merge: pass merge ancestor to calculateupdates as a list

The list will so far always have one element.

hgext/largefiles/overrides.py

@@ -1,1164 +1,1164
 # Copyright 2009-2010 Gregory P. Ward
 # Copyright 2009-2010 Intelerad Medical Systems Incorporated
 # Copyright 2010-2011 Fog Creek Software
 # Copyright 2010-2011 Unity Technologies
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 '''Overridden Mercurial commands and functions for the largefiles extension'''
 
 import os
 import copy
 
 from mercurial import hg, commands, util, cmdutil, scmutil, match as match_, \
         archival, merge, pathutil, revset
 from mercurial.i18n import _
 from mercurial.node import hex
 from hgext import rebase
 
 import lfutil
 import lfcommands
 import basestore
 
 # -- Utility functions: commonly/repeatedly needed functionality ---------------
 
 def installnormalfilesmatchfn(manifest):
     '''overrides scmutil.match so that the matcher it returns will ignore all
     largefiles'''
     oldmatch = None # for the closure
     def overridematch(ctx, pats=[], opts={}, globbed=False,
             default='relpath'):
         match = oldmatch(ctx, pats, opts, globbed, default)
         m = copy.copy(match)
         notlfile = lambda f: not (lfutil.isstandin(f) or lfutil.standin(f) in
                 manifest)
         m._files = filter(notlfile, m._files)
         m._fmap = set(m._files)
         m._always = False
         origmatchfn = m.matchfn
         m.matchfn = lambda f: notlfile(f) and origmatchfn(f) or None
         return m
     oldmatch = installmatchfn(overridematch)
 
 def installmatchfn(f):
     oldmatch = scmutil.match
     setattr(f, 'oldmatch', oldmatch)
     scmutil.match = f
     return oldmatch
 
 def restorematchfn():
     '''restores scmutil.match to what it was before installnormalfilesmatchfn
     was called.  no-op if scmutil.match is its original function.
 
     Note that n calls to installnormalfilesmatchfn will require n calls to
     restore matchfn to reverse'''
     scmutil.match = getattr(scmutil.match, 'oldmatch', scmutil.match)
 
 def addlargefiles(ui, repo, *pats, **opts):
     large = opts.pop('large', None)
     lfsize = lfutil.getminsize(
         ui, lfutil.islfilesrepo(repo), opts.pop('lfsize', None))
 
     lfmatcher = None
     if lfutil.islfilesrepo(repo):
         lfpats = ui.configlist(lfutil.longname, 'patterns', default=[])
         if lfpats:
             lfmatcher = match_.match(repo.root, '', list(lfpats))
 
     lfnames = []
     m = scmutil.match(repo[None], pats, opts)
     m.bad = lambda x, y: None
     wctx = repo[None]
     for f in repo.walk(m):
         exact = m.exact(f)
         lfile = lfutil.standin(f) in wctx
         nfile = f in wctx
         exists = lfile or nfile
 
         # Don't warn the user when they attempt to add a normal tracked file.
         # The normal add code will do that for us.
         if exact and exists:
             if lfile:
                 ui.warn(_('%s already a largefile\n') % f)
             continue
 
         if (exact or not exists) and not lfutil.isstandin(f):
             wfile = repo.wjoin(f)
 
             # In case the file was removed previously, but not committed
             # (issue3507)
             if not os.path.exists(wfile):
                 continue
 
             abovemin = (lfsize and
                         os.lstat(wfile).st_size >= lfsize * 1024 * 1024)
             if large or abovemin or (lfmatcher and lfmatcher(f)):
                 lfnames.append(f)
                 if ui.verbose or not exact:
                     ui.status(_('adding %s as a largefile\n') % m.rel(f))
 
     bad = []
     standins = []
 
     # Need to lock, otherwise there could be a race condition between
     # when standins are created and added to the repo.
     wlock = repo.wlock()
     try:
         if not opts.get('dry_run'):
             lfdirstate = lfutil.openlfdirstate(ui, repo)
             for f in lfnames:
                 standinname = lfutil.standin(f)
                 lfutil.writestandin(repo, standinname, hash='',
                     executable=lfutil.getexecutable(repo.wjoin(f)))
                 standins.append(standinname)
                 if lfdirstate[f] == 'r':
                     lfdirstate.normallookup(f)
                 else:
                     lfdirstate.add(f)
             lfdirstate.write()
             bad += [lfutil.splitstandin(f)
                     for f in repo[None].add(standins)
                     if f in m.files()]
     finally:
         wlock.release()
     return bad
 
 def removelargefiles(ui, repo, *pats, **opts):
     after = opts.get('after')
     if not pats and not after:
         raise util.Abort(_('no files specified'))
     m = scmutil.match(repo[None], pats, opts)
     try:
         repo.lfstatus = True
         s = repo.status(match=m, clean=True)
     finally:
         repo.lfstatus = False
     manifest = repo[None].manifest()
     modified, added, deleted, clean = [[f for f in list
                                         if lfutil.standin(f) in manifest]
                                        for list in [s[0], s[1], s[3], s[6]]]
 
     def warn(files, msg):
         for f in files:
             ui.warn(msg % m.rel(f))
         return int(len(files) > 0)
 
     result = 0
 
     if after:
         remove, forget = deleted, []
         result = warn(modified + added + clean,
                       _('not removing %s: file still exists\n'))
     else:
         remove, forget = deleted + clean, []
         result = warn(modified, _('not removing %s: file is modified (use -f'
                                   ' to force removal)\n'))
         result = warn(added, _('not removing %s: file has been marked for add'
                                ' (use forget to undo)\n')) or result
 
     for f in sorted(remove + forget):
         if ui.verbose or not m.exact(f):
             ui.status(_('removing %s\n') % m.rel(f))
 
     # Need to lock because standin files are deleted then removed from the
     # repository and we could race in-between.
     wlock = repo.wlock()
     try:
         lfdirstate = lfutil.openlfdirstate(ui, repo)
         for f in remove:
             if not after:
                 # If this is being called by addremove, notify the user that we
                 # are removing the file.
                 if getattr(repo, "_isaddremove", False):
                     ui.status(_('removing %s\n') % f)
                 util.unlinkpath(repo.wjoin(f), ignoremissing=True)
             lfdirstate.remove(f)
         lfdirstate.write()
         forget = [lfutil.standin(f) for f in forget]
         remove = [lfutil.standin(f) for f in remove]
         repo[None].forget(forget)
         # If this is being called by addremove, let the original addremove
         # function handle this.
         if not getattr(repo, "_isaddremove", False):
             for f in remove:
                 util.unlinkpath(repo.wjoin(f), ignoremissing=True)
         repo[None].forget(remove)
     finally:
         wlock.release()
 
     return result
 
 # For overriding mercurial.hgweb.webcommands so that largefiles will
 # appear at their right place in the manifests.
 def decodepath(orig, path):
     return lfutil.splitstandin(path) or path
 
 # -- Wrappers: modify existing commands --------------------------------
 
 # Add works by going through the files that the user wanted to add and
 # checking if they should be added as largefiles. Then it makes a new
 # matcher which matches only the normal files and runs the original
 # version of add.
 def overrideadd(orig, ui, repo, *pats, **opts):
     normal = opts.pop('normal')
     if normal:
         if opts.get('large'):
             raise util.Abort(_('--normal cannot be used with --large'))
         return orig(ui, repo, *pats, **opts)
     bad = addlargefiles(ui, repo, *pats, **opts)
     installnormalfilesmatchfn(repo[None].manifest())
     result = orig(ui, repo, *pats, **opts)
     restorematchfn()
 
     return (result == 1 or bad) and 1 or 0
 
 def overrideremove(orig, ui, repo, *pats, **opts):
     installnormalfilesmatchfn(repo[None].manifest())
     result = orig(ui, repo, *pats, **opts)
     restorematchfn()
     return removelargefiles(ui, repo, *pats, **opts) or result
 
 def overridestatusfn(orig, repo, rev2, **opts):
     try:
         repo._repo.lfstatus = True
         return orig(repo, rev2, **opts)
     finally:
         repo._repo.lfstatus = False
 
 def overridestatus(orig, ui, repo, *pats, **opts):
     try:
         repo.lfstatus = True
         return orig(ui, repo, *pats, **opts)
     finally:
         repo.lfstatus = False
 
 def overridedirty(orig, repo, ignoreupdate=False):
     try:
         repo._repo.lfstatus = True
         return orig(repo, ignoreupdate)
     finally:
         repo._repo.lfstatus = False
 
 def overridelog(orig, ui, repo, *pats, **opts):
     def overridematch(ctx, pats=[], opts={}, globbed=False,
             default='relpath'):
         """Matcher that merges root directory with .hglf, suitable for log.
         It is still possible to match .hglf directly.
         For any listed files run log on the standin too.
         matchfn tries both the given filename and with .hglf stripped.
         """
         match = oldmatch(ctx, pats, opts, globbed, default)
         m = copy.copy(match)
         for i in range(0, len(m._files)):
             standin = lfutil.standin(m._files[i])
             if standin in repo[ctx.node()]:
                 m._files[i] = standin
         m._fmap = set(m._files)
         m._always = False
         origmatchfn = m.matchfn
         def lfmatchfn(f):
             lf = lfutil.splitstandin(f)
             if lf is not None and origmatchfn(lf):
                 return True
             r = origmatchfn(f)
             return r
         m.matchfn = lfmatchfn
         return m
     oldmatch = installmatchfn(overridematch)
     try:
         repo.lfstatus = True
         return orig(ui, repo, *pats, **opts)
     finally:
         repo.lfstatus = False
         restorematchfn()
 
 def overrideverify(orig, ui, repo, *pats, **opts):
     large = opts.pop('large', False)
     all = opts.pop('lfa', False)
     contents = opts.pop('lfc', False)
 
     result = orig(ui, repo, *pats, **opts)
     if large or all or contents:
         result = result or lfcommands.verifylfiles(ui, repo, all, contents)
     return result
 
 def overridedebugstate(orig, ui, repo, *pats, **opts):
     large = opts.pop('large', False)
     if large:
         lfcommands.debugdirstate(ui, repo)
     else:
         orig(ui, repo, *pats, **opts)
 
