view hgext/fastannotate/error.py @ 39473:b6db2e80a9ce

ancestors: actually iterate over ancestors in topological order (issue5979)

This code previously used a dequeue logic, the first ancestors seen were the
first ancestors to be emitted. In branching/merging situations, it can result
in ancestors being yielded before their descendants, breaking the object
contract.

We got affected by this issue while working on the copy tracing code. At about
the same time, Axel Hecht <[e-mail]> reported the issue and provided
the test case used in this changeset. Thanks Axel.

Running `hg perfancestors` does not show a significant difference between the
old and the new version.

# 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"""