Use more standard __version__ rather than PILLOW_VERSION

[hugovk]

They're both the same thing:

https://github.com/python-pillow/Pillow/blob/master/src/PIL/__init__.py

[bgilbert]

Hi, thanks for the PR. __version__ is only available in Pillow ≥ 3.4.0. As the comment says on the preceding line, PILLOW_VERSION is available in Pillow ≥ 2.1.0, so this change appears to make the Pillow detection strictly worse. What problem is this PR intended to solve?

[hugovk]

We're considering removing PILLOW_VERSION from Pillow in a future major release, as it was a hack we should probably fix.

How about requiring Pillow ≥ 3.4.0 in setup.py?

openslide-python/setup.py

Lines 52 to 54 in 78397ce

	install_requires=[
	'Pillow',
	],

Pillow 3.4.0 was released in October 2016. Since 2.1.0, there have been security fixes in 2.3.1, 2.3.2, 2.5.2, 2.5.3, 2.7.0, 3.1.1, 3.1.2 and 3.3.2, so it might be wise to require something newer.

https://www.cvedetails.com/product/27460/Python-Pillow.html

---

Alternatively, how about a try/except for __version/PILLOW_VERSION?

[bgilbert]

Thanks for the additional info. We don't control what version of PIL or Pillow the user has on their system, though. For example, Ubuntu 14.04 LTS ships Pillow 2.3.0 (hopefully with backported security fixes).

What about

have_optimizations and not (hasattr(Image, 'PILLOW_VERSION') or hasattr(Image, '__version__'))

with an appropriate comment?

[hugovk]

That looks good. I'll update it.

By the way, install_requires means you would control what version the user has: https://stackoverflow.com/a/8161816/724176

install_requires=[ 
     'Pillow >= 3.4', 
 ], 

Then when you pip install openslide-python it would install at least that version of Pillow. The "skips Pillow < 2.1.0" could be removed entirely.

[hugovk]

@bgilbert Hi, any thoughts on this? Thanks!

[hugovk]

In Pillow 7.0.0, just released:

PILLOW_VERSION has been removed. Use __version__ instead.

https://pillow.readthedocs.io/en/stable/deprecations.html#pillow-version-constant

[hugovk]

Update:

It [PILLOW_VERSION] was initially removed in Pillow 7.0.0, but brought back in 7.1.0 to give projects more time to upgrade.

https://pillow.readthedocs.io/en/stable/deprecations.html#pillow-version-constant

It'll probably be removed next year.

Closing this PR because it's over two years old. It's still relevant so I can re-open if there's any interest in merging. Thanks!

[bgilbert]

Let's keep this open for now. Since the constant has been deprecated, we'll need to change this eventually. Once we revisit which Linux distros still make sense to support, we'll have a better idea whether we still need the compat support or can just drop it.

[bgilbert]

9e9f960 updates the check to require Pillow ≥ 6.2.0 for #31, and I've switched to __version__ at the same time. So this should be fixed now.

Thanks very much for the PR and for your patience.

[hugovk]

You're welcome, and thanks!