python-hglib fails to build with Python 3.9.0a2.

+ /usr/bin/python3 test.py --with-doctest
...........................................FF....EEE...................................................
======================================================================
ERROR: test_hidden (tests.test-hidden.test_hidden_context)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/builddir/build/BUILD/python-hglib-2.6.1/tests/test-hidden.py", line 68, in test_hidden
    self.client.rawcommand([b('debugobsolete'), cs1])
  File "/builddir/build/BUILD/python-hglib-2.6.1/hglib/client.py", line 263, in rawcommand
    raise error.CommandError(args, ret, out, err)
hglib.error.CommandError: (255, b'', b'abort: creating obsolete markers is not enabled on this repo')

======================================================================
ERROR: check the obsolete extension is available
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/builddir/build/BUILD/python-hglib-2.6.1/tests/test-hidden.py", line 35, in test_debugobsolete_success
    self.client.rawcommand([b('debugobsolete'), cs])
  File "/builddir/build/BUILD/python-hglib-2.6.1/hglib/client.py", line 263, in rawcommand
    raise error.CommandError(args, ret, out, err)
hglib.error.CommandError: (255, b'', b'abort: creating obsolete markers is not enabled on this repo')

======================================================================
ERROR: test the 'hidden' keyword with the 'in' method
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/builddir/build/BUILD/python-hglib-2.6.1/tests/test-hidden.py", line 47, in test_obsolete_in
    self.client.rawcommand([b('debugobsolete'), cs1])
  File "/builddir/build/BUILD/python-hglib-2.6.1/hglib/client.py", line 263, in rawcommand
    raise error.CommandError(args, ret, out, err)
hglib.error.CommandError: (255, b'', b'abort: creating obsolete markers is not enabled on this repo')

======================================================================
FAIL: test_basic (tests.test-grep.test_grep)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/builddir/build/BUILD/python-hglib-2.6.1/tests/test-grep.py", line 13, in test_basic
    self.assertEquals(list(self.client.grep(b('a'))),
AssertionError: Lists differ: [(b'a', b'a', b'b')] != [(b'a', b'0', b'a'), (b'b', b'0', b'ab')]

First differing element 0:
(b'a', b'a', b'b')
(b'a', b'0', b'a')

Second list contains 1 additional elements.
First extra element 1:
(b'b', b'0', b'ab')

- [(b'a', b'a', b'b')]
+ [(b'a', b'0', b'a'), (b'b', b'0', b'ab')]

======================================================================
FAIL: test_options (tests.test-grep.test_grep)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/builddir/build/BUILD/python-hglib-2.6.1/tests/test-grep.py", line 30, in test_options
    self.assertEquals([(b('a'), b('0')), (b('b'), b('0'))],
AssertionError: Lists differ: [(b'a', b'0'), (b'b', b'0')] != [(b'a', b'b')]

First differing element 0:
(b'a', b'0')
(b'a', b'b')

First list contains 1 additional elements.
First extra element 1:
(b'b', b'0')

- [(b'a', b'0'), (b'b', b'0')]
+ [(b'a', b'b')]


For the build logs, see:
https://copr-be.cloud.fedoraproject.org/results/@python/python3.9/fedora-rawhide-x86_64/01149032-python-hglib/

For all our attempts to build python-hglib with Python 3.9, see:
https://copr.fedorainfracloud.org/coprs/g/python/python3.9/package/python-hglib/

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.