rebase: take locks in the right order

repo.lock was taken before repo.wlock - that could in principle cause a deadlock.

hgext/rebase.py

@@ -1,645 +1,645 b''
 # rebase.py - rebasing feature for mercurial
 #
 # Copyright 2008 Stefano Tortarolo <stefano.tortarolo at gmail dot com>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 '''command to move sets of revisions to a different ancestor
 
 This extension lets you rebase changesets in an existing Mercurial
 repository.
 
 For more information:
 http://mercurial.selenic.com/wiki/RebaseExtension
 '''
 
 from mercurial import hg, util, repair, merge, cmdutil, commands, bookmarks
 from mercurial import extensions, patch, scmutil
 from mercurial.commands import templateopts
 from mercurial.node import nullrev
 from mercurial.lock import release
 from mercurial.i18n import _
 import os, errno
 
 nullmerge = -2
 
 cmdtable = {}
 command = cmdutil.command(cmdtable)
 
 @command('rebase',
     [('s', 'source', '',
      _('rebase from the specified changeset'), _('REV')),
     ('b', 'base', '',
      _('rebase from the base of the specified changeset '
        '(up to greatest common ancestor of base and dest)'),
      _('REV')),
     ('r', 'rev', [],
      _('rebase these revisions'),
      _('REV')),
     ('d', 'dest', '',
      _('rebase onto the specified changeset'), _('REV')),
     ('', 'collapse', False, _('collapse the rebased changesets')),
     ('m', 'message', '',
      _('use text as collapse commit message'), _('TEXT')),
     ('e', 'edit', False, _('invoke editor on commit messages')),
     ('l', 'logfile', '',
      _('read collapse commit message from file'), _('FILE')),
     ('', 'keep', False, _('keep original changesets')),
     ('', 'keepbranches', False, _('keep original branch names')),
     ('D', 'detach', False, _('force detaching of source from its original '
                             'branch')),
     ('t', 'tool', '', _('specify merge tool')),
     ('c', 'continue', False, _('continue an interrupted rebase')),
     ('a', 'abort', False, _('abort an interrupted rebase'))] +
      templateopts,
     _('hg rebase [-s REV | -b REV] [-d REV] [options]\n'
       'hg rebase {-a|-c}'))
 def rebase(ui, repo, **opts):
     """move changeset (and descendants) to a different branch
 
     Rebase uses repeated merging to graft changesets from one part of
     history (the source) onto another (the destination). This can be
     useful for linearizing *local* changes relative to a master
     development tree.
 
     You should not rebase changesets that have already been shared
     with others. Doing so will force everybody else to perform the
     same rebase or they will end up with duplicated changesets after
     pulling in your rebased changesets.
 
     If you don't specify a destination changeset (``-d/--dest``),
     rebase uses the tipmost head of the current named branch as the
     destination. (The destination changeset is not modified by
     rebasing, but new changesets are added as its descendants.)
 
     You can specify which changesets to rebase in two ways: as a
     "source" changeset or as a "base" changeset. Both are shorthand
     for a topologically related set of changesets (the "source
     branch"). If you specify source (``-s/--source``), rebase will
     rebase that changeset and all of its descendants onto dest. If you
     specify base (``-b/--base``), rebase will select ancestors of base
     back to but not including the common ancestor with dest. Thus,
     ``-b`` is less precise but more convenient than ``-s``: you can
     specify any changeset in the source branch, and rebase will select
     the whole branch. If you specify neither ``-s`` nor ``-b``, rebase
     uses the parent of the working directory as the base.
 
     By default, rebase recreates the changesets in the source branch
     as descendants of dest and then destroys the originals. Use
     ``--keep`` to preserve the original source changesets. Some
     changesets in the source branch (e.g. merges from the destination
     branch) may be dropped if they no longer contribute any change.
 
