transaction: always remove empty journal on abort

When transactions without entries were aborted, the journal (of size 0) was not
unlinked, which prevents subsequent operations until hg recover is run on the
repository.

We also make sure the journal is unlinked when committing, even if the provided
hook doesn't do so.

mercurial/transaction.py

@@ -1,165 +1,167 b''
 # transaction.py - simple journalling scheme for mercurial
 #
 # This transaction scheme is intended to gracefully handle program
 # errors and interruptions. More serious failures like system crashes
 # can be recovered with an fsck-like tool. As the whole repository is
 # effectively log-structured, this should amount to simply truncating
 # anything that isn't referenced in the changelog.
 #
 # Copyright 2005, 2006 Matt Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2, incorporated herein by reference.
 
 from i18n import _
 import os, errno
 import error
 
 def active(func):
     def _active(self, *args, **kwds):
         if self.count == 0:
             raise error.Abort(_(
                 'cannot use transaction when it is already committed/aborted'))
         return func(self, *args, **kwds)
     return _active
 
 def _playback(journal, report, opener, entries, unlink=True):
     for f, o, ignore in entries:
         if o or not unlink:
             try:
                 opener(f, 'a').truncate(o)
             except IOError:
                 report(_("failed to truncate %s\n") % f)
                 raise
         else:
             try:
                 fn = opener(f).name
                 os.unlink(fn)
             except (IOError, OSError), inst:
                 if inst.errno != errno.ENOENT:
                     raise
     os.unlink(journal)
 
 class transaction(object):
     def __init__(self, report, opener, journal, after=None, createmode=None):
         self.journal = None
 
         self.count = 1
         self.report = report
         self.opener = opener
         self.after = after
         self.entries = []
         self.map = {}
         self.journal = journal
         self._queue = []
 
         self.file = open(self.journal, "w")
         if createmode is not None:
             os.chmod(self.journal, createmode & 0666)
 
     def __del__(self):
         if self.journal:
-            if self.entries: self._abort()
-            self.file.close()
+            self._abort()
 
     @active
     def startgroup(self):
         self._queue.append([])
 
     @active
     def endgroup(self):
         q = self._queue.pop()
         d = ''.join(['%s\0%d\n' % (x[0], x[1]) for x in q])
         self.entries.extend(q)
         self.file.write(d)
         self.file.flush()
 
     @active
     def add(self, file, offset, data=None):
         if file in self.map: return
 
         if self._queue:
             self._queue[-1].append((file, offset, data))
             return
 
         self.entries.append((file, offset, data))
         self.map[file] = len(self.entries) - 1
         # add enough data to the journal to do the truncate
         self.file.write("%s\0%d\n" % (file, offset))
         self.file.flush()
 
     @active
     def find(self, file):
         if file in self.map:
             return self.entries[self.map[file]]
         return None
 
     @active
     def replace(self, file, offset, data=None):
         '''
         replace can only replace already committed entries
         that are not pending in the queue
         '''
 
         if file not in self.map:
             raise KeyError(file)
         index = self.map[file]
         self.entries[index] = (file, offset, data)
         self.file.write("%s\0%d\n" % (file, offset))
         self.file.flush()
 
     @active
     def nest(self):
         self.count += 1
         return self
 
     def running(self):
         return self.count > 0
 
     @active
     def close(self):
         '''commit the transaction'''
         self.count -= 1
         if self.count != 0:
             return
         self.file.close()
         self.entries = []
         if self.after:
             self.after()
-        else:
+        if os.path.isfile(self.journal):
             os.unlink(self.journal)
         self.journal = None
 
     @active
     def abort(self):
         '''abort the transaction (generally called on error, or when the
         transaction is not explicitly committed before going out of
         scope)'''
         self._abort()
 
     def _abort(self):
         self.count = 0
         self.file.close()
 
-        if not self.entries: return
+        if not self.entries:
+            if self.journal:
+                os.unlink(self.journal)
+            return
 
         self.report(_("transaction abort!\n"))
 
         try:
             try:
                 _playback(self.journal, self.report, self.opener, self.entries, False)
                 self.report(_("rollback completed\n"))
             except:
                 self.report(_("rollback failed - please run hg recover\n"))
         finally:
             self.journal = None
 
 
 def rollback(opener, file, report):
     entries = []
 
     for l in open(file).readlines():
         f, o = l.split('\0')
         entries.append((f, int(o), None))
 
     _playback(file, report, opener, entries)

tests/test-journal-exists

@@ -1,12 +1,20 b''
 #!/bin/sh
 
 hg init
 echo a > a
 hg ci -Am0
+hg -q clone . foo
 
 touch .hg/store/journal
 
 echo foo > a
 hg ci -Am0
 
 hg recover
+
+echo % check that zero-size journals are correctly aborted
+hg bundle -qa repo.hg
+chmod -w foo/.hg/store/00changelog.i
+hg -R foo unbundle repo.hg 2>&1 | sed 's/\(abort: Permission denied\).*/\1/'
+if test -f foo/.hg/store/journal; then echo 'journal exists :-('; fi
+exit 0

tests/test-journal-exists.out

@@ -1,8 +1,11 b''
 adding a
 abort: abandoned transaction found - run hg recover!
 rolling back interrupted transaction
 checking changesets
 checking manifests
 crosschecking files in changesets and manifests
 checking files
 1 files, 1 changesets, 1 total revisions
+% check that zero-size journals are correctly aborted
+adding changesets
+abort: Permission denied