changelog: make copies related function return None or a valid value
With the previous code, existing but empty value were not "decoded", leading to
the method returning one of `None`, some valid value (`list` or `dict`) or
`b''`.
On a general basis, not explicitly checking for None is a source of bugs.
Having a clean return types will help the side-data copies code in future
changesets.
Differential Revision: https://phab.mercurial-scm.org/D7037
#!/usr/bin/env python
#
# An example hgweb CGI script, edit as necessary
# See also https://mercurial-scm.org/wiki/PublishingRepositories
# Path to repo or hgweb config to serve (see 'hg help hgweb')
config = "/path/to/repo/or/config"
# Uncomment and adjust if Mercurial is not installed system-wide
# (consult "installed modules" path from 'hg debuginstall'):
#import sys; sys.path.insert(0, "/path/to/python/lib")
# Uncomment to send python tracebacks to the browser if an error occurs:
#import cgitb; cgitb.enable()
from mercurial import demandimport; demandimport.enable()
from mercurial.hgweb import hgweb, wsgicgi
application = hgweb(config)
wsgicgi.launch(application)