view hgext/parentrevspec.py @ 13733:4e2690a764c1

rebase: allow for rebasing descendants onto ancestors on different named branches

So far we've been denying rebasing descendants onto ancestors, but there are
situations in which this kind of operation makes perfect sense to me.

Let's say we have made a commit (or more), that belongs to branch 'dev', on
top of the named branch 'stable':

... a (stable) - b (dev)

but then we realize that b should belong to branch 'stable'.
In these cases a rebase means: "move these csets from named branch A to named
branch B" and there isn't a valid reason to deny it.

This patch basically doesn't block it, if source and destination are
on different named branches.
The old behaviour still applies for rebases across the same named branch.

Can you think of any tricky corner cases in which this new behaviour could
lead to problems? (I bet there are tons of them...)

By the way, I created a brand new .t because I feel there should be more
tests I can't think of at the moment.

# Mercurial extension to make it easy to refer to the parent of a revision
#
# Copyright (C) 2007 Alexis S. L. Carvalho <[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.

'''interpret suffixes to refer to ancestor revisions

This extension allows you to use git-style suffixes to refer to the
ancestors 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