tests/revnamesext.py

rust-matchers: remove default implementations for `Matcher` trait

We don't expect a whole lot of matchers to be defined, and this makes it more
obvious what a matcher does by reading its `impl Matcher for FooMatcher`.

This patch has the added benefit of fixing the `AlwaysMatcher`, its `matches`
function differs from the former default.

Differential Revision: https://phab.mercurial-scm.org/D7255

# Dummy extension to define a namespace containing revision names

from __future__ import absolute_import

from mercurial import namespaces


def reposetup(ui, repo):
    names = {b'r%d' % rev: repo[rev].node() for rev in repo}
    namemap = lambda r, name: names.get(name)
    nodemap = lambda r, node: [b'r%d' % repo[node].rev()]

    ns = namespaces.namespace(
        b'revnames',
        templatename=b'revname',
        logname=b'revname',
        listnames=lambda r: names.keys(),
        namemap=namemap,
        nodemap=nodemap,
    )
    repo.names.addnamespace(ns)