mercurial/stack.py

rust: Add type annotation to fix inference on Rust Nightly

When compiling with Rust Nightly, the im-rs crate silently makes use of the
experimental language feature for trait impl specialization. This apperently
changes public its APIs in subtle ways such that type inference of some user
code can fail where it succeeds when specialization is disabled.

This made Mercurial’s Rust unit tests have compilation errors on Nightly.

I have not managed to find the exactl root cause, but I wrote down my findings
so far at https://github.com/bodil/im-rs/issues/188

This adds type annotation to make unit tests rely less on type inference
and work around the issue.

Differential Revision: https://phab.mercurial-scm.org/D10742

# stack.py - Mercurial functions for stack definition
#
#  Copyright Olivia Mackall <[e-mail]> 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