     One result of the rules for selecting the destination changeset
     and source branch is that, unlike ``merge``, rebase will do
     nothing if you are at the latest (tipmost) head of a named branch
     with two heads. You need to explicitly specify source and/or
     destination (or ``update`` to the other head, if it's the head of
     the intended source branch).
 
     If a rebase is interrupted to manually resolve a merge, it can be
     continued with --continue/-c or aborted with --abort/-a.
 
     Returns 0 on success, 1 if nothing to rebase.
     """
     originalwd = target = None
     external = nullrev
     state = {}
     skipped = set()
     targetancestors = set()
 
     editor = None
     if opts.get('edit'):
         editor = cmdutil.commitforceeditor
 
     lock = wlock = None
     try:
+        wlock = repo.wlock()
         lock = repo.lock()
-        wlock = repo.wlock()
 
         # Validate input and define rebasing points
         destf = opts.get('dest', None)
         srcf = opts.get('source', None)
         basef = opts.get('base', None)
         revf = opts.get('rev', [])
         contf = opts.get('continue')
         abortf = opts.get('abort')
         collapsef = opts.get('collapse', False)
         collapsemsg = cmdutil.logmessage(ui, opts)
         extrafn = opts.get('extrafn') # internal, used by e.g. hgsubversion
         keepf = opts.get('keep', False)
         keepbranchesf = opts.get('keepbranches', False)
         detachf = opts.get('detach', False)
         # keepopen is not meant for use on the command line, but by
         # other extensions
         keepopen = opts.get('keepopen', False)
 
         if collapsemsg and not collapsef:
             raise util.Abort(
                 _('message can only be specified with collapse'))
 
         if contf or abortf:
             if contf and abortf:
                 raise util.Abort(_('cannot use both abort and continue'))
             if collapsef:
                 raise util.Abort(
                     _('cannot use collapse with continue or abort'))
             if detachf:
                 raise util.Abort(_('cannot use detach with continue or abort'))
             if srcf or basef or destf:
                 raise util.Abort(
                     _('abort and continue do not allow specifying revisions'))
             if opts.get('tool', False):
                 ui.warn(_('tool option will be ignored\n'))
 
             (originalwd, target, state, skipped, collapsef, keepf,
                                 keepbranchesf, external) = restorestatus(repo)
             if abortf:
                 return abort(repo, originalwd, target, state)
         else:
             if srcf and basef:
                 raise util.Abort(_('cannot specify both a '
                                    'source and a base'))
             if revf and basef:
                 raise util.Abort(_('cannot specify both a '
                                    'revision and a base'))
             if revf and srcf:
                 raise util.Abort(_('cannot specify both a '
                                    'revision and a source'))
             if detachf:
                 if not (srcf or revf):
                     raise util.Abort(
                         _('detach requires a revision to be specified'))
                 if basef:
                     raise util.Abort(_('cannot specify a base with detach'))
 
             cmdutil.bailifchanged(repo)
 
             if not destf:
                 # Destination defaults to the latest revision in the
                 # current branch
                 branch = repo[None].branch()
                 dest = repo[branch]
             else:
                 dest = repo[destf]
 
             if revf:
                 rebaseset = repo.revs('%lr', revf)
             elif srcf:
                 src = scmutil.revrange(repo, [srcf])
                 rebaseset = repo.revs('(%ld)::', src)
             else:
                 base = scmutil.revrange(repo, [basef or '.'])
                 rebaseset = repo.revs(
                     '(children(ancestor(%ld, %d)) and ::(%ld))::',
                     base, dest, base)
 
             if rebaseset:
                 root = min(rebaseset)
             else:
                 root = None
 
             if not rebaseset:
                 repo.ui.debug('base is ancestor of destination')
                 result = None
             elif not keepf and list(repo.revs('first(children(%ld) - %ld)',
                                               rebaseset, rebaseset)):
                 raise util.Abort(
                     _("can't remove original changesets with"
                       " unrebased descendants"),
                     hint=_('use --keep to keep original changesets'))
             elif not keepf and not repo[root].mutable():
                 raise util.Abort(_("Can't rebase immutable changeset %s")
                                  % repo[root],
                                  hint=_('see hg help phases for details'))
             else:
                 result = buildstate(repo, dest, rebaseset, detachf)
 
