view mercurial/node.py @ 34968:3649c3f2cd90

revert: do not reverse hunks in interactive when REV is not parent (issue5096)

And introduce a new "apply" operation verb for this case as suggested in
issue5096. This replaces the no longer used "revert" operation.

In interactive revert, when reverting to something else that the parent
revision, display an "apply this change" message with a diff that is not
reversed.

The rationale is that `hg revert -i -r REV` will show hunks of the diff from
the working directory to REV and prompt the user to select them for applying
(to working directory). This contradicts dcc56e10c23b in which it was
decided to have the "direction" of prompted hunks reversed. Later on
[1], there was a broad consensus (but no decision) towards the "as to
be applied direction". Now that --interactive is no longer experimental
(5910db5d1913), it's time to switch and thus we drop no longer used
"experimental.revertalternateinteractivemode" configuration option.

[1]: https://www.mercurial-scm.org/pipermail/mercurial-devel/2016-November/090142.html


.. feature::

  When interactive revert is run against a revision other than the working
  directory parent, the diff shown is the diff to *apply* to the working directory,
  rather than the diff to *discard* from the working copy. This is in line with
  related user experiences with `git` and appears to be less confusing with
  `ui.interface=curses`.

# node.py - basic nodeid manipulation for mercurial
#
# Copyright 2005, 2006 Matt Mackall <[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

import binascii

# This ugly style has a noticeable effect in manifest parsing
hex = binascii.hexlify
bin = binascii.unhexlify

nullrev = -1
nullid = b"\0" * 20
nullhex = hex(nullid)

# Phony node value to stand-in for new files in some uses of
# manifests.
newnodeid = '!' * 20
addednodeid = ('0' * 15) + 'added'
modifiednodeid = ('0' * 12) + 'modified'

wdirnodes = {newnodeid, addednodeid, modifiednodeid}

# pseudo identifiers for working directory
# (they are experimental, so don't add too many dependencies on them)
wdirrev = 0x7fffffff
wdirid = b"\xff" * 20
wdirhex = hex(wdirid)

def short(node):
    return hex(node[:6])