annotate mercurial/version.py @ 6858:8f256bf98219

Add support for multiple possible bisect results (issue1228, issue1182)

The real reason for both issue is that bisect can not handle cases where there
are multiple possibilities for the result.

Example (from issue1228):
rev 0 -> good
rev 1 -> skipped
rev 2 -> skipped
rev 3 -> skipped
rev 4 -> bad

Note that this patch does not only fix the reported Assertion Error but also
the problem of a non converging bisect:

hg init
for i in `seq 3`; do echo $i > $i; hg add $i; hg ci -m$i; done
hg bisect -b 2
hg bisect -g 0
hg bisect -s

From this state on, you can:
 a) mark as bad forever (non converging!)
 b) mark as good to get an inconsistent state
 c) skip for the Assertion Error

Minor description and code edits by pmezard.

# Copyright (C) 2005, 2006, 2008 by Intevation GmbH
# Author(s):
# Thomas Arendsen Hein <[e-mail]>
#
# This program is free software under the GNU GPL (>=v2)
# Read the file COPYING coming with the software for details.

"""
Mercurial version
"""

import os
import re
import time

unknown_version = 'unknown'
remembered_version = False

def get_version(doreload=False):
    """Return version information if available."""
    try:
        import mercurial.__version__
        if doreload:
            reload(mercurial.__version__)
        version = mercurial.__version__.version
    except ImportError:
        version = unknown_version
    return version

def write_version(version):
    """Overwrite version file."""
    if version == get_version():
        return
    directory = os.path.dirname(__file__)
    for suffix in ['py', 'pyc', 'pyo']:
        try:
            os.unlink(os.path.join(directory, '__version__.%s' % suffix))
        except OSError:
            pass
    f = open(os.path.join(directory, '__version__.py'), 'w')
    f.write("# This file is auto-generated.\n")
    f.write("version = %r\n" % version)
    f.close()
    # reload the file we've just written
    get_version(True)

def remember_version(version=None):
    """Store version information."""
    global remembered_version
    if not version and os.path.isdir(".hg"):
        f = os.popen("hg identify")  # use real hg installation
        ident = f.read()[:-1]
        if not f.close() and ident:
            ids = ident.split(' ', 1)
            version = ids.pop(0)
            if version[-1] == '+':
                version = version[:-1]
                modified = True
            else:
                modified = False
            if version.isalnum() and ids:
                for tag in ids[0].split('/'):
                    # is a tag is suitable as a version number?
                    if re.match(r'^(\d+\.)+[\w.-]+$', tag):
                        version = tag
                        break
            if modified:
                version += time.strftime('+%Y%m%d')
    if version:
        remembered_version = True
        write_version(version)

def forget_version():
    """Remove version information."""
    if remembered_version:
        write_version(unknown_version)