mercurial/node.py

tests: add more tests of copy tracing with removed and re-added files

We had a test where the destination of a copy was removed and then
added back. This patch adds similar cases where the break in history
instead happens to the source file. There are three versions of this:

 1. The break happens before the rename.

 2. The break happens on a branch parallel to the rename (where copy
    tracing is done via the merge base)

 3. The source is added on each side of the merge base. The break in
    history is thus in the form of a deletion when going backwards to
    the merge base and the re-add happens on the other branch.

I've also added calls to `hg graft` in these cases to show the
breakage in issue 6163.

Another factor in these cases is matching nodeid (checked in
copies._tracefile()). I've made two copies each of the cases to show
the impact of that. One of these is the same as a test in
test-rename-merge1.t, so I also deleted that test from there.

Some of these tests currently fail, where "fail" is based on my
current thinking of how things should work. I had initially thought
that we should be more strict about not tracing copies across commits
where the file did not exist, but issue 6163 made me reconsider.

The only test case here that behaved differently in 4.9 is the
exact case reported in issue 6163.

Differential Revision: https://phab.mercurial-scm.org/D6599

# 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 = '!!!!!!!!!!!!!!!!!!!!'
# In hex, this is '3030303030303030303030303030306164646564'
addednodeid = '000000000000000added'
# In hex, this is '3030303030303030303030306d6f646966696564'
modifiednodeid = '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])