manifestmerge: local unknown, remote created: don't traverse symlinks

To figure out what to do with locally unknown files, Mercurial attempts to read
them if they exist. When an attempt is made to read a file that exists but
traverses a symlink, Mercurial aborts.

With this patch, we first ensure that the file doesn't traverse a symlink
before opening it. This is fine because a file being "remote created" means the
symlink doesn't exist remotely, which means it will be deleted in the apply
phase.

mercurial/merge.py

@@ -1,760 +1,761 b''
 # 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.
 
 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
 
 class mergestate(object):
     '''track 3-way merge state of individual files'''
     def __init__(self, repo):
         self._repo = repo
         self._dirty = False
         self._read()
     def reset(self, node=None):
         self._state = {}
         if node:
             self._local = node
         shutil.rmtree(self._repo.join("merge"), True)
         self._dirty = False
     def _read(self):
         self._state = {}
         try:
             f = self._repo.opener("merge/state")
             for i, l in enumerate(f):
                 if i == 0:
                     self._local = bin(l[:-1])
                 else:
                     bits = l[:-1].split("\0")
                     self._state[bits[0]] = bits[1:]
             f.close()
         except IOError, err:
             if err.errno != errno.ENOENT:
                 raise
         self._dirty = False
     def commit(self):
         if self._dirty:
             f = self._repo.opener("merge/state", "w")
             f.write(hex(self._local) + "\n")
             for d, v in self._state.iteritems():
                 f.write("\0".join([d] + v) + "\n")
             f.close()
             self._dirty = False
     def add(self, fcl, fco, fca, fd):
         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(), 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 mark(self, dfile, state):
         self._state[dfile][0] = state
         self._dirty = True
     def resolve(self, dfile, wctx, octx):
         if self[dfile] == 'r':
             return 0
         state, hash, lfile, afile, anode, ofile, flags = self._state[dfile]
         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]
         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, prompts):
     # 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 renameop(f, args):
         f2, fd, flags = args
         if f:
             pmmf.discard(f)
         pmmf.add(fd)
     def mergeop(f, args):
         f2, fd, move = args
         if move:
             pmmf.discard(f)
         pmmf.add(fd)
 
     opmap = {
         "a": addop,
         "d": renameop,
         "dr": nop,
         "e": nop,
         "f": addop, # untracked file should be kept in working directory
         "g": addop,
         "m": mergeop,
         "r": removeop,
         "rd": nop,
     }
     for f, m, args, msg in actions:
         op = opmap.get(m)
         assert op, m
         op(f, args)
 
     opmap = {
         "cd": addop,
         "dc": addop,
     }
     for f, m in prompts:
         op = opmap.get(m)
         assert op, m
         op(f, None)
 
     # 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=False):
     """
     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
     """
 
     overwrite = force and not branchmerge
     actions, copy, movewithdir = [], {}, {}
 
     followcopies = False
     if overwrite:
         pa = wctx
     elif pa == p2: # backwards
         pa = wctx.p1()
     elif not branchmerge and not wctx.dirty(missing=True):
         pass
     elif pa and repo.ui.configbool("merge", "followcopies", True):
         followcopies = True
 
     # 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, prompts = [], []
     # 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:
             fla = ma.flags(f)
             nol = 'l' not in fl1 + fl2 + fla
             a = ma.get(f, nullid)
             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, False), "versions differ"))
         elif f in copied: # files we'll deal with on m2 side
             pass
         elif n1 and f in movewithdir: # directory rename
             f2 = movewithdir[f]
             actions.append((f, "d", (None, f2, fl1),
                             "remote renamed directory to " + f2))
         elif n1 and f in copy:
             f2 = copy[f]
             actions.append((f, "m", (f2, f, False),
                             "local copied/moved to " + f2))
         elif n1 and f in ma: # clean, a different, no remote
             if n1 != ma[f]:
                 prompts.append((f, "cd")) # 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((None, "d", (f, f2, fl2),
                             "local renamed directory to " + f2))
         elif n2 and f in copy:
             f2 = copy[f]
             if f2 in m2:
                 actions.append((f2, "m", (f, f, False),
                                 "remote copied to " + f))
             else:
                 actions.append((f2, "m", (f, f, True),
                                 "remote moved to " + f))
         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:
                     actions.append((f, "m", (f, f, False),
                                     "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]:
             prompts.append((f, "dc")) # 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, prompts)
 
