wireprotov2: change how revisions are specified to changesetdata
Right now, we have a handful of arguments for specifying the revisions
whose data should be returned. Defining how all these arguments
interact when various combinations are present is difficult.
This commit establishes a new, generic mechanism for specifying
revisions. Instead of a hodgepodge of arguments defining things, we
have a list of dicts that specify revision selectors. The final set
of revisions is a union of all these selectors.
We implement support for specifying revisions based on:
* An explicit list of changeset revisions
* An explicit list of changeset revisions plus ancestry depth
* A DAG range between changeset roots and heads
If you squint hard enough, this problem has already been solved by
revsets. But I'm reluctant to expose revsets to the wire protocol
because that would require servers to implement a revset parser.
Plus there are security and performance implications: the set
of revision selectors needs to be narrowly and specifically tailored
for what is appropriate to be executing on a server. Perhaps there
would be a way for us to express the "parse tree" of a revset
query, for example. I'm not sure. We can explore this space another
time. For now, the new mechanism should bring sufficient flexibility
while remaining relatively simple.
The selector "types" are prefixed with "changeset" because I plan
to add manifest and file-flavored selectors as well. This will enable
us to e.g. select file revisions based on a range of changeset
revisions.
Differential Revision: https://phab.mercurial-scm.org/D4979
# rewriteutil.py - utility functions for rewriting changesets
#
# Copyright 2017 Octobus <contact@octobus.net>
#
# 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)