hgext/fastannotate/error.py

extdiff: add comments and minor variable renames diffpatch()

Some variable names were now confusing as we refactored the code in a separate
function. For example, `node1a` leads to ideas why `1a` and not `1`. The
variable storing path to patch file was named as `dirX` instead of `fileX`.
Renamed these variables and added couple of comments.

Differential Revision: https://phab.mercurial-scm.org/D8689

# Copyright 2016-present Facebook. All Rights Reserved.
#
# error: errors used in fastannotate
#
# 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


class CorruptedFileError(Exception):
    pass


class CannotReuseError(Exception):
    """cannot reuse or update the cache incrementally"""