view hgdemandimport/tracing.py @ 48006:1fda8c9358ce

typing: add a fake `__init__()` to bytestr to distract pytype

I'm not sure what changed before pytype 09-09-2021 (from 04-15-2021), but these
started getting flagged.  This wrapping an exception in a `bytestr` pattern has
been flagged before, and I've fixed it then with `stringutil.forcebytestr()`.
But that doesn't work here, because it would create a circular import.

I suspect the issue is `bytes.__new__()` wants `Iterable[int]`, so it just
assumes the subclass will also take that.  The referenced pytype bug isn't an
exact match, but seems related and the suggested workaround helps.

The specific warnings fixed are:

    File "/mnt/c/Users/Matt/hg/mercurial/encoding.py", line 212, in tolocal: Function bytestr.__init__ was called with the wrong arguments [wrong-arg-types]
             Expected: (self, ints: Iterable[int])
      Actually passed: (self, ints: LookupError)
      Attributes of protocol Iterable[int] are not implemented on LookupError: __iter__
    Called from (traceback):
      line 353, in current file
    File "/mnt/c/Users/Matt/hg/mercurial/encoding.py", line 240, in fromlocal: Function bytestr.__init__ was called with the wrong arguments [wrong-arg-types]
             Expected: (self, ints: Iterable[int])
      Actually passed: (self, ints: UnicodeDecodeError)
      Attributes of protocol Iterable[int] are not implemented on UnicodeDecodeError: __iter__

Differential Revision: https://phab.mercurial-scm.org/D11466

# 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