comparison hgext/rebase.py @ 33863:3160876c6e4e

rebase: choose merge base without unwanted revisions

Previously, when there are 2 merge base candidates, we choose p1 blindly,
which may make the merge result to have "unwanted content". This patch makes
rebase smarter - choose a merge base that does not have "unwanted revs" if
possible. Since we don't really have a good solution when there are
"unwanted revs", abort in that case.

Differential Revision: https://phab.mercurial-scm.org/D340

33860:3cfc9070245f

            # If one parent becomes an ancestor of the other, drop the ancestor
            for j, x in enumerate(newps[:i]):
                if x == nullrev:
                    continue
                if isancestor(np, x):
                    np = nullrev
                elif isancestor(x, np):
                    newps[j] = np
                    np = nullrev
                    bases[j], bases[i] = bases[i], bases[j]

            newps[i] = np

        # "rebasenode" updates to new p1, and the old p1 will be used as merge

        #   A B D
        if set(newps) == set(oldps) and dest not in newps:
            raise error.Abort(_('cannot rebase %d:%s without '
                                'moving at least one of its parents')
                              % (rev, repo[rev]))

    repo.ui.debug(" future parents are %d and %d\n" % tuple(newps))

    # "rebasenode" updates to new p1, use the corresponding merge base.
    if bases[0] != nullrev:
        base = bases[0]
    else:

    #
    # But our merge base candidates (D and E in above case) could still be
    # better than the default (ancestor(F, Z) == null). Therefore still
    # pick one (so choose p1 above).
    if sum(1 for b in bases if b != nullrev) > 1:
        assert base is not None

        # Revisions in the side (not chosen as merge base) branch that might
        # contain "surprising" contents
        siderevs = list(repo.revs('((%ld-%d) %% (%d+%d))',
                                  bases, base, base, dest))

        # If those revisions are covered by rebaseset, the result is good.
        # A merge in rebaseset would be considered to cover its ancestors.
        if siderevs:
            rebaseset = [r for r, d in state.items() if d > 0]
            merges = [r for r in rebaseset if cl.parentrevs(r)[1] != nullrev]
            unwantedrevs = list(repo.revs('%ld - (::%ld) - %ld',
                                          siderevs, merges, rebaseset))

            # For revs not covered, it is worth a warning.
            if unwantedrevs:
                repo.ui.warn(
                    _('warning: rebasing %d:%s may include unwanted changes '
                      'from %s\n')
                    % (rev, repo[rev], ', '.join('%d:%s' % (r, repo[r])
                                                 for r in unwantedrevs)))

    return newps[0], newps[1], base

def isagitpatch(repo, patchname):
    'Return true if the given patch is in git format'

33863:3160876c6e4e

            # If one parent becomes an ancestor of the other, drop the ancestor
            for j, x in enumerate(newps[:i]):
                if x == nullrev:
                    continue
                if isancestor(np, x): # CASE-1
                    np = nullrev
                elif isancestor(x, np): # CASE-2
                    newps[j] = np
                    np = nullrev
                    # New parents forming an ancestor relationship does not
                    # mean the old parents have a similar relationship. Do not
                    # set bases[x] to nullrev.
                    bases[j], bases[i] = bases[i], bases[j]

            newps[i] = np

        # "rebasenode" updates to new p1, and the old p1 will be used as merge

        #   A B D
        if set(newps) == set(oldps) and dest not in newps:
            raise error.Abort(_('cannot rebase %d:%s without '
                                'moving at least one of its parents')
                              % (rev, repo[rev]))

    # "rebasenode" updates to new p1, use the corresponding merge base.
    if bases[0] != nullrev:
        base = bases[0]
    else:

    #
    # But our merge base candidates (D and E in above case) could still be
    # better than the default (ancestor(F, Z) == null). Therefore still
    # pick one (so choose p1 above).
    if sum(1 for b in bases if b != nullrev) > 1:
        unwanted = [None, None] # unwanted[i]: unwanted revs if choose bases[i]
        for i, base in enumerate(bases):
            if base == nullrev:
                continue
            # Revisions in the side (not chosen as merge base) branch that
            # might contain "surprising" contents
            siderevs = list(repo.revs('((%ld-%d) %% (%d+%d))',
                                      bases, base, base, dest))

            # If those revisions are covered by rebaseset, the result is good.
            # A merge in rebaseset would be considered to cover its ancestors.
            if siderevs:
                rebaseset = [r for r, d in state.items() if d > 0]
                merges = [r for r in rebaseset
                          if cl.parentrevs(r)[1] != nullrev]
                unwanted[i] = list(repo.revs('%ld - (::%ld) - %ld',
                                             siderevs, merges, rebaseset))

        # Choose a merge base that has a minimal number of unwanted revs.
        l, i = min((len(revs), i)
                   for i, revs in enumerate(unwanted) if revs is not None)
        base = bases[i]

        # newps[0] should match merge base if possible. Currently, if newps[i]
        # is nullrev, the only case is newps[i] and newps[j] (j < i), one is
        # the other's ancestor. In that case, it's fine to not swap newps here.
        # (see CASE-1 and CASE-2 above)
        if i != 0 and newps[i] != nullrev:
            newps[0], newps[i] = newps[i], newps[0]

        # The merge will include unwanted revisions. Abort now. Revisit this if
        # we have a more advanced merge algorithm that handles multiple bases.
        if l > 0:
            unwanteddesc = _(' or ').join(
                (', '.join('%d:%s' % (r, repo[r]) for r in revs)
                 for revs in unwanted if revs is not None))
            raise error.Abort(
                _('rebasing %d:%s will include unwanted changes from %s')
                % (rev, repo[rev], unwanteddesc))

    repo.ui.debug(" future parents are %d and %d\n" % tuple(newps))

    return newps[0], newps[1], base

def isagitpatch(repo, patchname):
    'Return true if the given patch is in git format'