 # Override needs to refresh standins so that update's normal merge
 # will go through properly. Then the other update hook (overriding repo.update)
 # will get the new files. Filemerge is also overridden so that the merge
 # will merge standins correctly.
 def overrideupdate(orig, ui, repo, *pats, **opts):
     lfdirstate = lfutil.openlfdirstate(ui, repo)
     s = lfdirstate.status(match_.always(repo.root, repo.getcwd()), [], False,
         False, False)
     (unsure, modified, added, removed, missing, unknown, ignored, clean) = s
 
     # Need to lock between the standins getting updated and their
     # largefiles getting updated
     wlock = repo.wlock()
     try:
         if opts['check']:
             mod = len(modified) > 0
             for lfile in unsure:
                 standin = lfutil.standin(lfile)
                 if repo['.'][standin].data().strip() != \
                         lfutil.hashfile(repo.wjoin(lfile)):
                     mod = True
                 else:
                     lfdirstate.normal(lfile)
             lfdirstate.write()
             if mod:
                 raise util.Abort(_('uncommitted changes'))
         # XXX handle removed differently
         if not opts['clean']:
             for lfile in unsure + modified + added:
                 lfutil.updatestandin(repo, lfutil.standin(lfile))
     finally:
         wlock.release()
     return orig(ui, repo, *pats, **opts)
 
 # Before starting the manifest merge, merge.updates will call
 # _checkunknown to check if there are any files in the merged-in
 # changeset that collide with unknown files in the working copy.
 #
 # The largefiles are seen as unknown, so this prevents us from merging
 # in a file 'foo' if we already have a largefile with the same name.
 #
 # The overridden function filters the unknown files by removing any
 # largefiles. This makes the merge proceed and we can then handle this
 # case further in the overridden manifestmerge function below.
 def overridecheckunknownfile(origfn, repo, wctx, mctx, f):
     if lfutil.standin(repo.dirstate.normalize(f)) in wctx:
         return False
     return origfn(repo, wctx, mctx, f)
 
 # The manifest merge handles conflicts on the manifest level. We want
 # to handle changes in largefile-ness of files at this level too.
 #
 # The strategy is to run the original manifestmerge and then process
 # the action list it outputs. There are two cases we need to deal with:
 #
 # 1. Normal file in p1, largefile in p2. Here the largefile is
 #    detected via its standin file, which will enter the working copy
 #    with a "get" action. It is not "merge" since the standin is all
 #    Mercurial is concerned with at this level -- the link to the
 #    existing normal file is not relevant here.
 #
 # 2. Largefile in p1, normal file in p2. Here we get a "merge" action
 #    since the largefile will be present in the working copy and
 #    different from the normal file in p2. Mercurial therefore
 #    triggers a merge action.
 #
 # In both cases, we prompt the user and emit new actions to either
 # remove the standin (if the normal file was kept) or to remove the
 # normal file and get the standin (if the largefile was kept). The
 # default prompt answer is to use the largefile version since it was
 # presumably changed on purpose.
 #
 # Finally, the merge.applyupdates function will then take care of
 # writing the files into the working copy and lfcommands.updatelfiles
 # will update the largefiles.
-def overridecalculateupdates(origfn, repo, p1, p2, pa, branchmerge, force,
+def overridecalculateupdates(origfn, repo, p1, p2, pas, branchmerge, force,
                              partial, acceptremote, followcopies):
     overwrite = force and not branchmerge
-    actions = origfn(repo, p1, p2, pa, branchmerge, force, partial,
+    actions = origfn(repo, p1, p2, pas, branchmerge, force, partial,
                      acceptremote, followcopies)
 
     if overwrite:
         return actions
 
     removes = set(a[0] for a in actions if a[1] == 'r')
     processed = []
 
     for action in actions:
         f, m, args, msg = action
 
         splitstandin = f and lfutil.splitstandin(f)
         if (m == "g" and splitstandin is not None and
             splitstandin in p1 and splitstandin not in removes):
             # Case 1: normal file in the working copy, largefile in
             # the second parent
             lfile = splitstandin
             standin = f
             msg = _('remote turned local normal file %s into a largefile\n'
                     'use (l)argefile or keep (n)ormal file?'
                     '$$ &Largefile $$ &Normal file') % lfile
             if repo.ui.promptchoice(msg, 0) == 0:
                 processed.append((lfile, "r", None, msg))
                 processed.append((standin, "g", (p2.flags(standin),), msg))
             else:
                 processed.append((standin, "r", None, msg))
         elif (m == "g" and
             lfutil.standin(f) in p1 and lfutil.standin(f) not in removes):
             # Case 2: largefile in the working copy, normal file in
             # the second parent
             standin = lfutil.standin(f)
             lfile = f
             msg = _('remote turned local largefile %s into a normal file\n'
                     'keep (l)argefile or use (n)ormal file?'
                     '$$ &Largefile $$ &Normal file') % lfile
             if repo.ui.promptchoice(msg, 0) == 0:
                 processed.append((lfile, "r", None, msg))
             else:
                 processed.append((standin, "r", None, msg))
                 processed.append((lfile, "g", (p2.flags(lfile),), msg))
         else:
             processed.append(action)
 
     return processed
 
 # Override filemerge to prompt the user about how they wish to merge
 # largefiles. This will handle identical edits without prompting the user.
 def overridefilemerge(origfn, repo, mynode, orig, fcd, fco, fca):
     if not lfutil.isstandin(orig):
         return origfn(repo, mynode, orig, fcd, fco, fca)
 
     ahash = fca.data().strip().lower()
     dhash = fcd.data().strip().lower()
     ohash = fco.data().strip().lower()
     if (ohash != ahash and
         ohash != dhash and
         (dhash == ahash or
          repo.ui.promptchoice(
              _('largefile %s has a merge conflict\nancestor was %s\n'
                'keep (l)ocal %s or\ntake (o)ther %s?'
                '$$ &Local $$ &Other') %
                (lfutil.splitstandin(orig), ahash, dhash, ohash),
              0) == 1)):
         repo.wwrite(fcd.path(), fco.data(), fco.flags())
     return 0
 
 # Copy first changes the matchers to match standins instead of
 # largefiles.  Then it overrides util.copyfile in that function it
 # checks if the destination largefile already exists. It also keeps a
 # list of copied files so that the largefiles can be copied and the
 # dirstate updated.
 def overridecopy(orig, ui, repo, pats, opts, rename=False):
     # doesn't remove largefile on rename
     if len(pats) < 2:
         # this isn't legal, let the original function deal with it
         return orig(ui, repo, pats, opts, rename)
 
     def makestandin(relpath):
         path = pathutil.canonpath(repo.root, repo.getcwd(), relpath)
         return os.path.join(repo.wjoin(lfutil.standin(path)))
 
     fullpats = scmutil.expandpats(pats)
     dest = fullpats[-1]
 
     if os.path.isdir(dest):
         if not os.path.isdir(makestandin(dest)):
             os.makedirs(makestandin(dest))
     # This could copy both lfiles and normal files in one command,
     # but we don't want to do that. First replace their matcher to
     # only match normal files and run it, then replace it to just
     # match largefiles and run it again.
     nonormalfiles = False
     nolfiles = False
     try:
         try:
             installnormalfilesmatchfn(repo[None].manifest())
             result = orig(ui, repo, pats, opts, rename)
         except util.Abort, e:
             if str(e) != _('no files to copy'):
                 raise e
             else:
                 nonormalfiles = True
             result = 0
     finally:
         restorematchfn()
 
     # The first rename can cause our current working directory to be removed.
     # In that case there is nothing left to copy/rename so just quit.
     try:
         repo.getcwd()
     except OSError:
         return result
 
     try:
         try:
             # When we call orig below it creates the standins but we don't add
             # them to the dir state until later so lock during that time.
             wlock = repo.wlock()
 
             manifest = repo[None].manifest()
             oldmatch = None # for the closure
             def overridematch(ctx, pats=[], opts={}, globbed=False,
                     default='relpath'):
                 newpats = []
                 # The patterns were previously mangled to add the standin
                 # directory; we need to remove that now
                 for pat in pats:
                     if match_.patkind(pat) is None and lfutil.shortname in pat:
                         newpats.append(pat.replace(lfutil.shortname, ''))
                     else:
                         newpats.append(pat)
                 match = oldmatch(ctx, newpats, opts, globbed, default)
                 m = copy.copy(match)
                 lfile = lambda f: lfutil.standin(f) in manifest
                 m._files = [lfutil.standin(f) for f in m._files if lfile(f)]
                 m._fmap = set(m._files)
                 m._always = False
                 origmatchfn = m.matchfn
                 m.matchfn = lambda f: (lfutil.isstandin(f) and
                                     (f in manifest) and
                                     origmatchfn(lfutil.splitstandin(f)) or
                                     None)
                 return m
             oldmatch = installmatchfn(overridematch)
             listpats = []
             for pat in pats:
                 if match_.patkind(pat) is not None:
                     listpats.append(pat)
                 else:
                     listpats.append(makestandin(pat))
 
