[Distutils] wheels on sys.path clarification (reboot)

[Eric V. Smith]

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On 01/30/2014 10:23 AM, Donald Stufft wrote:
> 
> On Jan 30, 2014, at 10:12 AM, Paul Moore <p.f.moore at gmail.com>
> wrote:
> 
>> On 30 January 2014 15:03, Donald Stufft <donald at stufft.io>
>> wrote:
>>> For those following along at home who have no interest in
>>> supporting zipped Wheels who want to disclaim support for it,
>>> here's how you do zip_safe=False for Wheels:
>>> https://gist.github.com/dstufft/8710270.
>> 
>> Note that this will also prevent use in py2exe, cx_Freeze and
>> any similar bundling technologies. Presumably that's what you
>> want, as any issues are identical, but it's worth being clear.
>> 
>> Paul
> 
> Sure, using a library via zip import when it wasn’t designed to be
> used as such is an anti pattern.

The flag really needs to convey 2 meanings:
- - There are some C extensions here that can't be loaded unless they
live on a real filesystem path.
- - There is some code (maybe in this package, maybe in another package
that uses this one) that uses this package's __file__, and that code
won't work unless __file__ points to a real filesystem path.

There are any number of possible importers that would fail due to
these 2 cases. I've personally written one that loads modules from a
database. It should respect this flag, too.

Which is a long way of saying: I think calling it "zip_safe" is a
misnomer. The flag is really conveying "I don't need to be on a
filesystem".

Whether there should be 2 different flags for the two different
problems (C extension and __file__), I can't say. They do seem to go
hand-in-hand.

Eric.


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