tests/readlink.py

formatter: populate ctx from repo and node value

This will basically replace the fm.contexthint() API. I originally thought
this would be too complicated, and I wrote 8399438bc7ef "formatter: provide
hint of context keys required by template" because of that. However, I had
to add a similar mechanism for fctx templates, and the overall machinery
became way simpler than my original patch.

The test output slightly changed as {author} is no longer available in
the {manifest} context, which isn't the point this test targeted on.

#!/usr/bin/env python

from __future__ import absolute_import, print_function

import errno
import os
import sys

for f in sys.argv[1:]:
    try:
        print(f, '->', os.readlink(f))
    except OSError as err:
        if err.errno != errno.EINVAL:
            raise
        print(f, '->', f, 'not a symlink')

sys.exit(0)