             try:
                 origcopyfile = util.copyfile
                 copiedfiles = []
                 def overridecopyfile(src, dest):
                     if (lfutil.shortname in src and
                         dest.startswith(repo.wjoin(lfutil.shortname))):
                         destlfile = dest.replace(lfutil.shortname, '')
                         if not opts['force'] and os.path.exists(destlfile):
                             raise IOError('',
                                 _('destination largefile already exists'))
                     copiedfiles.append((src, dest))
                     origcopyfile(src, dest)
 
                 util.copyfile = overridecopyfile
                 result += orig(ui, repo, listpats, opts, rename)
             finally:
                 util.copyfile = origcopyfile
 
             lfdirstate = lfutil.openlfdirstate(ui, repo)
             for (src, dest) in copiedfiles:
                 if (lfutil.shortname in src and
                     dest.startswith(repo.wjoin(lfutil.shortname))):
                     srclfile = src.replace(repo.wjoin(lfutil.standin('')), '')
                     destlfile = dest.replace(repo.wjoin(lfutil.standin('')), '')
                     destlfiledir = os.path.dirname(repo.wjoin(destlfile)) or '.'
                     if not os.path.isdir(destlfiledir):
                         os.makedirs(destlfiledir)
                     if rename:
                         os.rename(repo.wjoin(srclfile), repo.wjoin(destlfile))
                         lfdirstate.remove(srclfile)
                     else:
                         util.copyfile(repo.wjoin(srclfile),
                                       repo.wjoin(destlfile))
 
                     lfdirstate.add(destlfile)
             lfdirstate.write()
         except util.Abort, e:
             if str(e) != _('no files to copy'):
                 raise e
             else:
                 nolfiles = True
     finally:
         restorematchfn()
         wlock.release()
 
     if nolfiles and nonormalfiles:
         raise util.Abort(_('no files to copy'))
 
     return result
 
 # When the user calls revert, we have to be careful to not revert any
 # changes to other largefiles accidentally. This means we have to keep
 # track of the largefiles that are being reverted so we only pull down
 # the necessary largefiles.
 #
 # Standins are only updated (to match the hash of largefiles) before
 # commits. Update the standins then run the original revert, changing
 # the matcher to hit standins instead of largefiles. Based on the
 # resulting standins update the largefiles. Then return the standins
 # to their proper state
 def overriderevert(orig, ui, repo, *pats, **opts):
     # Because we put the standins in a bad state (by updating them)
     # and then return them to a correct state we need to lock to
     # prevent others from changing them in their incorrect state.
     wlock = repo.wlock()
     try:
         lfdirstate = lfutil.openlfdirstate(ui, repo)
         (modified, added, removed, missing, unknown, ignored, clean) = \
             lfutil.lfdirstatestatus(lfdirstate, repo, repo['.'].rev())
         lfdirstate.write()
         for lfile in modified:
             lfutil.updatestandin(repo, lfutil.standin(lfile))
         for lfile in missing:
             if (os.path.exists(repo.wjoin(lfutil.standin(lfile)))):
                 os.unlink(repo.wjoin(lfutil.standin(lfile)))
 
         try:
             ctx = scmutil.revsingle(repo, opts.get('rev'))
             oldmatch = None # for the closure
             def overridematch(ctx, pats=[], opts={}, globbed=False,
                     default='relpath'):
                 match = oldmatch(ctx, pats, opts, globbed, default)
                 m = copy.copy(match)
                 def tostandin(f):
                     if lfutil.standin(f) in ctx:
                         return lfutil.standin(f)
                     elif lfutil.standin(f) in repo[None]:
                         return None
                     return f
                 m._files = [tostandin(f) for f in m._files]
                 m._files = [f for f in m._files if f is not None]
                 m._fmap = set(m._files)
                 m._always = False
                 origmatchfn = m.matchfn
                 def matchfn(f):
                     if lfutil.isstandin(f):
                         # We need to keep track of what largefiles are being
                         # matched so we know which ones to update later --
                         # otherwise we accidentally revert changes to other
                         # largefiles. This is repo-specific, so duckpunch the
                         # repo object to keep the list of largefiles for us
                         # later.
                         if origmatchfn(lfutil.splitstandin(f)) and \
                                 (f in repo[None] or f in ctx):
                             lfileslist = getattr(repo, '_lfilestoupdate', [])
                             lfileslist.append(lfutil.splitstandin(f))
                             repo._lfilestoupdate = lfileslist
                             return True
                         else:
                             return False
                     return origmatchfn(f)
                 m.matchfn = matchfn
                 return m
             oldmatch = installmatchfn(overridematch)
             scmutil.match
             matches = overridematch(repo[None], pats, opts)
             orig(ui, repo, *pats, **opts)
         finally:
             restorematchfn()
         lfileslist = getattr(repo, '_lfilestoupdate', [])
         lfcommands.updatelfiles(ui, repo, filelist=lfileslist,
                                 printmessage=False)
 
         # empty out the largefiles list so we start fresh next time
         repo._lfilestoupdate = []
         for lfile in modified:
             if lfile in lfileslist:
                 if os.path.exists(repo.wjoin(lfutil.standin(lfile))) and lfile\
                         in repo['.']:
                     lfutil.writestandin(repo, lfutil.standin(lfile),
                         repo['.'][lfile].data().strip(),
                         'x' in repo['.'][lfile].flags())
         lfdirstate = lfutil.openlfdirstate(ui, repo)
         for lfile in added:
             standin = lfutil.standin(lfile)
             if standin not in ctx and (standin in matches or opts.get('all')):
                 if lfile in lfdirstate:
                     lfdirstate.drop(lfile)
                 util.unlinkpath(repo.wjoin(standin))
         lfdirstate.write()
     finally:
         wlock.release()
 
 def hgupdaterepo(orig, repo, node, overwrite):
     if not overwrite:
         # Only call updatelfiles on the standins that have changed to save time
         oldstandins = lfutil.getstandinsstate(repo)
 
     result = orig(repo, node, overwrite)
 
     filelist = None
     if not overwrite:
         newstandins = lfutil.getstandinsstate(repo)
         filelist = lfutil.getlfilestoupdate(oldstandins, newstandins)
     lfcommands.updatelfiles(repo.ui, repo, filelist=filelist)
     return result
 
 def hgmerge(orig, repo, node, force=None, remind=True):
     result = orig(repo, node, force, remind)
     lfcommands.updatelfiles(repo.ui, repo)
     return result
 
 # When we rebase a repository with remotely changed largefiles, we need to
 # take some extra care so that the largefiles are correctly updated in the
 # working copy
 def overridepull(orig, ui, repo, source=None, **opts):
     revsprepull = len(repo)
     if not source:
         source = 'default'
     repo.lfpullsource = source
     if opts.get('rebase', False):
         repo._isrebasing = True
         try:
             if opts.get('update'):
                 del opts['update']
                 ui.debug('--update and --rebase are not compatible, ignoring '
                          'the update flag\n')
             del opts['rebase']
             origpostincoming = commands.postincoming
             def _dummy(*args, **kwargs):
                 pass
             commands.postincoming = _dummy
             try:
                 result = commands.pull(ui, repo, source, **opts)
             finally:
                 commands.postincoming = origpostincoming
             revspostpull = len(repo)
             if revspostpull > revsprepull:
                 result = result or rebase.rebase(ui, repo)
         finally:
             repo._isrebasing = False
     else:
         result = orig(ui, repo, source, **opts)
     revspostpull = len(repo)
     lfrevs = opts.get('lfrev', [])
     if opts.get('all_largefiles'):
         lfrevs.append('pulled()')
     if lfrevs and revspostpull > revsprepull:
         numcached = 0
         repo.firstpulled = revsprepull # for pulled() revset expression
         try:
             for rev in scmutil.revrange(repo, lfrevs):
                 ui.note(_('pulling largefiles for revision %s\n') % rev)
                 (cached, missing) = lfcommands.cachelfiles(ui, repo, rev)
                 numcached += len(cached)
         finally:
             del repo.firstpulled
         ui.status(_("%d largefiles cached\n") % numcached)
     return result
 
 def pulledrevsetsymbol(repo, subset, x):
     """``pulled()``
     Changesets that just has been pulled.
 
     Only available with largefiles from pull --lfrev expressions.
 
     .. container:: verbose
 
       Some examples:
 
       - pull largefiles for all new changesets::
 
           hg pull -lfrev "pulled()"
 
       - pull largefiles for all new branch heads::
 
           hg pull -lfrev "head(pulled()) and not closed()"
 
     """
 
     try:
         firstpulled = repo.firstpulled
     except AttributeError:
         raise util.Abort(_("pulled() only available in --lfrev"))
     return revset.baseset([r for r in subset if r >= firstpulled])
 
 def overrideclone(orig, ui, source, dest=None, **opts):
     d = dest
     if d is None:
         d = hg.defaultdest(source)
     if opts.get('all_largefiles') and not hg.islocal(d):
             raise util.Abort(_(
             '--all-largefiles is incompatible with non-local destination %s' %
             d))
 
     return orig(ui, source, dest, **opts)
 
 def hgclone(orig, ui, opts, *args, **kwargs):
     result = orig(ui, opts, *args, **kwargs)
 
     if result is not None:
         sourcerepo, destrepo = result
         repo = destrepo.local()
 
