comparison mercurial/vfs.py @ 51883:1edac12af730

vfs: modernize the detection of the main thread

There weren't a lot of good choices when py27 was supported, but starting with
py34, `threading.main_thread()` is available.  This gets us away from an
undocumented, internal symbol, and drops a pytype suppression statement.  It is
also apparently no longer reliable after a process fork.[1][2]

[1] https://stackoverflow.com/a/23207116
[2] https://github.com/python/cpython/blob/v3.6.3/Lib/threading.py#L1334

51882:2391a5fa111e

        asynchronously, on a background thread.
        """
        # Sharing backgroundfilecloser between threads is complex and using
        # multiple instances puts us at risk of running out of file descriptors
        # only allow to use backgroundfilecloser when in main thread.
        if not isinstance(
            threading.current_thread(),
            threading._MainThread,  # pytype: disable=module-attr
        ):
            yield
            return
        vfs = getattr(self, 'vfs', self)
        if getattr(vfs, '_backgroundfilecloser', None):
            raise error.Abort(

                    )
                    % mode
                )
            fp = checkambigatclosing(fp)

        if backgroundclose and isinstance(
            threading.current_thread(),
            threading._MainThread,  # pytype: disable=module-attr
        ):
            if (
                not self._backgroundfilecloser  # pytype: disable=attribute-error
            ):
                raise error.Abort(

51883:1edac12af730

        asynchronously, on a background thread.
        """
        # Sharing backgroundfilecloser between threads is complex and using
        # multiple instances puts us at risk of running out of file descriptors
        # only allow to use backgroundfilecloser when in main thread.
        if threading.current_thread() is not threading.main_thread():
            yield
            return
        vfs = getattr(self, 'vfs', self)
        if getattr(vfs, '_backgroundfilecloser', None):
            raise error.Abort(

                    )
                    % mode
                )
            fp = checkambigatclosing(fp)

        if (
            backgroundclose
            and threading.current_thread() is threading.main_thread()
        ):
            if (
                not self._backgroundfilecloser  # pytype: disable=attribute-error
            ):
                raise error.Abort(