fix: reduce number of tool executions By grouping together (path, ctx) pairs according to the inputs they would provide to fixer tools, we can deduplicate executions of fixer tools to significantly reduce the amount of time spent running slow tools. This change does not handle clean files in the working copy, which could still be deduplicated against the files in the checked out commit. It's a little harder to do that because the filerev is not available in the workingfilectx (and it doesn't exist for added files). Anecdotally, this change makes some real uses cases at Google 10x faster. I think we were originally hesitant to do this because the benefits weren't obvious, and implementing it efficiently is kind of tricky. If we simply memoized the formatter execution function, we would be keeping tons of file content in memory. Also included is a regression test for a corner case that I broke with my first attempt at optimizing this code. Differential Revision: https://phab.mercurial-scm.org/D11280

# stack.py - Mercurial functions for stack definition
#
#  Copyright Olivia Mackall <olivia@selenic.com> and other
#
# 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


def getstack(repo, rev=None):
    """return a sorted smartrev of the stack containing either rev if it is
    not None or the current working directory parent.

    The stack will always contain all drafts changesets which are ancestors to
    the revision and are not merges.
    """
    if rev is None:
        rev = b'.'

    revspec = b'only(%s) and not public() and not ::merge()'
    revisions = repo.revs(revspec, rev)
    revisions.sort()
    return revisions