view mercurial/node.py @ 33475:f501322512b6

parsers: fix invariant bug in find_deepest (issue5623)

find_deepest is used to find the "best" ancestors given a list. In the main
loop it keeps an invariant called 'ninteresting' which is supposed to contain
the number of non-zero entries in the 'interesting' array. This invariant is
incorrectly maintained, however, which leads the the algorithm returning an
empty result for certain graphs. This has been fixed.

Also, the 'interesting' array is supposed to fit 2^ancestors values, but is
incorrectly allocated to twice that size. This has been fixed as well.

The tests in test-ancestor.py compare the Python and C versions of the code,
and report the error correctly, since the Python version works correct. Even
so, I have added an additional test against the expected result, in the event
that both algorithms have an identical error in the future.

This fixes issue5623.

# 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])