     for f, m in sorted(prompts):
         if m == "cd":
             if acceptremote:
                 actions.append((f, "r", None, "remote delete"))
             elif repo.ui.promptchoice(
                 _("local changed %s which remote deleted\n"
                   "use (c)hanged version or (d)elete?") % f,
                 (_("&Changed"), _("&Delete")), 0):
                 actions.append((f, "r", None, "prompt delete"))
             else:
                 actions.append((f, "a", None, "prompt keep"))
         elif m == "dc":
             if acceptremote:
                 actions.append((f, "g", (m2.flags(f),), "remote recreating"))
             elif repo.ui.promptchoice(
                 _("remote changed %s which local deleted\n"
                   "use (c)hanged version or leave (d)eleted?") % f,
                 (_("&Changed"), _("&Deleted")), 0) == 0:
                 actions.append((f, "g", (m2.flags(f),), "prompt recreating"))
         else: assert False, m
     return actions
 
 def actionkey(a):
     return a[1] == "r" 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, actx, 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
     actx is the context of the common ancestor
 
     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())
     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
             f2, fd, move = args
             if fd == '.hgsubstate': # merged internally
                 continue
             repo.ui.debug("  preserving %s for resolve of %s\n" % (f, fd))
             fcl = wctx[f]
             fco = mctx[f2]
             if mctx == actx: # backwards, use working dir parent as ancestor
                 if fcl.parents():
                     fca = fcl.p1()
                 else:
                     fca = repo.filectx(f, fileid=nullrev)
             else:
                 fca = fcl.ancestor(fco, actx)
             if not fca:
                 fca = repo.filectx(f, fileid=nullrev)
             ms.add(fcl, fco, fca, fd)
             if f != fd and move:
                 moves.append(f)
 
     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
             f2, fd, move = args
             if fd == '.hgsubstate': # subrepo states need updating
                 subrepo.submerge(repo, wctx, mctx, wctx.ancestor(mctx),
                                  overwrite)
                 continue
             audit(fd)
             r = ms.resolve(fd, wctx, mctx)
             if r is not None and r > 0:
                 unresolved += 1
             else:
                 if r is None:
                     updated += 1
                 else:
                     merged += 1
         elif m == "d": # directory rename
             f2, fd, flags = args
             if f:
                 repo.ui.note(_("moving %s to %s\n") % (f, fd))
                 audit(f)
                 repo.wwrite(fd, wctx.filectx(f).data(), flags)
                 util.unlinkpath(repo.wjoin(f))
             if f2:
                 repo.ui.note(_("getting %s to %s\n") % (f2, fd))
                 repo.wwrite(fd, mctx.filectx(f2).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, tctx, mctx, ancestor, branchmerge, force, partial,
                      acceptremote=False):
     "Calculate the actions needed to merge mctx into tctx"
     actions = []
     actions += manifestmerge(repo, tctx, mctx,
                              ancestor,
                              branchmerge, force,
                              partial, acceptremote)
     if tctx.rev() is None:
         actions += _forgetremoved(tctx, mctx, branchmerge)
     return actions
 
 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
             f2, fd, move = 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(fd)
                 if f != f2: # copy/rename
                     if move:
                         repo.dirstate.remove(f)
                     if f != fd:
                         repo.dirstate.copy(f, fd)
                     else:
                         repo.dirstate.copy(f2, fd)
             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 == fd: # file not locally copied/moved
                     repo.dirstate.normallookup(fd)
                 if move:
                     repo.dirstate.drop(f)
         elif m == "d": # directory rename
             f2, fd, flag = args
             if not f2 and f not in repo.dirstate:
                 # untracked file moved
                 continue
             if branchmerge:
                 repo.dirstate.add(fd)
                 if f:
                     repo.dirstate.remove(f)
                     repo.dirstate.copy(f, fd)
                 if f2:
                     repo.dirstate.copy(f2, fd)
             else:
                 repo.dirstate.normal(fd)
                 if f:
                     repo.dirstate.drop(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     *   |   merge   (2)    (2)
      n   y    *     *   |    ---  discard  ---
      y   n    y     *   |    ---    (3)    ---
      y   n    n     *   |    ---    ok     ---
      y   y    *     *   |    ---    (4)    ---
 
     x = can't happen
     * = don't-care
     1 = abort: crosses branches (use 'hg merge' or 'hg update -c')
     2 = abort: crosses branches (use 'hg merge' to merge or
                  use 'hg update -C' to discard changes)
     3 = abort: uncommitted local changes
     4 = incompatible options (checked in commands.py)
 