             if not result:
                 # Empty state built, nothing to rebase
                 ui.status(_('nothing to rebase\n'))
                 return 1
             else:
                 originalwd, target, state = result
                 if collapsef:
                     targetancestors = set(repo.changelog.ancestors(target))
                     targetancestors.add(target)
                     external = checkexternal(repo, state, targetancestors)
 
         if keepbranchesf:
             assert not extrafn, 'cannot use both keepbranches and extrafn'
             def extrafn(ctx, extra):
                 extra['branch'] = ctx.branch()
             if collapsef:
                 branches = set()
                 for rev in state:
                     branches.add(repo[rev].branch())
                     if len(branches) > 1:
                         raise util.Abort(_('cannot collapse multiple named '
                             'branches'))
 
 
         # Rebase
         if not targetancestors:
             targetancestors = set(repo.changelog.ancestors(target))
             targetancestors.add(target)
 
         # Keep track of the current bookmarks in order to reset them later
         currentbookmarks = repo._bookmarks.copy()
 
         sortedstate = sorted(state)
         total = len(sortedstate)
         pos = 0
         for rev in sortedstate:
             pos += 1
             if state[rev] == -1:
                 ui.progress(_("rebasing"), pos, ("%d:%s" % (rev, repo[rev])),
                             _('changesets'), total)
                 storestatus(repo, originalwd, target, state, collapsef, keepf,
                                                     keepbranchesf, external)
                 p1, p2 = defineparents(repo, rev, target, state,
                                                         targetancestors)
                 if len(repo.parents()) == 2:
                     repo.ui.debug('resuming interrupted rebase\n')
                 else:
                     try:
                         ui.setconfig('ui', 'forcemerge', opts.get('tool', ''))
                         stats = rebasenode(repo, rev, p1, state)
                         if stats and stats[3] > 0:
                             raise util.Abort(_('unresolved conflicts (see hg '
                                         'resolve, then hg rebase --continue)'))
                     finally:
                         ui.setconfig('ui', 'forcemerge', '')
                 cmdutil.duplicatecopies(repo, rev, target)
                 if not collapsef:
                     newrev = concludenode(repo, rev, p1, p2, extrafn=extrafn,
                                           editor=editor)
                 else:
                     # Skip commit if we are collapsing
                     repo.dirstate.setparents(repo[p1].node())
                     newrev = None
                 # Update the state
                 if newrev is not None:
                     state[rev] = repo[newrev].rev()
                 else:
                     if not collapsef:
                         ui.note(_('no changes, revision %d skipped\n') % rev)
                         ui.debug('next revision set to %s\n' % p1)
                         skipped.add(rev)
                     state[rev] = p1
 
         ui.progress(_('rebasing'), None)
         ui.note(_('rebase merging completed\n'))
 
         if collapsef and not keepopen:
             p1, p2 = defineparents(repo, min(state), target,
                                                         state, targetancestors)
             if collapsemsg:
                 commitmsg = collapsemsg
             else:
                 commitmsg = 'Collapsed revision'
                 for rebased in state:
                     if rebased not in skipped and state[rebased] != nullmerge:
                         commitmsg += '\n* %s' % repo[rebased].description()
                 commitmsg = ui.edit(commitmsg, repo.ui.username())
             newrev = concludenode(repo, rev, p1, external, commitmsg=commitmsg,
                                   extrafn=extrafn, editor=editor)
 
         if 'qtip' in repo.tags():
             updatemq(repo, state, skipped, **opts)
 
         if currentbookmarks:
             # Nodeids are needed to reset bookmarks
             nstate = {}
             for k, v in state.iteritems():
                 if v != nullmerge:
                     nstate[repo[k].node()] = repo[v].node()
 
