mercurial/rewriteutil.py

context: stop catching RepoLookupError from namespace.singlenode()

As pointed out by Yuya, the RepoLookupError was there for catching
errors from repo.branchtip(). However, since 885c0290f7d5 (localrepo:
add ignoremissing parameter to branchtip, 2014-10-16), that should no
longer happen. I think it should now be an error if a namespace raises
a RepoLookupError, so we propagate the exception up and and make it
easy to fix, rather than trying to interpret the changeid as nodeid
prefix and raise a general "unknown revision '...'" error.

I also don't think we should catch FilteredLookupError and LookupError
from the changelog.rev() call, for the same reason as above: If a
namespace returns a node that doesn't exist, we should provide a more
helpful exception than "unknown revision '...'".

Differential Revision: https://phab.mercurial-scm.org/D3145

# rewriteutil.py - utility functions for rewriting changesets
#
# Copyright 2017 Octobus <[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 __future__ import absolute_import

from .i18n import _

from . import (
    error,
    node,
    obsolete,
    revset,
)

def precheck(repo, revs, action='rewrite'):
    """check if revs can be rewritten
    action is used to control the error message.

    Make sure this function is called after taking the lock.
    """
    if node.nullrev in revs:
        msg = _("cannot %s null changeset") % (action)
        hint = _("no changeset checked out")
        raise error.Abort(msg, hint=hint)

    publicrevs = repo.revs('%ld and public()', revs)
    if len(repo[None].parents()) > 1:
        raise error.Abort(_("cannot %s while merging") % action)

    if publicrevs:
        msg = _("cannot %s public changesets") % (action)
        hint = _("see 'hg help phases' for details")
        raise error.Abort(msg, hint=hint)

    newunstable = disallowednewunstable(repo, revs)
    if newunstable:
        raise error.Abort(_("cannot %s changeset with children") % action)

def disallowednewunstable(repo, revs):
    """Checks whether editing the revs will create new unstable changesets and
    are we allowed to create them.

    To allow new unstable changesets, set the config:
        `experimental.evolution.allowunstable=True`
    """
    allowunstable = obsolete.isenabled(repo, obsolete.allowunstableopt)
    if allowunstable:
        return revset.baseset()
    return repo.revs("(%ld::) - %ld", revs, revs)