mercurial/rewriteutil.py

debugcommands: allow sending of simple commands with debugwireproto

Previously, we only had support for low-level "raw" operations.

A goal of `hg debugwireproto` is to allow easily performing
higher-level primitives, such as sending a wire protocol command
and reading its response.

We implement a "command" action that does just this.

Currently, we only support simple commands (those without payloads).
We have basic support for sending command arguments. We don't yet
support sending dictionary arguments. This will be implemented later.

To prove it works, we add tests to test-ssh-proto.t that send some
"listkeys" commands.

Note: we don't observe/report os.read() events because these may not be
deterministic. We instead observe/report the read() and readline()
operations on the bufferedinputpipe. These *should* be deterministic.

Differential Revision: https://phab.mercurial-scm.org/D2406

# 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)