         # Caching is implicitly limited to 'rev' option, since the dest repo was
         # truncated at that point.  The user may expect a download count with
         # this option, so attempt whether or not this is a largefile repo.
         if opts.get('all_largefiles'):
             success, missing = lfcommands.downloadlfiles(ui, repo, None)
 
             if missing != 0:
                 return None
 
     return result
 
 def overriderebase(orig, ui, repo, **opts):
     repo._isrebasing = True
     try:
         return orig(ui, repo, **opts)
     finally:
         repo._isrebasing = False
 
 def overridearchive(orig, repo, dest, node, kind, decode=True, matchfn=None,
             prefix=None, mtime=None, subrepos=None):
     # No need to lock because we are only reading history and
     # largefile caches, neither of which are modified.
     lfcommands.cachelfiles(repo.ui, repo, node)
 
     if kind not in archival.archivers:
         raise util.Abort(_("unknown archive type '%s'") % kind)
 
     ctx = repo[node]
 
     if kind == 'files':
         if prefix:
             raise util.Abort(
                 _('cannot give prefix when archiving to files'))
     else:
         prefix = archival.tidyprefix(dest, kind, prefix)
 
     def write(name, mode, islink, getdata):
         if matchfn and not matchfn(name):
             return
         data = getdata()
         if decode:
             data = repo.wwritedata(name, data)
         archiver.addfile(prefix + name, mode, islink, data)
 
     archiver = archival.archivers[kind](dest, mtime or ctx.date()[0])
 
     if repo.ui.configbool("ui", "archivemeta", True):
         def metadata():
             base = 'repo: %s\nnode: %s\nbranch: %s\n' % (
                 hex(repo.changelog.node(0)), hex(node), ctx.branch())
 
             tags = ''.join('tag: %s\n' % t for t in ctx.tags()
                            if repo.tagtype(t) == 'global')
             if not tags:
                 repo.ui.pushbuffer()
                 opts = {'template': '{latesttag}\n{latesttagdistance}',
                         'style': '', 'patch': None, 'git': None}
                 cmdutil.show_changeset(repo.ui, repo, opts).show(ctx)
                 ltags, dist = repo.ui.popbuffer().split('\n')
                 tags = ''.join('latesttag: %s\n' % t for t in ltags.split(':'))
                 tags += 'latesttagdistance: %s\n' % dist
 
             return base + tags
 
         write('.hg_archival.txt', 0644, False, metadata)
 
     for f in ctx:
         ff = ctx.flags(f)
         getdata = ctx[f].data
         if lfutil.isstandin(f):
             path = lfutil.findfile(repo, getdata().strip())
             if path is None:
                 raise util.Abort(
                     _('largefile %s not found in repo store or system cache')
                     % lfutil.splitstandin(f))
             f = lfutil.splitstandin(f)
 
             def getdatafn():
                 fd = None
                 try:
                     fd = open(path, 'rb')
                     return fd.read()
                 finally:
                     if fd:
                         fd.close()
 
             getdata = getdatafn
         write(f, 'x' in ff and 0755 or 0644, 'l' in ff, getdata)
 
     if subrepos:
         for subpath in sorted(ctx.substate):
             sub = ctx.sub(subpath)
             submatch = match_.narrowmatcher(subpath, matchfn)
             sub.archive(repo.ui, archiver, prefix, submatch)
 
     archiver.done()
 
 def hgsubrepoarchive(orig, repo, ui, archiver, prefix, match=None):
     repo._get(repo._state + ('hg',))
     rev = repo._state[1]
     ctx = repo._repo[rev]
 
     lfcommands.cachelfiles(ui, repo._repo, ctx.node())
 
     def write(name, mode, islink, getdata):
         # At this point, the standin has been replaced with the largefile name,
         # so the normal matcher works here without the lfutil variants.
         if match and not match(f):
             return
         data = getdata()
 
         archiver.addfile(prefix + repo._path + '/' + name, mode, islink, data)
 
     for f in ctx:
         ff = ctx.flags(f)
         getdata = ctx[f].data
         if lfutil.isstandin(f):
             path = lfutil.findfile(repo._repo, getdata().strip())
             if path is None:
                 raise util.Abort(
                     _('largefile %s not found in repo store or system cache')
                     % lfutil.splitstandin(f))
             f = lfutil.splitstandin(f)
 
             def getdatafn():
                 fd = None
                 try:
                     fd = open(os.path.join(prefix, path), 'rb')
                     return fd.read()
                 finally:
                     if fd:
                         fd.close()
 
             getdata = getdatafn
 
         write(f, 'x' in ff and 0755 or 0644, 'l' in ff, getdata)
 
     for subpath in sorted(ctx.substate):
         sub = ctx.sub(subpath)
         submatch = match_.narrowmatcher(subpath, match)
         sub.archive(ui, archiver, os.path.join(prefix, repo._path) + '/',
                     submatch)
 
 # If a largefile is modified, the change is not reflected in its
 # standin until a commit. cmdutil.bailifchanged() raises an exception
 # if the repo has uncommitted changes. Wrap it to also check if
 # largefiles were changed. This is used by bisect and backout.
 def overridebailifchanged(orig, repo):
     orig(repo)
     repo.lfstatus = True
     modified, added, removed, deleted = repo.status()[:4]
     repo.lfstatus = False
     if modified or added or removed or deleted:
         raise util.Abort(_('uncommitted changes'))
 
 # Fetch doesn't use cmdutil.bailifchanged so override it to add the check
 def overridefetch(orig, ui, repo, *pats, **opts):
     repo.lfstatus = True
     modified, added, removed, deleted = repo.status()[:4]
     repo.lfstatus = False
     if modified or added or removed or deleted:
         raise util.Abort(_('uncommitted changes'))
     return orig(ui, repo, *pats, **opts)
 
 def overrideforget(orig, ui, repo, *pats, **opts):
     installnormalfilesmatchfn(repo[None].manifest())
     result = orig(ui, repo, *pats, **opts)
     restorematchfn()
     m = scmutil.match(repo[None], pats, opts)
 
     try:
         repo.lfstatus = True
         s = repo.status(match=m, clean=True)
     finally:
         repo.lfstatus = False
     forget = sorted(s[0] + s[1] + s[3] + s[6])
     forget = [f for f in forget if lfutil.standin(f) in repo[None].manifest()]
 
     for f in forget:
         if lfutil.standin(f) not in repo.dirstate and not \
                 os.path.isdir(m.rel(lfutil.standin(f))):
             ui.warn(_('not removing %s: file is already untracked\n')
                     % m.rel(f))
             result = 1
 
     for f in forget:
         if ui.verbose or not m.exact(f):
             ui.status(_('removing %s\n') % m.rel(f))
 
     # Need to lock because standin files are deleted then removed from the
     # repository and we could race in-between.
     wlock = repo.wlock()
     try:
         lfdirstate = lfutil.openlfdirstate(ui, repo)
         for f in forget:
             if lfdirstate[f] == 'a':
                 lfdirstate.drop(f)
             else:
                 lfdirstate.remove(f)
         lfdirstate.write()
         standins = [lfutil.standin(f) for f in forget]
         for f in standins:
             util.unlinkpath(repo.wjoin(f), ignoremissing=True)
         repo[None].forget(standins)
     finally:
         wlock.release()
 
     return result
 
 def outgoinghook(ui, repo, other, opts, missing):
     if opts.pop('large', None):
         toupload = set()
         lfutil.getlfilestoupload(repo, missing,
                                  lambda fn, lfhash: toupload.add(fn))
         if not toupload:
             ui.status(_('largefiles: no files to upload\n'))
         else:
             ui.status(_('largefiles to upload:\n'))
             for file in sorted(toupload):
                 ui.status(lfutil.splitstandin(file) + '\n')
             ui.status('\n')
 
 def summaryremotehook(ui, repo, opts, changes):
     largeopt = opts.get('large', False)
     if changes is None:
         if largeopt:
             return (False, True) # only outgoing check is needed
         else:
             return (False, False)
     elif largeopt:
         url, branch, peer, outgoing = changes[1]
         if peer is None:
             # i18n: column positioning for "hg summary"
             ui.status(_('largefiles: (no remote repo)\n'))
             return
 
         toupload = set()
         lfutil.getlfilestoupload(repo, outgoing.missing,
                                  lambda fn, lfhash: toupload.add(fn))
         if not toupload:
             # i18n: column positioning for "hg summary"
             ui.status(_('largefiles: (no files to upload)\n'))
         else:
             # i18n: column positioning for "hg summary"
             ui.status(_('largefiles: %d to upload\n') % len(toupload))
 
 def overridesummary(orig, ui, repo, *pats, **opts):
     try:
         repo.lfstatus = True
         orig(ui, repo, *pats, **opts)
     finally:
         repo.lfstatus = False
 
 def scmutiladdremove(orig, repo, pats=[], opts={}, dry_run=None,
                      similarity=None):
     if not lfutil.islfilesrepo(repo):
         return orig(repo, pats, opts, dry_run, similarity)
     # Get the list of missing largefiles so we can remove them
     lfdirstate = lfutil.openlfdirstate(repo.ui, repo)
     s = lfdirstate.status(match_.always(repo.root, repo.getcwd()), [], False,
         False, False)
     (unsure, modified, added, removed, missing, unknown, ignored, clean) = s
 
     # Call into the normal remove code, but the removing of the standin, we want
     # to have handled by original addremove.  Monkey patching here makes sure
     # we don't remove the standin in the largefiles code, preventing a very
     # confused state later.
     if missing:
         m = [repo.wjoin(f) for f in missing]
         repo._isaddremove = True
         removelargefiles(repo.ui, repo, *m, **opts)
         repo._isaddremove = False
     # Call into the normal add code, and any files that *should* be added as
     # largefiles will be
     addlargefiles(repo.ui, repo, *pats, **opts)
     # Now that we've handled largefiles, hand off to the original addremove
     # function to take care of the rest.  Make sure it doesn't do anything with
     # largefiles by installing a matcher that will ignore them.
     installnormalfilesmatchfn(repo[None].manifest())
     result = orig(repo, pats, opts, dry_run, similarity)
     restorematchfn()
     return result
 
