[Python-Dev] PEP 376

[P.J. Eby]

At 07:11 AM 7/1/2009 +1000, Nick Coghlan wrote:
>To address PJE's question in the PEP, it may be worth expanding on this
>in the backwards compatibility section explaining how the new distutils
>metadata system avoids getting confused by the old pre-standardisation
>installation formats (e.g. it may be that the directory names and/or
>filenames all deliberately differ from current approaches precisely so
>they can coexist without interfering with each other)

In particular, it should be explicitly noted that the API does not 
support .egg files (or directories), and thus cannot substitute for 
the pkg_resources API, as far as detecting installed packages.

That is, users who need to unequivocally detect the presence/version 
of a project on sys.path, etc. will still have to use pkg_resources.

(Because pkg_resources supports the format proposed by the PEP, but 
the PEP does not support .egg files and directories.)