         if not keepf:
             # Remove no more useful revisions
             rebased = [rev for rev in state if state[rev] != nullmerge]
             if rebased:
                 if set(repo.changelog.descendants(min(rebased))) - set(state):
                     ui.warn(_("warning: new changesets detected "
                               "on source branch, not stripping\n"))
                 else:
                     # backup the old csets by default
                     repair.strip(ui, repo, repo[min(rebased)].node(), "all")
 
         if currentbookmarks:
             updatebookmarks(repo, nstate, currentbookmarks, **opts)
 
         clearstatus(repo)
         ui.note(_("rebase completed\n"))
         if os.path.exists(repo.sjoin('undo')):
             util.unlinkpath(repo.sjoin('undo'))
         if skipped:
             ui.note(_("%d revisions have been skipped\n") % len(skipped))
     finally:
         release(lock, wlock)
 
 def checkexternal(repo, state, targetancestors):
     """Check whether one or more external revisions need to be taken in
     consideration. In the latter case, abort.
     """
     external = nullrev
     source = min(state)
     for rev in state:
         if rev == source:
             continue
         # Check externals and fail if there are more than one
         for p in repo[rev].parents():
             if (p.rev() not in state
                         and p.rev() not in targetancestors):
                 if external != nullrev:
                     raise util.Abort(_('unable to collapse, there is more '
                             'than one external parent'))
                 external = p.rev()
     return external
 
 def concludenode(repo, rev, p1, p2, commitmsg=None, editor=None, extrafn=None):
     'Commit the changes and store useful information in extra'
     try:
         repo.dirstate.setparents(repo[p1].node(), repo[p2].node())
         ctx = repo[rev]
         if commitmsg is None:
             commitmsg = ctx.description()
         extra = {'rebase_source': ctx.hex()}
         if extrafn:
             extrafn(ctx, extra)
         # Commit might fail if unresolved files exist
         newrev = repo.commit(text=commitmsg, user=ctx.user(),
                              date=ctx.date(), extra=extra, editor=editor)
         repo.dirstate.setbranch(repo[newrev].branch())
         return newrev
     except util.Abort:
         # Invalidate the previous setparents
         repo.dirstate.invalidate()
         raise
 
 def rebasenode(repo, rev, p1, state):
     'Rebase a single revision'
     # Merge phase
     # Update to target and merge it with local
     if repo['.'].rev() != repo[p1].rev():
         repo.ui.debug(" update to %d:%s\n" % (repo[p1].rev(), repo[p1]))
         merge.update(repo, p1, False, True, False)
     else:
         repo.ui.debug(" already in target\n")
     repo.dirstate.write()
     repo.ui.debug(" merge against %d:%s\n" % (repo[rev].rev(), repo[rev]))
     base = None
     if repo[rev].rev() != repo[min(state)].rev():
         base = repo[rev].p1().node()
     return merge.update(repo, rev, True, True, False, base)
 
 def defineparents(repo, rev, target, state, targetancestors):
     'Return the new parent relationship of the revision that will be rebased'
     parents = repo[rev].parents()
     p1 = p2 = nullrev
 
     P1n = parents[0].rev()
     if P1n in targetancestors:
         p1 = target
     elif P1n in state:
         if state[P1n] == nullmerge:
             p1 = target
         else:
             p1 = state[P1n]
     else: # P1n external
         p1 = target
         p2 = P1n
 
     if len(parents) == 2 and parents[1].rev() not in targetancestors:
         P2n = parents[1].rev()
         # interesting second parent
         if P2n in state:
             if p1 == target: # P1n in targetancestors or external
                 p1 = state[P2n]
             else:
                 p2 = state[P2n]
         else: # P2n external
             if p2 != nullrev: # P1n external too => rev is a merged revision
                 raise util.Abort(_('cannot use revision %d as base, result '
                         'would have 3 parents') % rev)
             p2 = P2n
     repo.ui.debug(" future parents are %d and %d\n" %
                             (repo[p1].rev(), repo[p2].rev()))
     return p1, p2
 
