view mercurial/node.py @ 44237:b4057d001760

merge: when rename was made on both sides, use ancestor as merge base

When both sides of a merge have renamed a file to the same place, we
would treat that as a "both created" action in merge.py. That means
that we'd use an empty diffbase. It seems better to use the copy
source as diffbase. That can be done by simply dropping code that
prevented us from doing that. I think I did it that way in
57203e0210f8 (copies: calculate mergecopies() based on pathcopies(),
2019-04-11) only to preserve the existing behavior. I also suspect it
was just an accident that it behaved that way before that commit.

Note that until fa9ad1da2e77 (merge: start using the per-side copy
dicts, 2020-01-23), it was non-deterministic (depending on iteration
order of the `allsources` set in `copies._fullcopytracing()`) which
source was used in the affected test case in test-rename-merge1.t. We
could easily have fixed that by sorting them, but now we can instead
detect the case (the TODO added in the previous patch).

Differential Revision: https://phab.mercurial-scm.org/D7974

# 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
# Adapt to Python 3 API changes. If this ends up showing up in
# profiles, we can use this version only on Python 3, and forward
# binascii.unhexlify like we used to on Python 2.
def bin(s):
    try:
        return binascii.unhexlify(s)
    except binascii.Error as e:
        raise TypeError(e)


nullrev = -1
# In hex, this is '0000000000000000000000000000000000000000'
nullid = b"\0" * 20
nullhex = hex(nullid)

# Phony node value to stand-in for new files in some uses of
# manifests.
# In hex, this is '2121212121212121212121212121212121212121'
newnodeid = b'!!!!!!!!!!!!!!!!!!!!'
# In hex, this is '3030303030303030303030303030306164646564'
addednodeid = b'000000000000000added'
# In hex, this is '3030303030303030303030306d6f646966696564'
modifiednodeid = b'000000000000modified'

wdirfilenodeids = {newnodeid, addednodeid, modifiednodeid}

# pseudo identifiers for working directory
# (they are experimental, so don't add too many dependencies on them)
wdirrev = 0x7FFFFFFF
# In hex, this is 'ffffffffffffffffffffffffffffffffffffffff'
wdirid = b"\xff" * 20
wdirhex = hex(wdirid)


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