     Return the same tuple as applyupdates().
     """
 
     onode = node
     wlock = repo.wlock()
     try:
         wc = repo[None]
         if node is None:
             # tip of current branch
             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())
         overwrite = force and not branchmerge
         pl = wc.parents()
         p1, p2 = pl[0], repo[node]
         if ancestor:
             pa = repo[ancestor]
         else:
             pa = 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:
                 raise util.Abort(_("merging with a working directory ancestor"
                                    " has no effect"))
             elif pa == 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(_("outstanding uncommitted changes"),
                                  hint=_("use 'hg status' to list changes"))
             for s in sorted(wc.substate):
                 if wc.sub(s).dirty():
                     raise util.Abort(_("outstanding uncommitted changes in "
                                        "subrepository '%s'") % s)
 
         elif not overwrite:
             if pa not in (p1, p2):  # nolinear
                 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
                     elif dirty:
                         msg = _("crosses branches (merge branches or use"
                                 " --clean to discard changes)")
                         raise util.Abort(msg)
                     else:  # node is none
                         msg = _("crosses branches (merge branches or update"
                                 " --check to force update)")
                         raise util.Abort(msg)
                 else:
                     # Allow jumping branches if clean and specific rev given
                     pa = p1
 
         ### calculate phase
         actions = calculateupdates(repo, wc, p2, pa,
                                    branchmerge, force, partial, mergeancestor)
 
         ### 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)
 
         stats = applyupdates(repo, actions, wc, p2, pa, overwrite)
 
         if not partial:
             repo.setparents(fp1, fp2)
             recordupdates(repo, actions, branchmerge)
             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

tests/test-symlinks.t

@@ -1,260 +1,269 b''
   $ "$TESTDIR/hghave" symlink || exit 80
 
 == tests added in 0.7 ==
 
   $ hg init test-symlinks-0.7; cd test-symlinks-0.7;
   $ touch foo; ln -s foo bar;
 
 import with addremove -- symlink walking should _not_ screwup.
 
   $ hg addremove
   adding bar
   adding foo
 
 commit -- the symlink should _not_ appear added to dir state
 
   $ hg commit -m 'initial'
 
   $ touch bomb
 
 again, symlink should _not_ show up on dir state
 
   $ hg addremove
   adding bomb
 
 Assert screamed here before, should go by without consequence
 
   $ hg commit -m 'is there a bug?'
   $ cd ..
 
 
 == fifo & ignore ==
 
   $ hg init test; cd test;
 
   $ mkdir dir
   $ touch a.c dir/a.o dir/b.o
 
 test what happens if we want to trick hg
 
   $ hg commit -A -m 0
   adding a.c
   adding dir/a.o
   adding dir/b.o
   $ echo "relglob:*.o" > .hgignore
   $ rm a.c
   $ rm dir/a.o
   $ rm dir/b.o
   $ mkdir dir/a.o
   $ ln -s nonexistent dir/b.o
   $ mkfifo a.c
 
 it should show a.c, dir/a.o and dir/b.o deleted
 
   $ hg status
   M dir/b.o
   ! a.c
   ! dir/a.o
   ? .hgignore
   $ hg status a.c
   a.c: unsupported file type (type is fifo)
   ! a.c
   $ cd ..
 
 
 == symlinks from outside the tree ==
 
 test absolute path through symlink outside repo
 
   $ p=`pwd`
   $ hg init x
   $ ln -s x y
   $ cd x
   $ touch f
   $ hg add f
   $ hg status "$p"/y/f
   A f
 
 try symlink outside repo to file inside
 
   $ ln -s x/f ../z
 
 this should fail
 
   $ hg status ../z && { echo hg mistakenly exited with status 0; exit 1; } || :
   abort: ../z not under root '$TESTTMP/x'
   $ cd ..
 
