# Mercurial extension to make it easy to refer to the parent of a revision## Copyright (C) 2007 Alexis S. L. Carvalho <alexis@cecm.usp.br>## This software may be used and distributed according to the terms of the# GNU General Public License version 2, incorporated herein by reference. '''interpret suffixes to refer to ancestor revisions This extension allows you to use git-style suffixes to refer to theancestors of a specific revision. For example, if you can refer to a revision as "foo", then::   foo^N = Nth parent of foo  foo^0 = foo  foo^1 = first parent of foo  foo^2 = second parent of foo  foo^  = foo^1   foo~N = Nth first grandparent of foo  foo~0 = foo  foo~1 = foo^1 = foo^ = first parent of foo  foo~2 = foo^1^1 = foo^^ = first parent of first parent of foo'''from mercurial import error def reposetup(ui, repo):    if not repo.local():        return     class parentrevspecrepo(repo.__class__):        def lookup(self, key):            try:                _super = super(parentrevspecrepo, self)                return _super.lookup(key)            except error.RepoError:                pass             circ = key.find('^')            tilde = key.find('~')            if circ < 0 and tilde < 0:                raise            elif circ >= 0 and tilde >= 0:                end = min(circ, tilde)            else:                end = max(circ, tilde)             cl = self.changelog            base = key[:end]            try:                node = _super.lookup(base)            except error.RepoError:                # eek - reraise the first error                return _super.lookup(key)             rev = cl.rev(node)            suffix = key[end:]            i = 0            while i < len(suffix):                # foo^N => Nth parent of foo                # foo^0 == foo                # foo^1 == foo^ == 1st parent of foo                # foo^2 == 2nd parent of foo                if suffix[i] == '^':                    j = i + 1                    p = cl.parentrevs(rev)                    if j < len(suffix) and suffix[j].isdigit():                        j += 1                        n = int(suffix[i+1:j])                        if n > 2 or n == 2 and p[1] == -1:                            raise                    else:                        n = 1                    if n:                        rev = p[n - 1]                    i = j                # foo~N => Nth first grandparent of foo                # foo~0 = foo                # foo~1 = foo^1 == foo^ == 1st parent of foo                # foo~2 = foo^1^1 == foo^^ == 1st parent of 1st parent of foo                elif suffix[i] == '~':                    j = i + 1                    while j < len(suffix) and suffix[j].isdigit():                        j += 1                    if j == i + 1:                        raise                    n = int(suffix[i+1:j])                    for k in xrange(n):                        rev = cl.parentrevs(rev)[0]                    i = j                else:                    raise            return cl.node(rev)     repo.__class__ = parentrevspecrepo