 # Calling purge with --all will cause the largefiles to be deleted.
 # Override repo.status to prevent this from happening.
 def overridepurge(orig, ui, repo, *dirs, **opts):
     # XXX large file status is buggy when used on repo proxy.
     # XXX this needs to be investigate.
     repo = repo.unfiltered()
     oldstatus = repo.status
     def overridestatus(node1='.', node2=None, match=None, ignored=False,
                         clean=False, unknown=False, listsubrepos=False):
         r = oldstatus(node1, node2, match, ignored, clean, unknown,
                       listsubrepos)
         lfdirstate = lfutil.openlfdirstate(ui, repo)
         modified, added, removed, deleted, unknown, ignored, clean = r
         unknown = [f for f in unknown if lfdirstate[f] == '?']
         ignored = [f for f in ignored if lfdirstate[f] == '?']
         return modified, added, removed, deleted, unknown, ignored, clean
     repo.status = overridestatus
     orig(ui, repo, *dirs, **opts)
     repo.status = oldstatus
 
 def overriderollback(orig, ui, repo, **opts):
     result = orig(ui, repo, **opts)
     merge.update(repo, node=None, branchmerge=False, force=True,
         partial=lfutil.isstandin)
     wlock = repo.wlock()
     try:
         lfdirstate = lfutil.openlfdirstate(ui, repo)
         lfiles = lfutil.listlfiles(repo)
         oldlfiles = lfutil.listlfiles(repo, repo[None].parents()[0].rev())
         for file in lfiles:
             if file in oldlfiles:
                 lfdirstate.normallookup(file)
             else:
                 lfdirstate.add(file)
         lfdirstate.write()
     finally:
         wlock.release()
     return result
 
 def overridetransplant(orig, ui, repo, *revs, **opts):
     try:
         oldstandins = lfutil.getstandinsstate(repo)
         repo._istransplanting = True
         result = orig(ui, repo, *revs, **opts)
         newstandins = lfutil.getstandinsstate(repo)
         filelist = lfutil.getlfilestoupdate(oldstandins, newstandins)
         lfcommands.updatelfiles(repo.ui, repo, filelist=filelist,
                                 printmessage=True)
     finally:
         repo._istransplanting = False
     return result
 
 def overridecat(orig, ui, repo, file1, *pats, **opts):
     ctx = scmutil.revsingle(repo, opts.get('rev'))
     err = 1
     notbad = set()
     m = scmutil.match(ctx, (file1,) + pats, opts)
     origmatchfn = m.matchfn
     def lfmatchfn(f):
         lf = lfutil.splitstandin(f)
         if lf is None:
             return origmatchfn(f)
         notbad.add(lf)
         return origmatchfn(lf)
     m.matchfn = lfmatchfn
     origbadfn = m.bad
     def lfbadfn(f, msg):
         if not f in notbad:
             return origbadfn(f, msg)
     m.bad = lfbadfn
     for f in ctx.walk(m):
         fp = cmdutil.makefileobj(repo, opts.get('output'), ctx.node(),
                                  pathname=f)
         lf = lfutil.splitstandin(f)
         if lf is None:
             # duplicating unreachable code from commands.cat
             data = ctx[f].data()
             if opts.get('decode'):
                 data = repo.wwritedata(f, data)
             fp.write(data)
         else:
             hash = lfutil.readstandin(repo, lf, ctx.rev())
             if not lfutil.inusercache(repo.ui, hash):
                 store = basestore._openstore(repo)
                 success, missing = store.get([(lf, hash)])
                 if len(success) != 1:
                     raise util.Abort(
                         _('largefile %s is not in cache and could not be '
                           'downloaded')  % lf)
             path = lfutil.usercachepath(repo.ui, hash)
             fpin = open(path, "rb")
             for chunk in util.filechunkiter(fpin, 128 * 1024):
                 fp.write(chunk)
             fpin.close()
         fp.close()
         err = 0
     return err
 
 def mercurialsinkbefore(orig, sink):
     sink.repo._isconverting = True
     orig(sink)
 
 def mercurialsinkafter(orig, sink):
     sink.repo._isconverting = False
     orig(sink)

mercurial/merge.py

@@ -1,1019 +1,1021
 # merge.py - directory-level update/merge handling for Mercurial
 #
 # Copyright 2006, 2007 Matt Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 import struct
 
 from node import nullid, nullrev, hex, bin
 from i18n import _
 from mercurial import obsolete
 import error, util, filemerge, copies, subrepo, worker, dicthelpers
 import errno, os, shutil
 
 _pack = struct.pack
 _unpack = struct.unpack
 
 def _droponode(data):
     # used for compatibility for v1
     bits = data.split("\0")
     bits = bits[:-2] + bits[-1:]
     return "\0".join(bits)
 
 class mergestate(object):
     '''track 3-way merge state of individual files
 
     it is stored on disk when needed. Two file are used, one with an old
     format, one with a new format. Both contains similar data, but the new
     format can store new kind of field.
 
     Current new format is a list of arbitrary record of the form:
 
         [type][length][content]
 
     Type is a single character, length is a 4 bytes integer, content is an
     arbitrary suites of bytes of length `length`.
 
     Type should be a letter. Capital letter are mandatory record, Mercurial
     should abort if they are unknown. lower case record can be safely ignored.
 
     Currently known record:
 
     L: the node of the "local" part of the merge (hexified version)
     O: the node of the "other" part of the merge (hexified version)
     F: a file to be merged entry
     '''
     statepathv1 = "merge/state"
     statepathv2 = "merge/state2"
 
     def __init__(self, repo):
         self._repo = repo
         self._dirty = False
         self._read()
 
     def reset(self, node=None, other=None):
         self._state = {}
         if node:
             self._local = node
             self._other = other
         shutil.rmtree(self._repo.join("merge"), True)
         self._dirty = False
 
     def _read(self):
         """Analyse each record content to restore a serialized state from disk
 
         This function process "record" entry produced by the de-serialization
         of on disk file.
         """
         self._state = {}
         records = self._readrecords()
         for rtype, record in records:
             if rtype == 'L':
                 self._local = bin(record)
             elif rtype == 'O':
                 self._other = bin(record)
             elif rtype == "F":
                 bits = record.split("\0")
                 self._state[bits[0]] = bits[1:]
             elif not rtype.islower():
                 raise util.Abort(_('unsupported merge state record: %s')
                                    % rtype)
         self._dirty = False
 
     def _readrecords(self):
         """Read merge state from disk and return a list of record (TYPE, data)
 
         We read data from both v1 and v2 files and decide which one to use.
 
         V1 has been used by version prior to 2.9.1 and contains less data than
         v2. We read both versions and check if no data in v2 contradicts
         v1. If there is not contradiction we can safely assume that both v1
         and v2 were written at the same time and use the extract data in v2. If
         there is contradiction we ignore v2 content as we assume an old version
         of Mercurial has overwritten the mergestate file and left an old v2
         file around.
 
         returns list of record [(TYPE, data), ...]"""
         v1records = self._readrecordsv1()
         v2records = self._readrecordsv2()
         oldv2 = set() # old format version of v2 record
         for rec in v2records:
             if rec[0] == 'L':
                 oldv2.add(rec)
             elif rec[0] == 'F':
                 # drop the onode data (not contained in v1)
                 oldv2.add(('F', _droponode(rec[1])))
         for rec in v1records:
             if rec not in oldv2:
                 # v1 file is newer than v2 file, use it
                 # we have to infer the "other" changeset of the merge
                 # we cannot do better than that with v1 of the format
                 mctx = self._repo[None].parents()[-1]
                 v1records.append(('O', mctx.hex()))
                 # add place holder "other" file node information
                 # nobody is using it yet so we do no need to fetch the data
                 # if mctx was wrong `mctx[bits[-2]]` may fails.
                 for idx, r in enumerate(v1records):
                     if r[0] == 'F':
                         bits = r[1].split("\0")
                         bits.insert(-2, '')
                         v1records[idx] = (r[0], "\0".join(bits))
                 return v1records
         else:
             return v2records
 
     def _readrecordsv1(self):
         """read on disk merge state for version 1 file
 
         returns list of record [(TYPE, data), ...]
 
         Note: the "F" data from this file are one entry short
               (no "other file node" entry)
         """
         records = []
         try:
             f = self._repo.opener(self.statepathv1)
             for i, l in enumerate(f):
                 if i == 0:
                     records.append(('L', l[:-1]))
                 else:
                     records.append(('F', l[:-1]))
             f.close()
         except IOError, err:
             if err.errno != errno.ENOENT:
                 raise
         return records
 
     def _readrecordsv2(self):
         """read on disk merge state for version 2 file
 
         returns list of record [(TYPE, data), ...]
         """
         records = []
         try:
             f = self._repo.opener(self.statepathv2)
             data = f.read()
             off = 0
             end = len(data)
             while off < end:
                 rtype = data[off]
                 off += 1
                 length = _unpack('>I', data[off:(off + 4)])[0]
                 off += 4
                 record = data[off:(off + length)]
                 off += length
                 records.append((rtype, record))
             f.close()
         except IOError, err:
             if err.errno != errno.ENOENT:
                 raise
         return records
 
     def commit(self):
         """Write current state on disk (if necessary)"""
         if self._dirty:
             records = []
             records.append(("L", hex(self._local)))
             records.append(("O", hex(self._other)))
             for d, v in self._state.iteritems():
                 records.append(("F", "\0".join([d] + v)))
             self._writerecords(records)
             self._dirty = False
 
     def _writerecords(self, records):
         """Write current state on disk (both v1 and v2)"""
         self._writerecordsv1(records)
         self._writerecordsv2(records)
 
     def _writerecordsv1(self, records):
         """Write current state on disk in a version 1 file"""
         f = self._repo.opener(self.statepathv1, "w")
         irecords = iter(records)
         lrecords = irecords.next()
         assert lrecords[0] == 'L'
         f.write(hex(self._local) + "\n")
         for rtype, data in irecords:
             if rtype == "F":
                 f.write("%s\n" % _droponode(data))
         f.close()
 
     def _writerecordsv2(self, records):
         """Write current state on disk in a version 2 file"""
         f = self._repo.opener(self.statepathv2, "w")
         for key, data in records:
             assert len(key) == 1
             format = ">sI%is" % len(data)
             f.write(_pack(format, key, len(data), data))
         f.close()
 
     def add(self, fcl, fco, fca, fd):
         """add a new (potentially?) conflicting file the merge state
         fcl: file context for local,
         fco: file context for remote,
         fca: file context for ancestors,
         fd:  file path of the resulting merge.
 
