transaction: handle missing file in backupentries (instead of using entries)

The case where a backup of a missing file was requested was previously
handled by the 'entries' list. As the 'backupentries' is about to gain
ability to backup files outside of '.hg/store', we want it to be able
to handle the missing file too.

Reminder: using 'addbackup' on a missing file means that such file needs to be
deleted if we rollback the transaction.

mercurial/transaction.py

@@ -44,6 +44,7 def _playback(journal, report, opener, e
 
     backupfiles = []
     for f, b in backupentries:
+        if b:
         filepath = opener.join(f)
         backuppath = opener.join(b)
         try:
@@ -52,6 +53,12 def _playback(journal, report, opener, e
         except IOError:
             report(_("failed to recover %s\n") % f)
             raise
+        else:
+            try:
+                opener.unlink(f)
+            except (IOError, OSError), inst:
+                if inst.errno != errno.ENOENT:
+                    raise
 
     opener.unlink(journal)
     backuppath = "%s.backupfiles" % journal
@@ -85,6 +92,7 class transaction(object):
         self.entries = []
         self.map = {}
         # a list of ('path', 'backuppath') entries.
+        # if 'backuppath' is empty, no file existed at backup time
         self._backupentries = []
         self._backupmap = {}
         self.journal = journal
@@ -179,8 +187,7 class transaction(object):
             backuppath = self.opener.join(backupfile)
             util.copyfiles(filepath, backuppath, hardlink=hardlink)
         else:
-            self.add(file, 0)
-            return
+            backupfile = ''
 
         self._backupentries.append((file, backupfile))
         self._backupmap[file] = len(self._backupentries) - 1
@@ -331,6 +338,7 class transaction(object):
         if self.opener.isfile(self._backupjournal):
             self.opener.unlink(self._backupjournal)
             for _f, b in self._backupentries:
+                if b:
                 self.opener.unlink(b)
         self._backupentries = []
         self.journal = None