Python 3.9 compatibility

[Chris Mayo]

On Python 3.9 when calling biplist.readPlistFromString():

  File ".tox/py39/lib/python3.9/site-packages/biplist/__init__.py", line 143, in readPlist
    line: raise InvalidPlistException(e)
    locals:
      InvalidPlistException = <global> <class 'biplist.InvalidPlistException'>
      e = <not found>

InvalidPlistException: module 'plistlib' has no attribute 'Data'

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In Python 3.9:

The old plistlib API has been removed, it was deprecated since Python 3.4. Use the load(), loads(), dump(), and dumps() functions. Additionally, the use_builtin_types parameter was removed, standard bytes objects are always used instead. (Contributed by Jon Janzen in bpo-36409.)

https://docs.python.org/3.9/whatsnew/3.9.html#removed

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[Alastair Houghton]

Agreed, this is a problem for one of my projects (dmgbuild). I might try to take a look at fixing it.

[Alastair Houghton]

Or I might not. It seems plistlib might have grown support for binary formats.

[Andrew Wooster]

Yeah, I would look into the plistlib binary plist support in 3.x. It seems to be, in my experience, pretty good in most use cases.

[Chris Mayo]

Thanks for the pointer and the confirmation. I’ve checked and plistlib can run our binary test.

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[Stefano Rivera]

FWIW applying this patch in Debian to use bytes: https://salsa.debian.org/python-team/packages/python-biplist/-/blob/6be085e22add23d3c1917f8e2aedb39e566d005d/debian/patches/python3.9.patch

It’s obviously not backwards compatible all the way to Python 2.6, so maybe not the approach you want to take.

[Matěj Cepl]

I don't think the Debian patch is correct. o can be legitimately of type bytes, couldn’t it?