[Python-Dev] Non-string keys in type dict

Thu Mar 8 02:39:40 CET 2012

Hi,
During the Language Summit 2011 (*), it was discussed that PyPy and
Jython don't support non-string key in type dict. An issue was open to
emit a warning on such dict, but the patch has not been commited yet.
I'm trying to Lib/test/crashers/losing_mro_ref.py: I wrote a patch
fixing the specific issue (keep a strong reference to the MRO during
the lookup, see #14199), but I realized that the real problem is that
we allow custom objects in the type dict.
So my question is: what is the use case of such dict? Why do we still
support it? Can't we simply raise an error if the dict contains
non-string keys?
(*) http://blog.python.org/2011/03/2011-language-summit-report.html
Victor