         note: also write the local version to the `.hg/merge` directory.
         """
         hash = util.sha1(fcl.path()).hexdigest()
         self._repo.opener.write("merge/" + hash, fcl.data())
         self._state[fd] = ['u', hash, fcl.path(),
                            fca.path(), hex(fca.filenode()),
                            fco.path(), hex(fco.filenode()),
                            fcl.flags()]
         self._dirty = True
 
     def __contains__(self, dfile):
         return dfile in self._state
 
     def __getitem__(self, dfile):
         return self._state[dfile][0]
 
     def __iter__(self):
         l = self._state.keys()
         l.sort()
         for f in l:
             yield f
 
     def files(self):
         return self._state.keys()
 
     def mark(self, dfile, state):
         self._state[dfile][0] = state
         self._dirty = True
 
     def resolve(self, dfile, wctx):
         """rerun merge process for file path `dfile`"""
         if self[dfile] == 'r':
             return 0
         stateentry = self._state[dfile]
         state, hash, lfile, afile, anode, ofile, onode, flags = stateentry
         octx = self._repo[self._other]
         fcd = wctx[dfile]
         fco = octx[ofile]
         fca = self._repo.filectx(afile, fileid=anode)
         # "premerge" x flags
         flo = fco.flags()
         fla = fca.flags()
         if 'x' in flags + flo + fla and 'l' not in flags + flo + fla:
             if fca.node() == nullid:
                 self._repo.ui.warn(_('warning: cannot merge flags for %s\n') %
                                    afile)
             elif flags == fla:
                 flags = flo
         # restore local
         f = self._repo.opener("merge/" + hash)
         self._repo.wwrite(dfile, f.read(), flags)
         f.close()
         r = filemerge.filemerge(self._repo, self._local, lfile, fcd, fco, fca)
         if r is None:
             # no real conflict
             del self._state[dfile]
             self._dirty = True
         elif not r:
             self.mark(dfile, 'r')
         return r
 
 def _checkunknownfile(repo, wctx, mctx, f):
     return (not repo.dirstate._ignore(f)
         and os.path.isfile(repo.wjoin(f))
         and repo.wopener.audit.check(f)
         and repo.dirstate.normalize(f) not in repo.dirstate
         and mctx[f].cmp(wctx[f]))
 
 def _checkunknown(repo, wctx, mctx):
     "check for collisions between unknown files and files in mctx"
 
     error = False
     for f in mctx:
         if f not in wctx and _checkunknownfile(repo, wctx, mctx, f):
             error = True
             wctx._repo.ui.warn(_("%s: untracked file differs\n") % f)
     if error:
         raise util.Abort(_("untracked files in working directory differ "
                            "from files in requested revision"))
 
 def _forgetremoved(wctx, mctx, branchmerge):
     """
     Forget removed files
 
     If we're jumping between revisions (as opposed to merging), and if
     neither the working directory nor the target rev has the file,
     then we need to remove it from the dirstate, to prevent the
     dirstate from listing the file when it is no longer in the
     manifest.
 
     If we're merging, and the other revision has removed a file
     that is not present in the working directory, we need to mark it
     as removed.
     """
 
     actions = []
     state = branchmerge and 'r' or 'f'
     for f in wctx.deleted():
         if f not in mctx:
             actions.append((f, state, None, "forget deleted"))
 
     if not branchmerge:
         for f in wctx.removed():
             if f not in mctx:
                 actions.append((f, "f", None, "forget removed"))
 
     return actions
 
 def _checkcollision(repo, wmf, actions):
     # build provisional merged manifest up
     pmmf = set(wmf)
 
     def addop(f, args):
         pmmf.add(f)
     def removeop(f, args):
         pmmf.discard(f)
     def nop(f, args):
         pass
 
     def renamemoveop(f, args):
         f2, flags = args
         pmmf.discard(f2)
         pmmf.add(f)
     def renamegetop(f, args):
         f2, flags = args
         pmmf.add(f)
     def mergeop(f, args):
         f1, f2, fa, move, anc = args
         if move:
             pmmf.discard(f1)
         pmmf.add(f)
 
     opmap = {
         "a": addop,
         "dm": renamemoveop,
         "dg": renamegetop,
         "dr": nop,
         "e": nop,
         "f": addop, # untracked file should be kept in working directory
         "g": addop,
         "m": mergeop,
         "r": removeop,
         "rd": nop,
         "cd": addop,
         "dc": addop,
     }
     for f, m, args, msg in actions:
         op = opmap.get(m)
         assert op, m
         op(f, args)
 
     # check case-folding collision in provisional merged manifest
     foldmap = {}
     for f in sorted(pmmf):
         fold = util.normcase(f)
         if fold in foldmap:
             raise util.Abort(_("case-folding collision between %s and %s")
                              % (f, foldmap[fold]))
         foldmap[fold] = f
 
 def manifestmerge(repo, wctx, p2, pa, branchmerge, force, partial,
                   acceptremote, followcopies):
     """
     Merge p1 and p2 with ancestor pa and generate merge action list
 
     branchmerge and force are as passed in to update
     partial = function to filter file lists
     acceptremote = accept the incoming changes without prompting
     """
 
     actions, copy, movewithdir = [], {}, {}
 
     # manifests fetched in order are going to be faster, so prime the caches
     [x.manifest() for x in
      sorted(wctx.parents() + [p2, pa], key=lambda x: x.rev())]
 
     if followcopies:
         ret = copies.mergecopies(repo, wctx, p2, pa)
         copy, movewithdir, diverge, renamedelete = ret
         for of, fl in diverge.iteritems():
             actions.append((of, "dr", (fl,), "divergent renames"))
         for of, fl in renamedelete.iteritems():
             actions.append((of, "rd", (fl,), "rename and delete"))
 
     repo.ui.note(_("resolving manifests\n"))
     repo.ui.debug(" branchmerge: %s, force: %s, partial: %s\n"
                   % (bool(branchmerge), bool(force), bool(partial)))
     repo.ui.debug(" ancestor: %s, local: %s, remote: %s\n" % (pa, wctx, p2))
 
     m1, m2, ma = wctx.manifest(), p2.manifest(), pa.manifest()
     copied = set(copy.values())
     copied.update(movewithdir.values())
 
     if '.hgsubstate' in m1:
         # check whether sub state is modified
         for s in sorted(wctx.substate):
             if wctx.sub(s).dirty():
                 m1['.hgsubstate'] += "+"
                 break
 
     aborts = []
     # Compare manifests
     fdiff = dicthelpers.diff(m1, m2)
     flagsdiff = m1.flagsdiff(m2)
     diff12 = dicthelpers.join(fdiff, flagsdiff)
 
     for f, (n12, fl12) in diff12.iteritems():
         if n12:
             n1, n2 = n12
         else: # file contents didn't change, but flags did
             n1 = n2 = m1.get(f, None)
             if n1 is None:
                 # Since n1 == n2, the file isn't present in m2 either. This
                 # means that the file was removed or deleted locally and
                 # removed remotely, but that residual entries remain in flags.
                 # This can happen in manifests generated by workingctx.
                 continue
         if fl12:
             fl1, fl2 = fl12
         else: # flags didn't change, file contents did
             fl1 = fl2 = m1.flags(f)
 
         if partial and not partial(f):
             continue
         if n1 and n2:
             fa = f
             a = ma.get(f, nullid)
             if a == nullid:
                 fa = copy.get(f, f)
                 # Note: f as default is wrong - we can't really make a 3-way
                 # merge without an ancestor file.
             fla = ma.flags(fa)
             nol = 'l' not in fl1 + fl2 + fla
             if n2 == a and fl2 == fla:
                 pass # remote unchanged - keep local
             elif n1 == a and fl1 == fla: # local unchanged - use remote
                 if n1 == n2: # optimization: keep local content
                     actions.append((f, "e", (fl2,), "update permissions"))
                 else:
                     actions.append((f, "g", (fl2,), "remote is newer"))
             elif nol and n2 == a: # remote only changed 'x'
                 actions.append((f, "e", (fl2,), "update permissions"))
             elif nol and n1 == a: # local only changed 'x'
                 actions.append((f, "g", (fl1,), "remote is newer"))
             else: # both changed something
                 actions.append((f, "m", (f, f, fa, False, pa.node()),
                                "versions differ"))
         elif f in copied: # files we'll deal with on m2 side
             pass
         elif n1 and f in movewithdir: # directory rename, move local
             f2 = movewithdir[f]
             actions.append((f2, "dm", (f, fl1),
                             "remote directory rename - move from " + f))
         elif n1 and f in copy:
             f2 = copy[f]
             actions.append((f, "m", (f, f2, f2, False, pa.node()),
                             "local copied/moved from " + f2))
         elif n1 and f in ma: # clean, a different, no remote
             if n1 != ma[f]:
                 if acceptremote:
                     actions.append((f, "r", None, "remote delete"))
                 else:
                     actions.append((f, "cd", None, "prompt changed/deleted"))
             elif n1[20:] == "a": # added, no remote
                 actions.append((f, "f", None, "remote deleted"))
             else:
                 actions.append((f, "r", None, "other deleted"))
         elif n2 and f in movewithdir:
             f2 = movewithdir[f]
             actions.append((f2, "dg", (f, fl2),
                             "local directory rename - get from " + f))
         elif n2 and f in copy:
             f2 = copy[f]
             if f2 in m2:
                 actions.append((f, "m", (f2, f, f2, False, pa.node()),
                                 "remote copied from " + f2))
             else:
                 actions.append((f, "m", (f2, f, f2, True, pa.node()),
                                 "remote moved from " + f2))
         elif n2 and f not in ma:
             # local unknown, remote created: the logic is described by the
             # following table:
             #
             # force  branchmerge  different  |  action
             #   n         *           n      |    get
             #   n         *           y      |   abort
             #   y         n           *      |    get
             #   y         y           n      |    get
             #   y         y           y      |   merge
             #
             # Checking whether the files are different is expensive, so we
             # don't do that when we can avoid it.
             if force and not branchmerge:
                 actions.append((f, "g", (fl2,), "remote created"))
             else:
                 different = _checkunknownfile(repo, wctx, p2, f)
                 if force and branchmerge and different:
                     # FIXME: This is wrong - f is not in ma ...
                     actions.append((f, "m", (f, f, f, False, pa.node()),
                                     "remote differs from untracked local"))
                 elif not force and different:
                     aborts.append((f, "ud"))
                 else:
                     actions.append((f, "g", (fl2,), "remote created"))
         elif n2 and n2 != ma[f]:
             different = _checkunknownfile(repo, wctx, p2, f)
             if not force and different:
                 aborts.append((f, "ud"))
             else:
                 # if different: old untracked f may be overwritten and lost
                 if acceptremote:
                     actions.append((f, "g", (m2.flags(f),),
                                    "remote recreating"))
                 else:
                     actions.append((f, "dc", (m2.flags(f),),
                                    "prompt deleted/changed"))
 
