Enable Python 3.10 wheels.

[QuLogic]

From the 3.10 release notes:

There will be no ABI changes from this point forward in the 3.10 series and the goal is that there will be as few code changes as possible.

So it is, roughly-speaking, safe to start building 3.10 wheels, but it seems we need to wait for pillow: python-pillow/Pillow#5569

I managed to fix a bug in the CI setup, but there's still something missing to get Pillow to load correctly in all tests.

[QuLogic]

It appears I was able to fix the build stages, but the testing is stymied by lack of Pillow wheels. Not sure if you want to work around that or wait for them.

[jbarlow83]

Thanks for this. I'd prefer to wait for Pillow's 3.10 wheels to be released; we have time since Python 3.10 won't be released until October.

[codecov]

Codecov Report

Merging #245 (c9ebb78) into master (74971b6) will decrease coverage by 0.15%.
The diff coverage is n/a.

❗ Current head c9ebb78 differs from pull request most recent head e53909e. Consider uploading reports for the commit e53909e to get more accurate results

@@            Coverage Diff             @@
##           master     #245      +/-   ##
==========================================
- Coverage   96.59%   96.43%   -0.16%     
==========================================
  Files          37       37              
  Lines        3877     3788      -89     
==========================================
- Hits         3745     3653      -92     
- Misses        132      135       +3     

Impacted Files	Coverage Δ
src/qpdf/parsers.cpp	96.59% <0.00%> (-1.53%)	⬇️
src/qpdf/object.cpp	95.91% <0.00%> (-1.47%)	⬇️
src/pikepdf/models/__init__.py	94.73% <0.00%> (-0.27%)	⬇️
src/pikepdf/models/metadata.py	92.50% <0.00%> (-0.14%)	⬇️
src/qpdf/pikepdf.h	95.65% <0.00%> (-0.10%)	⬇️
src/qpdf/pikepdf.cpp	98.70% <0.00%> (-0.02%)	⬇️
src/pikepdf/_methods.py	99.29% <0.00%> (-0.01%)	⬇️
src/qpdf/parsers.h	100.00% <0.00%> (ø)
src/pikepdf/jbig2.py	100.00% <0.00%> (ø)
src/pikepdf/__init__.py	100.00% <0.00%> (ø)
... and 6 more

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[QuLogic]

It looks like Pillow has 3.10 wheels now, but for some reason, 3.6 doesn't load it and uses the sdist again https://github.com/QuLogic/pikepdf/runs/3501350170?check_suite_focus=true

Maybe everything isn't fully mirrored yet and I should wait a few hours.

[QuLogic]

Also Windows fails building lxml for Python 3.10, which apparently has manylinux wheels, but not win32 or win64.

[hugovk]

Maybe something to do with upgrading from manylinux1 to manylinux2014?

• Pillow-8.3.1-cp36-cp36m-manylinux_2_5_i686.manylinux1_i686.whl
  https://pypi.org/project/Pillow/8.3.1/#files

• Pillow-8.3.2-cp36-cp36m-manylinux_2_17_aarch64.manylinux2014_aarch64.whl
  https://pypi.org/project/Pillow/8.3.2/#files

• Added Python 3.10 Linux jobs python-pillow/pillow-wheels#217

[jbarlow83]

@QuLogic Thanks for investigating. It looks to me like Pillow has moved to manylinux2014 and has stopped supporting manylinux2010. For what it's worth I complained that they should consider this is a breaking change and should bump their major version number.

Setting manylinux-x86_64-image = "manylinux2014" will make the Linux build pass on Python 3.10. As you found lxml doesn't have Windows yet.

That said, since pikepdf 3.x is just around the corner, I am strongly considering moving to manylinux2014 and dropping Python 3.6 (since it is two months from end of life) to avoid further drama. Maybe also switching from C++14 to 17.

[jbarlow83]

@hugovk I believe it does have to do with the switch to manylinux2014 - reported at python-pillow/Pillow#5701

[jbarlow83]

I've done further work on this - very like we'll need to drop Python 3.6 support and release pikepdf 4.0.
Also dropping manylinux2010 wheels and C++14 as mentioned above.

Currently everything is ready to go except that we are waiting for lxml to release Python 3.10 wheels, especially for Windows.

[jbarlow83]

Implemented in pikepdf 4.0; many thanks for this contribution which kicked off Python 3.10.