Re: PEP 420: Implicit Namespace Packages

On May 03, 2012, at 10:48 AM, Brett Cannon wrote:

>So, to the people not wanting to set __file__, that  (probably) won't fly
>because it has been documented for years that built-in modules are the only
>things that don't define __file__.

Okay, but *why* is this the rule, other than that PEP 302 says it?  IOW, PEP
302 doesn't give much of a rationale for the rule, and I suspect it just
reflected the reality back in 2002.

>Or we at least need to explain to people how to tell the difference in a
>backwards-compatible fashion.

Definitely, and I think that would be fine to include in PEP 420.

>So I would have said that had experience with the stdlib not big me on
>this. In my situation, the trace module was checking file, and if __file__
>didn't contain "<frozen>" or "<doctest" it would try to read it as a path,
>and then error out if it couldn't open the file. Now I updated it to
>startswith('<') and endswith('>'), but I wonder how many people made a
>similar whitelist approach. And while having __file__ to None or
>non-existent will take about the same amount of time to fix, it is less
>prone to silly whitelisting like what the trace module had.

See what I mean about arbitrary and underdocumented? :)

Cheers,
-Barry

_______________________________________________
Import-SIG mailing list
[email protected]
http://mail.python.org/mailman/listinfo/import-sig

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.11 (GNU/Linux)
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=Z5Os
-----END PGP SIGNATURE-----