python-music21 fails to build with Python 3.9.0a3. Traceback (most recent call last): File "<string>", line 1, in <module> File "/builddir/build/BUILD/music21-2.2.1/music21/__init__.py", line 164, in <module> from music21 import * # @UnresolvedImport # pylint: disable=wildcard-import File "/builddir/build/BUILD/music21-2.2.1/music21/abcFormat/__init__.py", line 45, in <module> from music21.abcFormat import translate File "/builddir/build/BUILD/music21-2.2.1/music21/abcFormat/translate.py", line 32, in <module> from music21 import stream File "/builddir/build/BUILD/music21-2.2.1/music21/stream/__init__.py", line 52, in <module> from music21 import timespans File "/builddir/build/BUILD/music21-2.2.1/music21/timespans/__init__.py", line 37, in <module> from music21.timespans import analysis File "/builddir/build/BUILD/music21-2.2.1/music21/timespans/analysis.py", line 34, in <module> class Horizontality(collections.Sequence): AttributeError: module 'collections' has no attribute 'Sequence' See https://docs.python.org/3.9/whatsnew/3.9.html#removed "The abstract base classes in collections.abc no longer are exposed in the regular collections module. This will help create a clearer distinction between the concrete classes and the abstract base classes." For the build logs, see: https://copr-be.cloud.fedoraproject.org/results/@python/python3.9/fedora-rawhide-x86_64/01252589-python-music21/ For all our attempts to build python-music21 with Python 3.9, see: https://copr.fedorainfracloud.org/coprs/g/python/python3.9/package/python-music21/ Testing and mass rebuild of packages is happening in copr. You can follow these instructions to test locally in mock if your package builds with Python 3.9: https://copr.fedorainfracloud.org/coprs/g/python/python3.9/ Let us know here if you have any questions. Python 3.9 will be included in Fedora 33. To make that update smoother, we're building Fedora packages with early pre-releases of Python 3.9. A build failure prevents us from testing all dependent packages (transitive [Build]Requires), so if this package is required a lot, it's important for us to get it fixed soon. We'd appreciate help from the people who know this package best, but if you don't want to work on this now, let us know so we can try to work around it on our side.
The packaged version seems to have been released in 2015 . The upstream seems to have fixed all issues related to collections and made several big changes : https://github.com/cuthbertLab/music21
In Python 3.9.0a4 we have managed to revert the change that disables importing abstract base classes (collections.abc) directly form the regular collections module. It was reverted to ease transition for projects that did not yet actually dropped support for Python 2.7. The removal is scheduled for Python 3.10 instead. We are mass closing all the bug reports about build failures that were caused by this. Expect a new Bugzilla report in case this package fails to build with Python 3.9 for a different reason as well. In case you haven't done this already, we highly recommend to talk to your upstream and get this fixed anyway, because this will return in Python 3.10 and Python upstream is very unlikely to postpone this once more. In case you've already done that, thank you (this message is mass posted to all the relevant Bugzillas).