Py2app PIL recipe

[Christopher Barker]

Hi folks,

For a while now, PIL has provided a proper package, so that you can do:

from PIL import Image

rather than relying on a pth file and:

import Image


I'm such a fanatic about "proper" use of packages and namespaces that I
removed the PIL.pth file from my system.

Then I tried to use py2app on a program that uses PIL. It turns out that
the PIL py2app recipe has a prescript.py file that gets put into the
bundle, and it uses the old "import Image" form.

I've hacked it to use:

     try:
         import Image
     except ImportError:
         from PIL import Image # note: the newer way to import PIL
     import sys

instead, which works fine for me.

I'd really rather simple use the package form:

    from PIL import Image # note: the newer way to import PIL

all by itself, but there is some chance that that would break older PIL
installations -- or is there? when was the PIL directory made a package?

Anyway, could someone with SVN access to py2app please make this small
patch. (I've enclosed the whole file, to make it easy).

It belongs in:

py2app/recipes/PIL/prescript.py


Thanks,
-Chris





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[Ronald Oussoren]

On 2 Nov, 2009, at 20:10, Christopher Barker wrote:

> Hi folks,
>
> For a while now, PIL has provided a proper package, so that you can do:
>
> from PIL import Image
>
> rather than relying on a pth file and:
>
> import Image
>
>
> I'm such a fanatic about "proper" use of packages and namespaces that I removed the PIL.pth file from my system.
>
> Then I tried to use py2app on a program that uses PIL. It turns out that the PIL py2app recipe has a prescript.py file that gets put into the bundle, and it uses the old "import Image" form.
>
> I've hacked it to use:
>
>    try:
>        import Image
>    except ImportError:
>        from PIL import Image # note: the newer way to import PIL
>    import sys

I will commit this patch once py2apps repository gets back (I have connectivity problems to the repo at the moment)

>
> instead, which works fine for me.
>
> I'd really rather simple use the package form:
>
>   from PIL import Image # note: the newer way to import PIL
>
> all by itself, but there is some chance that that would break older PIL installations -- or is there? when was the PIL directory made a package?

I don't know, I don't even know which name is the preferred one. The PIL Handbook (<http://www.pythonware.com/library/pil/handbook/index.htm>) uses 'import Image' throughout.

Ronald

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[Christopher Barker]

Ronald Oussoren wrote:
> I will commit this patch once py2apps repository gets back (I have connectivity problems to the repo at the moment)

great, thanks.

> I don't know, I don't even know which name is the preferred one.

I'm clear on that -- every package has moved to using namespaces over
the years.

The PIL Handbook
(<http://www.pythonware.com/library/pil/handbook/index.htm>) uses
'import Image' throughout.

That's a pretty old document. I don't know what Fredrik thinks, but
given that those are the docs, it's best to support it. However, my
suggested change only effects how py2app finds PIL, I don't think it
would break any user code.

No harm in having both ways, though.

-Chris




--
Christopher Barker, Ph.D.
Oceanographer

NOAA/OR&R/HAZMAT         [phone]   voice
7600 Sand Point Way NE   [phone]   fax
Seattle, WA  98115       [phone]   main reception
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[jalopyuser]

Ronald Oussoren <ronaldoussoren@...> wrote:

> I don't know, I don't even know which name is the preferred one. The
> PIL Handbook
> (<http://www.pythonware.com/library/pil/handbook/index.htm>) uses
> 'import Image' throughout.

Note that the on-line PIL handbook is from 4.5 years ago.

Bill
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[Ronald Oussoren]

On 24 Nov, 2009, at 20:27, Bill Janssen wrote:

> Ronald Oussoren <ronaldoussoren@...> wrote:
>
>> I don't know, I don't even know which name is the preferred one. The
>> PIL Handbook
>> (<http://www.pythonware.com/library/pil/handbook/index.htm>) uses
>> 'import Image' throughout.
>
> Note that the on-line PIL handbook is from 4.5 years ago.

Is there more recent documentation? Even the version at effbot's site <http://effbot.org/imagingbook/> says 'import Image'.

Some of the examples in the 1.1.6 distribution seem to have been converted to 'from PIL import Image', but I haven't found a definite source that says which is the prefered style.

Ronald



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[Ronald Oussoren]

On 24 Nov, 2009, at 20:06, Christopher Barker wrote:

> Ronald Oussoren wrote:
>> I will commit this patch once py2apps repository gets back (I have connectivity problems to the repo at the moment)
>
> great, thanks.

The patch is in the repo.

>
>> I don't know, I don't even know which name is the preferred one.
>
> I'm clear on that -- every package has moved to using namespaces over the years.
>
> The PIL Handbook (<http://www.pythonware.com/library/pil/handbook/index.htm>) uses 'import Image' throughout.
>
> That's a pretty old document. I don't know what Fredrik thinks, but given that those are the docs, it's best to support it. However, my suggested change only effects how py2app finds PIL, I don't think it would break any user code.
>
> No harm in having both ways, though.

I'm not 100% sure about that though, users may now end up with two copies of PIL unless they remove the .pth file as well. That wouldn't be a disaster, but I'd prefer to avoid that.

Ronald



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[Christopher Barker]

Ronald Oussoren wrote:

>> No harm in having both ways, though.
>
> I'm not 100% sure about that though, users may now end up with two copies of PIL unless they remove the .pth file as well. That wouldn't be a disaster, but I'd prefer to avoid that.

hmm -- I suppose we should check that. I agree that it's probably not a
good idea to have the contents of the package also in sys.path, but
that's how PIL is installed now. It seems that users could have it
imported in two different ways in their own code, regardless of how
py2app imports it.

I guess the question is whether modulegraph is smart enough to realize
that they are the same thing!

-Chris






--
Christopher Barker, Ph.D.
Oceanographer

Emergency Response Division
NOAA/NOS/OR&R            [phone]   voice
7600 Sand Point Way NE   [phone]   fax
Seattle, WA  98115       [phone]   main reception

Chris.Barker@...
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[Ronald Oussoren]

On 24 Nov, 2009, at 23:08, Christopher Barker wrote:

>
>
> Ronald Oussoren wrote:
>
>>> No harm in having both ways, though.
>> I'm not 100% sure about that though, users may now end up with two copies of PIL unless they remove the .pth file as well. That wouldn't be a disaster, but I'd prefer to avoid that.
>
> hmm -- I suppose we should check that. I agree that it's probably not a good idea to have the contents of the package also in sys.path, but that's how PIL is installed now. It seems that users could have it imported in two different ways in their own code, regardless of how py2app imports it.
>
> I guess the question is whether modulegraph is smart enough to realize that they are the same thing!

The aren't according to the python rules: if you import both PIL.Image and Image you get two distinct modules in sys.modules (that is, sys.modules['Image'] is not sys.modules['PIL.Image']).  PIL isn't too large, adding it twice won't really be a problem but it would be nice to avoid this issue.

Ronald



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