mercurial/stack.py

graft: add a new `--stop` flag to stop interrupted graft

This patch adds a new flag `--stop` to `hg graft` command which stops the
interrupted graft.

The `--stop` flag takes back you to the last successful step i.e. it will keep
your grafted commits, it will just clear the mergestate and interrupted graft
state.

The `--stop` is different from `--abort` flag as the latter also undoes all the
work done till now which is sometimes not what the user wants.

Suppose you grafted a lot of changesets, you encountered conflicts, you resolved
them, did `hg graft --continue`, again encountered conflicts, continue, again
encountered conflicts. Now you are tired of solving merge conflicts and want to
resume this sometimes later. If you use the `--abort` functionality, it will
strip your already grafted changesets, making you loose the work you have done
resolving merge conflicts.

A general goal related to this flag is to add this flag to `rebase` and
`histedit` too. The evolve command already has this --stop flag.

Tests are added for the new flag.

.. feature::

   `hg graft` now has a `--stop` flag to stop interrupted graft.

Differential Revision: https://phab.mercurial-scm.org/D3668

# stack.py - Mercurial functions for stack definition
#
#  Copyright Matt Mackall <[e-mail]> and other
#
# 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 . import (
    revsetlang,
    scmutil,
)

def getstack(repo, rev=None):
    """return a sorted smartrev of the stack containing either rev if it is
    not None or the current working directory parent.

    The stack will always contain all drafts changesets which are ancestors to
    the revision and are not merges.
    """
    if rev is None:
        rev = '.'

    revspec = 'reverse(only(%s) and not public() and not ::merge())'
    revset = revsetlang.formatspec(revspec, rev)
    revisions = scmutil.revrange(repo, [revset])
    revisions.sort()
    return revisions