hgdemandimport/tracing.py

automation: push changes affecting .hgtags

When I went to build the 5.1 tag using the in-repo automation, the
automatic version calculation failed to deduce the clean 5.1 version
string because we had only pushed the changeset corresponding to the 5.1
tag and not the changeset containing the 5.1 tag. So from the
perspective of the remote repo, the 5.1 tag didn't exist yet and
automatic version deduction failed.

This commit changes the `hg push` to also push all changesets affecting
the .hgtags file, ensuring the remote has up-to-date tags information.

I tested this by creating a local draft changeset with a dummy tag
value on a different DAG head and instructed the automation to build
a revision that didn't have this change to .hgtags. The tag was
successfully pushed and the built package had a version number
incorporating that tag.

Sending this to stable so the 5.1.1 automation hopefully "just works."

# Support code for event tracing in Mercurial. Lives in demandimport
# so it can also be used in demandimport.
#
# Copyright 2018 Google LLC.
#
# 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 contextlib
import os

_pipe = None
_checked = False

def _isactive():
    global _pipe, _session, _checked
    if _pipe is None:
        if _checked:
            return False
        _checked = True
        if 'HGCATAPULTSERVERPIPE' not in os.environ:
            return False
        _pipe = open(os.environ['HGCATAPULTSERVERPIPE'], 'w', 1)
        _session = os.environ.get('HGCATAPULTSESSION', 'none')
    return True

@contextlib.contextmanager
def log(whencefmt, *whenceargs):
    if not _isactive():
        yield
        return
    whence = whencefmt % whenceargs
    try:
        # Both writes to the pipe are wrapped in try/except to ignore
        # errors, as we can see mysterious errors in here if the pager
        # is active. Presumably other conditions could trigger
        # problems too.
        try:
            _pipe.write('START %s %s\n' % (_session, whence))
        except IOError:
            pass
        yield
    finally:
        try:
            _pipe.write('END %s %s\n' % (_session, whence))
        except IOError:
            pass

def counter(label, amount, *labelargs):
    if not _isactive():
        return
    l = label % labelargs
    # See above in log() for why this is in a try/except.
    try:
        _pipe.write('COUNTER %s %d %s\n' % (_session, amount, l))
    except IOError:
        pass