I see this bug as well. At least, I *think* it's a bug!
e.g. the following fails with
facet_missing in my Django app ("KeyError at /.../... 'name'), but works without it.
response = s.query(querystring, facet='true', facet_field=facetfields, facet_limit=500, facet_missing='true', facet_mincount=1)
I can't find the clone in GitHub. Has this been fixed? I can't find the issue on Google Code. I'll gladly create a bug report, and help with applying the fix, if someone can clarify the status of this issue.
Cheers!