changelog: specify checkambig=True to avoid ambiguity around truncation
authorFUJIWARA Katsunori <foozy@lares.dti.ne.jp>
Thu, 22 Sep 2016 21:51:59 +0900
changeset 30003 003c41edc5f5
parent 30002 14ad8e2a4abe
child 30004 557454ce854a
changelog: specify checkambig=True to avoid ambiguity around truncation 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 00changelog.i (and close transaction) 2. discard appended data by truncation (strip or rollback) 3. append same size but different data to 00changelog.i again Therefore, cache validation doesn't work after (3) as expected. To avoid such file stat ambiguity around truncation, this patch specifies checkambig=True for renaming or opening to write changes out at finalization. Even after this patch, avoiding file stat ambiguity of 00changelog.i around truncation isn't yet completed, because truncation side isn't aware of this issue. This is a part of ExactCacheValidationPlan. https://www.mercurial-scm.org/wiki/ExactCacheValidationPlan
mercurial/changelog.py
--- a/mercurial/changelog.py	Thu Sep 22 21:51:58 2016 +0900
+++ b/mercurial/changelog.py	Thu Sep 22 21:51:59 2016 +0900
@@ -382,9 +382,9 @@
             tmpname = self.indexfile + ".a"
             nfile = self.opener.open(tmpname)
             nfile.close()
-            self.opener.rename(tmpname, self.indexfile)
+            self.opener.rename(tmpname, self.indexfile, checkambig=True)
         elif self._delaybuf:
-            fp = self.opener(self.indexfile, 'a')
+            fp = self.opener(self.indexfile, 'a', checkambig=True)
             fp.write("".join(self._delaybuf))
             fp.close()
             self._delaybuf = None