but works "fine" in practice. Lets write it down so that people stop wondering how that logic might be correct. It is not. REPOSITORY rHG Mercurial BRANCH default REVISION DETAIL https://phab.mercurial-scm.org/D11781 AFFECTED FILES mercurial/merge.py CHANGE DETAILS diff --git a/mercurial/merge.py b/mercurial/merge.py --- a/mercurial/merge.py +++ b/mercurial/merge.py @@ -1404,6 +1404,31 @@ atomictemp=atomictemp, ) if wantfiledata: + # XXX note that there is a race windows between the time we + # write the clean data into the file and we stats it. So a + # writting process meddling with the file content right as we + # writes it could cause bad data to be gathered. + # + # They are 2 data we gather here + # - the mode: + # That we actually just wrote, we should not need to read + # it from disk, (except not all mode might have survived + # the disk round-trip, which is another issue) + # - the mtime, + # That could be accurate enough on filesystem with + # nanosecond precision, but is read in a racy way. + # + # (note: we get the size from the data we write, which is sane) + # + # So in theory the data returned here are fully racy, but in + # practice "it works mostly fine". + # + # Do not be surprised if you end up reading this while + # looking for the source of some buggy status. Feel free to + # improve this in the future, but we cannot simply stop + # gathering information otherwise `hg status` call made after a + # large `hg update` runs would have to redo a similar amount of + # work to restore and compare all files content. s = wfctx.lstat() mode = s.st_mode mtime = timestamp.mtime_of(s) To: marmoute, #hg-reviewers Cc: mercurial-patches, mercurial-devel _______________________________________________ Mercurial-devel mailing list Mercurial-devel@mercurial-scm.org https://www.mercurial-scm.org/mailman/listinfo/mercurial-devel