 def isagitpatch(repo, patchname):
     'Return true if the given patch is in git format'
     mqpatch = os.path.join(repo.mq.path, patchname)
     for line in patch.linereader(file(mqpatch, 'rb')):
         if line.startswith('diff --git'):
             return True
     return False
 
 def updatemq(repo, state, skipped, **opts):
     'Update rebased mq patches - finalize and then import them'
     mqrebase = {}
     mq = repo.mq
     original_series = mq.fullseries[:]
 
     for p in mq.applied:
         rev = repo[p.node].rev()
         if rev in state:
             repo.ui.debug('revision %d is an mq patch (%s), finalize it.\n' %
                                         (rev, p.name))
             mqrebase[rev] = (p.name, isagitpatch(repo, p.name))
 
     if mqrebase:
         mq.finish(repo, mqrebase.keys())
 
         # We must start import from the newest revision
         for rev in sorted(mqrebase, reverse=True):
             if rev not in skipped:
                 name, isgit = mqrebase[rev]
                 repo.ui.debug('import mq patch %d (%s)\n' % (state[rev], name))
                 mq.qimport(repo, (), patchname=name, git=isgit,
                                 rev=[str(state[rev])])
 
         # restore old series to preserve guards
         mq.fullseries = original_series
         mq.series_dirty = True
         mq.savedirty()
 
 def updatebookmarks(repo, nstate, originalbookmarks, **opts):
     'Move bookmarks to their correct changesets'
     current = repo._bookmarkcurrent
     for k, v in originalbookmarks.iteritems():
         if v in nstate:
             if nstate[v] != nullmerge:
                 # reset the pointer if the bookmark was moved incorrectly
                 if k != current:
                     repo._bookmarks[k] = nstate[v]
 
     bookmarks.write(repo)
 
 def storestatus(repo, originalwd, target, state, collapse, keep, keepbranches,
                                                                 external):
     'Store the current status to allow recovery'
     f = repo.opener("rebasestate", "w")
     f.write(repo[originalwd].hex() + '\n')
     f.write(repo[target].hex() + '\n')
     f.write(repo[external].hex() + '\n')
     f.write('%d\n' % int(collapse))
     f.write('%d\n' % int(keep))
     f.write('%d\n' % int(keepbranches))
     for d, v in state.iteritems():
         oldrev = repo[d].hex()
         if v != nullmerge:
             newrev = repo[v].hex()
         else:
             newrev = v
         f.write("%s:%s\n" % (oldrev, newrev))
     f.close()
     repo.ui.debug('rebase status stored\n')
 
 def clearstatus(repo):
     'Remove the status files'
     if os.path.exists(repo.join("rebasestate")):
         util.unlinkpath(repo.join("rebasestate"))
 
 def restorestatus(repo):
     'Restore a previously stored status'
     try:
         target = None
         collapse = False
         external = nullrev
         state = {}
         f = repo.opener("rebasestate")
         for i, l in enumerate(f.read().splitlines()):
             if i == 0:
                 originalwd = repo[l].rev()
             elif i == 1:
                 target = repo[l].rev()
             elif i == 2:
                 external = repo[l].rev()
             elif i == 3:
                 collapse = bool(int(l))
             elif i == 4:
                 keep = bool(int(l))
             elif i == 5:
                 keepbranches = bool(int(l))
             else:
                 oldrev, newrev = l.split(':')
                 if newrev != str(nullmerge):
                     state[repo[oldrev].rev()] = repo[newrev].rev()
                 else:
                     state[repo[oldrev].rev()] = int(newrev)
         skipped = set()
         # recompute the set of skipped revs
         if not collapse:
             seen = set([target])
             for old, new in sorted(state.items()):
                 if new != nullrev and new in seen:
                     skipped.add(old)
                 seen.add(new)
         repo.ui.debug('computed skipped revs: %s\n' % skipped)
         repo.ui.debug('rebase status resumed\n')
         return (originalwd, target, state, skipped,
                 collapse, keep, keepbranches, external)
     except IOError, err:
         if err.errno != errno.ENOENT:
             raise
         raise util.Abort(_('no rebase in progress'))
 
