changelog: fix readpending if no pending data exist (issue4609) Since transaction are used for more than just changesets, it is possible to have a transaction without new changesets at all. In this case no ''00changelog.i.a' are written. In all cases the 'changelog.readpending' method is called if the repository has any pending data. The 'revlog' logic provides empty content if the file is missing, so the whole operation resulted in an empty changelog. We now skip reading the pending file if it is missing.

--- a/mercurial/changelog.py	Mon Apr 20 15:27:55 2015 +0200
+++ b/mercurial/changelog.py	Mon Apr 20 17:16:22 2015 +0200
@@ -267,6 +267,8 @@
         self.checkinlinesize(tr)
 
     def readpending(self, file):
+        if not self.opener.exists(file):
+            return # no pending data for changelog
         r = revlog.revlog(self.opener, file)
         self.index = r.index
         self.nodemap = r.nodemap