vfs: make rename avoid ambiguity of file stat if needed
In some cases below, renaming from backup is used to restore original
contents of a file. If renaming keeps ctime, mtime and size of a file,
restoring is overlooked, and old contents cached before restoring
isn't invalidated as expected.
- failure of transaction before closing (only from '.hg/journal.dirstate')
- rollback of previous transaction (from '.hg/undo.*')
- failure in dirstateguard scope (from '.hg/dirstate.SUFFIX')
To avoid such problem, this patch makes vfs.rename() avoid ambiguity
of file stat, if needed.
Ambiguity check is executed, only if:
- checkambig=True is specified (not all renaming needs ambiguity check), and
- destination file exists before renaming
This patch is a part of preparation for "Exact Cache Validation Plan":
https://www.mercurial-scm.org/wiki/ExactCacheValidationPlan
--- a/mercurial/scmutil.py Thu May 19 00:20:38 2016 +0900
+++ b/mercurial/scmutil.py Thu May 19 00:20:38 2016 +0900
@@ -377,8 +377,18 @@
def readlock(self, path):
return util.readlock(self.join(path))
- def rename(self, src, dst):
- return util.rename(self.join(src), self.join(dst))
+ def rename(self, src, dst, checkambig=False):
+ dstpath = self.join(dst)
+ oldstat = checkambig and util.filestat(dstpath)
+ if oldstat and oldstat.stat:
+ ret = util.rename(self.join(src), dstpath)
+ newstat = util.filestat(dstpath)
+ if newstat.isambig(oldstat):
+ # stat of renamed file is ambiguous to original one
+ advanced = (oldstat.stat.st_mtime + 1) & 0x7fffffff
+ os.utime(dstpath, (advanced, advanced))
+ return ret
+ return util.rename(self.join(src), dstpath)
def readlink(self, path):
return os.readlink(self.join(path))