     for f, m in sorted(aborts):
         if m == "ud":
             repo.ui.warn(_("%s: untracked file differs\n") % f)
         else: assert False, m
     if aborts:
         raise util.Abort(_("untracked files in working directory differ "
                            "from files in requested revision"))
 
     if not util.checkcase(repo.path):
         # check collision between files only in p2 for clean update
         if (not branchmerge and
             (force or not wctx.dirty(missing=True, branch=False))):
             _checkcollision(repo, m2, [])
         else:
             _checkcollision(repo, m1, actions)
 
     return actions
 
 def actionkey(a):
     return a[1] in "rf" and -1 or 0, a
 
 def getremove(repo, mctx, overwrite, args):
     """apply usually-non-interactive updates to the working directory
 
     mctx is the context to be merged into the working copy
 
     yields tuples for progress updates
     """
     verbose = repo.ui.verbose
     unlink = util.unlinkpath
     wjoin = repo.wjoin
     fctx = mctx.filectx
     wwrite = repo.wwrite
     audit = repo.wopener.audit
     i = 0
     for arg in args:
         f = arg[0]
         if arg[1] == 'r':
             if verbose:
                 repo.ui.note(_("removing %s\n") % f)
             audit(f)
             try:
                 unlink(wjoin(f), ignoremissing=True)
             except OSError, inst:
                 repo.ui.warn(_("update failed to remove %s: %s!\n") %
                              (f, inst.strerror))
         else:
             if verbose:
                 repo.ui.note(_("getting %s\n") % f)
             wwrite(f, fctx(f).data(), arg[2][0])
         if i == 100:
             yield i, f
             i = 0
         i += 1
     if i > 0:
         yield i, f
 
 def applyupdates(repo, actions, wctx, mctx, overwrite):
     """apply the merge action list to the working directory
 
     wctx is the working copy context
     mctx is the context to be merged into the working copy
 
     Return a tuple of counts (updated, merged, removed, unresolved) that
     describes how many files were affected by the update.
     """
 
     updated, merged, removed, unresolved = 0, 0, 0, 0
     ms = mergestate(repo)
     ms.reset(wctx.p1().node(), mctx.node())
     moves = []
     actions.sort(key=actionkey)
 
     # prescan for merges
     for a in actions:
         f, m, args, msg = a
         repo.ui.debug(" %s: %s -> %s\n" % (f, msg, m))
         if m == "m": # merge
             f1, f2, fa, move, anc = args
             if f == '.hgsubstate': # merged internally
                 continue
             repo.ui.debug("  preserving %s for resolve of %s\n" % (f1, f))
             fcl = wctx[f1]
             fco = mctx[f2]
             actx = repo[anc]
             if fa in actx:
                 fca = actx[fa]
             else:
                 fca = repo.filectx(f1, fileid=nullrev)
             ms.add(fcl, fco, fca, f)
             if f1 != f and move:
                 moves.append(f1)
 
     audit = repo.wopener.audit
 
     # remove renamed files after safely stored
     for f in moves:
         if os.path.lexists(repo.wjoin(f)):
             repo.ui.debug("removing %s\n" % f)
             audit(f)
             util.unlinkpath(repo.wjoin(f))
 
     numupdates = len(actions)
     workeractions = [a for a in actions if a[1] in 'gr']
     updateactions = [a for a in workeractions if a[1] == 'g']
     updated = len(updateactions)
     removeactions = [a for a in workeractions if a[1] == 'r']
     removed = len(removeactions)
     actions = [a for a in actions if a[1] not in 'gr']
 
     hgsub = [a[1] for a in workeractions if a[0] == '.hgsubstate']
     if hgsub and hgsub[0] == 'r':
         subrepo.submerge(repo, wctx, mctx, wctx, overwrite)
 
     z = 0
     prog = worker.worker(repo.ui, 0.001, getremove, (repo, mctx, overwrite),
                          removeactions)
     for i, item in prog:
         z += i
         repo.ui.progress(_('updating'), z, item=item, total=numupdates,
                          unit=_('files'))
     prog = worker.worker(repo.ui, 0.001, getremove, (repo, mctx, overwrite),
                          updateactions)
     for i, item in prog:
         z += i
         repo.ui.progress(_('updating'), z, item=item, total=numupdates,
                          unit=_('files'))
 
     if hgsub and hgsub[0] == 'g':
         subrepo.submerge(repo, wctx, mctx, wctx, overwrite)
 
     _updating = _('updating')
     _files = _('files')
     progress = repo.ui.progress
 
     for i, a in enumerate(actions):
         f, m, args, msg = a
         progress(_updating, z + i + 1, item=f, total=numupdates, unit=_files)
         if m == "m": # merge
             f1, f2, fa, move, anc = args
             if f == '.hgsubstate': # subrepo states need updating
                 subrepo.submerge(repo, wctx, mctx, wctx.ancestor(mctx),
                                  overwrite)
                 continue
             audit(f)
             r = ms.resolve(f, wctx)
             if r is not None and r > 0:
                 unresolved += 1
             else:
                 if r is None:
                     updated += 1
                 else:
                     merged += 1
         elif m == "dm": # directory rename, move local
             f0, flags = args
             repo.ui.note(_("moving %s to %s\n") % (f0, f))
             audit(f)
             repo.wwrite(f, wctx.filectx(f0).data(), flags)
             util.unlinkpath(repo.wjoin(f0))
             updated += 1
         elif m == "dg": # local directory rename, get
             f0, flags = args
             repo.ui.note(_("getting %s to %s\n") % (f0, f))
             repo.wwrite(f, mctx.filectx(f0).data(), flags)
             updated += 1
         elif m == "dr": # divergent renames
             fl, = args
             repo.ui.warn(_("note: possible conflict - %s was renamed "
                            "multiple times to:\n") % f)
             for nf in fl:
                 repo.ui.warn(" %s\n" % nf)
         elif m == "rd": # rename and delete
             fl, = args
             repo.ui.warn(_("note: possible conflict - %s was deleted "
                            "and renamed to:\n") % f)
             for nf in fl:
                 repo.ui.warn(" %s\n" % nf)
         elif m == "e": # exec
             flags, = args
             audit(f)
             util.setflags(repo.wjoin(f), 'l' in flags, 'x' in flags)
             updated += 1
     ms.commit()
     progress(_updating, None, total=numupdates, unit=_files)
 
     return updated, merged, removed, unresolved
 
-def calculateupdates(repo, wctx, mctx, ancestor, branchmerge, force, partial,
+def calculateupdates(repo, wctx, mctx, ancestors, branchmerge, force, partial,
                      acceptremote, followcopies):
-    "Calculate the actions needed to merge mctx into wctx using ancestor"
+    "Calculate the actions needed to merge mctx into wctx using ancestors"
+
+    ancestor = ancestors[0]
 
     actions = manifestmerge(repo, wctx, mctx,
                              ancestor,
                              branchmerge, force,
                              partial, acceptremote, followcopies)
 
