tests/revnamesext.py

context: stop catching RepoLookupError from namespace.singlenode()

As pointed out by Yuya, the RepoLookupError was there for catching
errors from repo.branchtip(). However, since 885c0290f7d5 (localrepo:
add ignoremissing parameter to branchtip, 2014-10-16), that should no
longer happen. I think it should now be an error if a namespace raises
a RepoLookupError, so we propagate the exception up and and make it
easy to fix, rather than trying to interpret the changeid as nodeid
prefix and raise a general "unknown revision '...'" error.

I also don't think we should catch FilteredLookupError and LookupError
from the changelog.rev() call, for the same reason as above: If a
namespace returns a node that doesn't exist, we should provide a more
helpful exception than "unknown revision '...'".

Differential Revision: https://phab.mercurial-scm.org/D3145

# 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)