hgdemandimport/tracing.py

py3: avoid iterating over a literal bytes in highlight

In Python 3, iterating over a bytes literal yields integers. Since we
use the value in `text.replace()`, this fails on Python 3 with the
following trackback:

    Traceback (most recent call last):
      File "/usr/lib/python3/dist-packages/mercurial/hgweb/hgwebdir_mod.py", line 378, in run_wsgi
        for r in self._runwsgi(req, res):
      File "/usr/lib/python3/dist-packages/mercurial/hgweb/hgweb_mod.py", line 326, in run_wsgi
        for r in self._runwsgi(req, res, repo):
      File "/usr/lib/python3/dist-packages/mercurial/hgweb/hgweb_mod.py", line 449, in _runwsgi
        return getattr(webcommands, cmd)(rctx)
      File "/usr/lib/python3/dist-packages/mercurial/hgweb/webcommands.py", line 211, in file
        return _filerevision(web, webutil.filectx(web.repo, web.req))
      File "/usr/lib/python3/dist-packages/hgext/highlight/__init__.py", line 72, in filerevision_highlight
        pygmentize(web, b'fileline', fctx, web.tmpl)
      File "/usr/lib/python3/dist-packages/hgext/highlight/__init__.py", line 58, in pygmentize
        field, fctx, style, tmpl, guessfilenameonly=filenameonly
      File "/usr/lib/python3/dist-packages/hgext/highlight/highlight.py", line 62, in pygmentize
        text = text.replace(c, b'')
    TypeError: a bytes-like object is required, not 'int'

# 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
_session = 'none'


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