 def abort(repo, originalwd, target, state):
     'Restore the repository to its original state'
     if set(repo.changelog.descendants(target)) - set(state.values()):
         repo.ui.warn(_("warning: new changesets detected on target branch, "
                                                     "can't abort\n"))
         return -1
     else:
         # Strip from the first rebased revision
         merge.update(repo, repo[originalwd].rev(), False, True, False)
         rebased = filter(lambda x: x > -1 and x != target, state.values())
         if rebased:
             strippoint = min(rebased)
             # no backup of rebased cset versions needed
             repair.strip(repo.ui, repo, repo[strippoint].node())
         clearstatus(repo)
         repo.ui.warn(_('rebase aborted\n'))
         return 0
 
 def buildstate(repo, dest, rebaseset, detach):
     '''Define which revisions are going to be rebased and where
 
     repo: repo
     dest: context
     rebaseset: set of rev
     detach: boolean'''
 
     # This check isn't strictly necessary, since mq detects commits over an
     # applied patch. But it prevents messing up the working directory when
     # a partially completed rebase is blocked by mq.
     if 'qtip' in repo.tags() and (dest.node() in
                             [s.node for s in repo.mq.applied]):
         raise util.Abort(_('cannot rebase onto an applied mq patch'))
 
     detachset = set()
     roots = list(repo.set('roots(%ld)', rebaseset))
     if not roots:
         raise util.Abort(_('no matching revisions'))
     if len(roots) > 1:
         raise util.Abort(_("can't rebase multiple roots"))
     root = roots[0]
 
     commonbase = root.ancestor(dest)
     if commonbase == root:
         raise util.Abort(_('source is ancestor of destination'))
     if commonbase == dest:
         samebranch = root.branch() == dest.branch()
         if samebranch and root in dest.children():
            repo.ui.debug('source is a child of destination')
            return None
         # rebase on ancestor, force detach
         detach = True
     if detach:
         detachset = repo.revs('::%d - ::%d - %d', root, commonbase, root)
 
     repo.ui.debug('rebase onto %d starting from %d\n' % (dest, root))
     state = dict.fromkeys(rebaseset, nullrev)
     state.update(dict.fromkeys(detachset, nullmerge))
     return repo['.'].rev(), dest.rev(), state
 
 def pullrebase(orig, ui, repo, *args, **opts):
     'Call rebase after pull if the latter has been invoked with --rebase'
     if opts.get('rebase'):
         if opts.get('update'):
             del opts['update']
             ui.debug('--update and --rebase are not compatible, ignoring '
                      'the update flag\n')
 
         cmdutil.bailifchanged(repo)
         revsprepull = len(repo)
         origpostincoming = commands.postincoming
         def _dummy(*args, **kwargs):
             pass
         commands.postincoming = _dummy
         try:
             orig(ui, repo, *args, **opts)
         finally:
             commands.postincoming = origpostincoming
         revspostpull = len(repo)
         if revspostpull > revsprepull:
             rebase(ui, repo, **opts)
             branch = repo[None].branch()
             dest = repo[branch].rev()
             if dest != repo['.'].rev():
                 # there was nothing to rebase we force an update
                 hg.update(repo, dest)
     else:
         if opts.get('tool'):
             raise util.Abort(_('--tool can only be used with --rebase'))
         orig(ui, repo, *args, **opts)
 
 def uisetup(ui):
     'Replace pull with a decorator to provide --rebase option'
     entry = extensions.wrapcommand(commands.table, 'pull', pullrebase)
     entry[1].append(('', 'rebase', None,
                      _("rebase working directory to branch head")))
     entry[1].append(('t', 'tool', '',
                      _("specify merge tool for rebase")))