 
 == cloning symlinks ==
   $ hg init clone; cd clone;
 
 try cloning symlink in a subdir
 1. commit a symlink
 
   $ mkdir -p a/b/c
   $ cd a/b/c
   $ ln -s /path/to/symlink/source demo
   $ cd ../../..
   $ hg stat
   ? a/b/c/demo
   $ hg commit -A -m 'add symlink in a/b/c subdir'
   adding a/b/c/demo
 
 2. clone it
 
   $ cd ..
   $ hg clone clone clonedest
   updating to branch default
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
 
 
 == symlink and git diffs ==
 
 git symlink diff
 
   $ cd clonedest
   $ hg diff --git -r null:tip
   diff --git a/a/b/c/demo b/a/b/c/demo
   new file mode 120000
   --- /dev/null
   +++ b/a/b/c/demo
   @@ -0,0 +1,1 @@
   +/path/to/symlink/source
   \ No newline at end of file
   $ hg export --git tip > ../sl.diff
 
 import git symlink diff
 
   $ hg rm a/b/c/demo
   $ hg commit -m'remove link'
   $ hg import ../sl.diff
   applying ../sl.diff
   $ hg diff --git -r 1:tip
   diff --git a/a/b/c/demo b/a/b/c/demo
   new file mode 120000
   --- /dev/null
   +++ b/a/b/c/demo
   @@ -0,0 +1,1 @@
   +/path/to/symlink/source
   \ No newline at end of file
 
 == symlinks and addremove ==
 
 directory moved and symlinked
 
   $ mkdir foo
   $ touch foo/a
   $ hg ci -Ama
   adding foo/a
   $ mv foo bar
   $ ln -s bar foo
   $ hg status
   ! foo/a
   ? bar/a
   ? foo
 
 now addremove should remove old files
 
   $ hg addremove
   adding bar/a
   adding foo
   removing foo/a
+
+commit and update back
+
+  $ hg ci -mb
+  $ hg up '.^'
+  1 files updated, 0 files merged, 2 files removed, 0 files unresolved
+  $ hg up tip
+  2 files updated, 0 files merged, 1 files removed, 0 files unresolved
+
   $ cd ..
 
 == root of repository is symlinked ==
 
   $ hg init root
   $ ln -s root link
   $ cd root
   $ echo foo > foo
   $ hg status
   ? foo
   $ hg status ../link
   ? foo
   $ hg add foo
   $ hg cp foo "$TESTTMP/link/bar"
   foo has not been committed yet, so no copy data will be stored for bar.
   $ cd ..
 
 
   $ hg init b
   $ cd b
   $ ln -s nothing dangling
   $ hg commit -m 'commit symlink without adding' dangling
   abort: dangling: file not tracked!
   [255]
   $ hg add dangling
   $ hg commit -m 'add symlink'
 
   $ hg tip -v
   changeset:   0:cabd88b706fc
   tag:         tip
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   files:       dangling
   description:
   add symlink
   
   
   $ hg manifest --debug
   2564acbe54bbbedfbf608479340b359f04597f80 644 @ dangling
   $ "$TESTDIR/readlink.py" dangling
   dangling -> nothing
 
   $ rm dangling
   $ ln -s void dangling
   $ hg commit -m 'change symlink'
   $ "$TESTDIR/readlink.py" dangling
   dangling -> void
 
 
 modifying link
 
   $ rm dangling
   $ ln -s empty dangling
   $ "$TESTDIR/readlink.py" dangling
   dangling -> empty
 
 
 reverting to rev 0:
 
   $ hg revert -r 0 -a
   reverting dangling
   $ "$TESTDIR/readlink.py" dangling
   dangling -> nothing
 
 
 backups:
 
   $ "$TESTDIR/readlink.py" *.orig
   dangling.orig -> empty
   $ rm *.orig
   $ hg up -C
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
 
 copies
 
   $ hg cp -v dangling dangling2
   copying dangling to dangling2
   $ hg st -Cmard
   A dangling2
     dangling
   $ "$TESTDIR/readlink.py" dangling dangling2
   dangling -> void
   dangling2 -> void
 
 
 Issue995: hg copy -A incorrectly handles symbolic links
 
   $ hg up -C
   0 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ mkdir dir
   $ ln -s dir dirlink
   $ hg ci -qAm 'add dirlink'
   $ mkdir newdir
   $ mv dir newdir/dir
   $ mv dirlink newdir/dirlink
   $ hg mv -A dirlink newdir/dirlink
 
   $ cd ..