     # Filter out prompts.
     newactions, prompts = [], []
     for a in actions:
         if a[1] in ("cd", "dc"):
             prompts.append(a)
         else:
             newactions.append(a)
     # Prompt and create actions. TODO: Move this towards resolve phase.
     for f, m, args, msg in sorted(prompts):
         if m == "cd":
             if repo.ui.promptchoice(
                 _("local changed %s which remote deleted\n"
                   "use (c)hanged version or (d)elete?"
                   "$$ &Changed $$ &Delete") % f, 0):
                 newactions.append((f, "r", None, "prompt delete"))
             else:
                 newactions.append((f, "a", None, "prompt keep"))
         elif m == "dc":
             flags, = args
             if repo.ui.promptchoice(
                 _("remote changed %s which local deleted\n"
                   "use (c)hanged version or leave (d)eleted?"
                   "$$ &Changed $$ &Deleted") % f, 0) == 0:
                 newactions.append((f, "g", (flags,), "prompt recreating"))
         else: assert False, m
 
     if wctx.rev() is None:
         newactions += _forgetremoved(wctx, mctx, branchmerge)
 
     return newactions
 
 def recordupdates(repo, actions, branchmerge):
     "record merge actions to the dirstate"
 
     for a in actions:
         f, m, args, msg = a
         if m == "r": # remove
             if branchmerge:
                 repo.dirstate.remove(f)
             else:
                 repo.dirstate.drop(f)
         elif m == "a": # re-add
             if not branchmerge:
                 repo.dirstate.add(f)
         elif m == "f": # forget
             repo.dirstate.drop(f)
         elif m == "e": # exec change
             repo.dirstate.normallookup(f)
         elif m == "g": # get
             if branchmerge:
                 repo.dirstate.otherparent(f)
             else:
                 repo.dirstate.normal(f)
         elif m == "m": # merge
             f1, f2, fa, move, anc = args
             if branchmerge:
                 # We've done a branch merge, mark this file as merged
                 # so that we properly record the merger later
                 repo.dirstate.merge(f)
                 if f1 != f2: # copy/rename
                     if move:
                         repo.dirstate.remove(f1)
                     if f1 != f:
                         repo.dirstate.copy(f1, f)
                     else:
                         repo.dirstate.copy(f2, f)
             else:
                 # We've update-merged a locally modified file, so
                 # we set the dirstate to emulate a normal checkout
                 # of that file some time in the past. Thus our
                 # merge will appear as a normal local file
                 # modification.
                 if f2 == f: # file not locally copied/moved
                     repo.dirstate.normallookup(f)
                 if move:
                     repo.dirstate.drop(f1)
         elif m == "dm": # directory rename, move local
             f0, flag = args
             if f0 not in repo.dirstate:
                 # untracked file moved
                 continue
             if branchmerge:
                 repo.dirstate.add(f)
                 repo.dirstate.remove(f0)
                 repo.dirstate.copy(f0, f)
             else:
                 repo.dirstate.normal(f)
                 repo.dirstate.drop(f0)
         elif m == "dg": # directory rename, get
             f0, flag = args
             if branchmerge:
                 repo.dirstate.add(f)
                 repo.dirstate.copy(f0, f)
             else:
                 repo.dirstate.normal(f)
 
 def update(repo, node, branchmerge, force, partial, ancestor=None,
            mergeancestor=False):
     """
     Perform a merge between the working directory and the given node
 
     node = the node to update to, or None if unspecified
     branchmerge = whether to merge between branches
     force = whether to force branch merging or file overwriting
     partial = a function to filter file lists (dirstate not updated)
     mergeancestor = whether it is merging with an ancestor. If true,
       we should accept the incoming changes for any prompts that occur.
       If false, merging with an ancestor (fast-forward) is only allowed
       between different named branches. This flag is used by rebase extension
       as a temporary fix and should be avoided in general.
 
     The table below shows all the behaviors of the update command
     given the -c and -C or no options, whether the working directory
     is dirty, whether a revision is specified, and the relationship of
     the parent rev to the target rev (linear, on the same named
     branch, or on another named branch).
 
     This logic is tested by test-update-branches.t.
 
     -c  -C  dirty  rev  |  linear   same  cross
      n   n    n     n   |    ok     (1)     x
      n   n    n     y   |    ok     ok     ok
      n   n    y     n   |   merge   (2)    (2)
      n   n    y     y   |   merge   (3)    (3)
      n   y    *     *   |    ---  discard  ---
      y   n    y     *   |    ---    (4)    ---
      y   n    n     *   |    ---    ok     ---
      y   y    *     *   |    ---    (5)    ---
 
     x = can't happen
     * = don't-care
     1 = abort: not a linear update (merge or update --check to force update)
     2 = abort: uncommitted changes (commit and merge, or update --clean to
                  discard changes)
     3 = abort: uncommitted changes (commit or update --clean to discard changes)
     4 = abort: uncommitted changes (checked in commands.py)
     5 = incompatible options (checked in commands.py)
 
     Return the same tuple as applyupdates().
     """
 
     onode = node
     wlock = repo.wlock()
     try:
         wc = repo[None]
         pl = wc.parents()
         p1 = pl[0]
-        pa = None
+        pas = [None]
         if ancestor:
-            pa = repo[ancestor]
+            pas = [repo[ancestor]]
 
         if node is None:
             # Here is where we should consider bookmarks, divergent bookmarks,
             # foreground changesets (successors), and tip of current branch;
             # but currently we are only checking the branch tips.
             try:
                 node = repo.branchtip(wc.branch())
             except error.RepoLookupError:
                 if wc.branch() == "default": # no default branch!
                     node = repo.lookup("tip") # update to tip
                 else:
                     raise util.Abort(_("branch %s not found") % wc.branch())
 
             if p1.obsolete() and not p1.children():
                 # allow updating to successors
                 successors = obsolete.successorssets(repo, p1.node())
 
                 # behavior of certain cases is as follows,
                 #
                 # divergent changesets: update to highest rev, similar to what
                 #     is currently done when there are more than one head
                 #     (i.e. 'tip')
                 #
                 # replaced changesets: same as divergent except we know there
                 # is no conflict
                 #
                 # pruned changeset: no update is done; though, we could
                 #     consider updating to the first non-obsolete parent,
                 #     similar to what is current done for 'hg prune'
 
                 if successors:
                     # flatten the list here handles both divergent (len > 1)
                     # and the usual case (len = 1)
                     successors = [n for sub in successors for n in sub]
 
                     # get the max revision for the given successors set,
                     # i.e. the 'tip' of a set
                     node = repo.revs("max(%ln)", successors)[0]
-                    pa = p1
+                    pas = [p1]
 
         overwrite = force and not branchmerge
 
         p2 = repo[node]
-        if pa is None:
-            pa = p1.ancestor(p2)
+        if pas[0] is None:
+            pas = [p1.ancestor(p2)]
 
         fp1, fp2, xp1, xp2 = p1.node(), p2.node(), str(p1), str(p2)
 
         ### check phase
         if not overwrite and len(pl) > 1:
             raise util.Abort(_("outstanding uncommitted merges"))
         if branchmerge:
-            if pa == p2:
+            if pas == [p2]:
                 raise util.Abort(_("merging with a working directory ancestor"
                                    " has no effect"))
-            elif pa == p1:
+            elif pas == [p1]:
                 if not mergeancestor and p1.branch() == p2.branch():
                     raise util.Abort(_("nothing to merge"),
                                      hint=_("use 'hg update' "
                                             "or check 'hg heads'"))
             if not force and (wc.files() or wc.deleted()):
                 raise util.Abort(_("uncommitted changes"),
                                  hint=_("use 'hg status' to list changes"))
             for s in sorted(wc.substate):
                 if wc.sub(s).dirty():
                     raise util.Abort(_("uncommitted changes in "
                                        "subrepository '%s'") % s)
 
         elif not overwrite:
             if p1 == p2: # no-op update
                 # call the hooks and exit early
                 repo.hook('preupdate', throw=True, parent1=xp2, parent2='')
                 repo.hook('update', parent1=xp2, parent2='', error=0)
                 return 0, 0, 0, 0
 
-            if pa not in (p1, p2):  # nonlinear
+            if pas not in ([p1], [p2]):  # nonlinear
                 dirty = wc.dirty(missing=True)
                 if dirty or onode is None:
                     # Branching is a bit strange to ensure we do the minimal
                     # amount of call to obsolete.background.
                     foreground = obsolete.foreground(repo, [p1.node()])
                     # note: the <node> variable contains a random identifier
                     if repo[node].node() in foreground:
-                        pa = p1  # allow updating to successors
+                        pas = [p1]  # allow updating to successors
                     elif dirty:
                         msg = _("uncommitted changes")
                         if onode is None:
                             hint = _("commit and merge, or update --clean to"
                                      " discard changes")
                         else:
                             hint = _("commit or update --clean to discard"
                                      " changes")
                         raise util.Abort(msg, hint=hint)
                     else:  # node is none
                         msg = _("not a linear update")
                         hint = _("merge or update --check to force update")
                         raise util.Abort(msg, hint=hint)
                 else:
                     # Allow jumping branches if clean and specific rev given
-                    pa = p1
+                    pas = [p1]
 
         followcopies = False
         if overwrite:
-            pa = wc
-        elif pa == p2: # backwards
-            pa = wc.p1()
+            pas = [wc]
+        elif pas == [p2]: # backwards
+            pas = [wc.p1()]
         elif not branchmerge and not wc.dirty(missing=True):
             pass
-        elif pa and repo.ui.configbool("merge", "followcopies", True):
+        elif pas[0] and repo.ui.configbool("merge", "followcopies", True):
             followcopies = True
 
         ### calculate phase
-        actions = calculateupdates(repo, wc, p2, pa, branchmerge, force,
+        actions = calculateupdates(repo, wc, p2, pas, branchmerge, force,
                                    partial, mergeancestor, followcopies)
 
         ### apply phase
         if not branchmerge: # just jump to the new rev
             fp1, fp2, xp1, xp2 = fp2, nullid, xp2, ''
         if not partial:
             repo.hook('preupdate', throw=True, parent1=xp1, parent2=xp2)
             # note that we're in the middle of an update
             repo.vfs.write('updatestate', p2.hex())
 
         stats = applyupdates(repo, actions, wc, p2, overwrite)
 
         if not partial:
             repo.setparents(fp1, fp2)
             recordupdates(repo, actions, branchmerge)
             # update completed, clear state
             util.unlink(repo.join('updatestate'))
 
             if not branchmerge:
                 repo.dirstate.setbranch(p2.branch())
     finally:
         wlock.release()
 
     if not partial:
         repo.hook('update', parent1=xp1, parent2=xp2, error=stats[3])
     return stats