python-devtools fails to build with Python 3.9.0b1.

_________________________________ test_colours _________________________________

    def test_colours():
        v = sformat('hello', sformat.red)
>       assert v == '\x1b[31mhello\x1b[0m'
E       AssertionError: assert '\x1b[31mhell...[Style.resetm' == '\x1b[31mhello\x1b[0m'
E         - [31mhello[Style.resetm
E         + [31mhello[0m

tests/test_ansi.py:10: AssertionError
_____________________________ test_combine_styles ______________________________

    def test_combine_styles():
        v = sformat('hello', sformat.red, sformat.bold)
>       assert v == '\x1b[31;1mhello\x1b[0m'
E       AssertionError: assert '\x1b[31;1mhe...[Style.resetm' == '\x1b[31;1mhello\x1b[0m'
E         - [31;1mhello[Style.resetm
E         + [31;1mhello[0m

tests/test_ansi.py:20: AssertionError
________________________________ test_no_styles ________________________________

    def test_no_styles():
        v = sformat('hello')
>       assert v == 'hello\x1b[0m'
E       AssertionError: assert 'hello\x1b[Style.resetm' == 'hello\x1b[0m'
E         - hello[Style.resetm
E         + hello[0m

tests/test_ansi.py:25: AssertionError
________________________________ test_style_str ________________________________

    def test_style_str():
        v = sformat('hello', 'red')
>       assert v == '\x1b[31mhello\x1b[0m'
E       AssertionError: assert '\x1b[31mhell...[Style.resetm' == '\x1b[31mhello\x1b[0m'
E         - [31mhello[Style.resetm
E         + [31mhello[0m

tests/test_ansi.py:30: AssertionError
______________________________ test_non_str_input ______________________________

    def test_non_str_input():
        v = sformat(12.2, sformat.yellow, sformat.italic)
>       assert v == '\x1b[33;3m12.2\x1b[0m'
E       AssertionError: assert '\x1b[33;3m12...[Style.resetm' == '\x1b[33;3m12.2\x1b[0m'
E         - [33;3m12.2[Style.resetm
E         + [33;3m12.2[0m

tests/test_ansi.py:35: AssertionError
______________________________ test_print_is_tty _______________________________

    def test_print_is_tty():
        class TTYStream(io.StringIO):
            def isatty(self):
                return True
    
        stream = TTYStream()
        sprint('hello', sprint.green, file=stream)
        out = stream.getvalue()
>       assert out == '\x1b[32mhello\x1b[0m\n', repr(out)
E       AssertionError: '\x1b[32mhello\x1b[Style.resetm\n'
E       assert '\x1b[32mhell...tyle.resetm\n' == '\x1b[32mhello\x1b[0m\n'
E         - [32mhello[Style.resetm
E         + [32mhello[0m

tests/test_ansi.py:59: AssertionError
_________________________________ test_colours _________________________________

    def test_colours():
        v = debug.format(range(6))
        s = re.sub(r':\d{2,}', ':<line no>', v.str(True))
        assert s.startswith('\x1b[35mtests'), repr(s)
        s2 = strip_ansi(s)
>       assert s2 == v.str(), repr(s2)
E       AssertionError: 'tests/test_main.pytyle.resetm:202tyle.resetm test_colourstyle.resetm\n    range(6)tyle.resetm: range(0, 6) (range) len=6tyle.resetm'
E       assert 'tests/test_m...=6tyle.resetm' == 'tests/test_ma...(range) len=6'
E         - tests/test_main.pytyle.resetm:202tyle.resetm test_colourstyle.resetm
E         + tests/test_main.py:202 test_colours
E         -     range(6)tyle.resetm: range(0, 6) (range) len=6tyle.resetm
E         ?             -----------                           -----------
E         +     range(6): range(0, 6) (range) len=6

tests/test_main.py:206: AssertionError
____________________________ test_colours_warnings _____________________________

mocker = <pytest_mock.MockFixture object at 0x7f2e89bc6910>

    def test_colours_warnings(mocker):
        mocked_getouterframes = mocker.patch('inspect.getouterframes')
        mocked_getouterframes.side_effect = IndexError()
        v = debug.format('x')
        s = re.sub(r':\d{2,}', ':<line no>', v.str(True))
        assert s.startswith('\x1b[35m<unknown>'), repr(s)
        s2 = strip_ansi(s)
>       assert s2 == v.str(), repr(s2)
E       AssertionError: "<unknown>tyle.resetm:0tyle.resetm tyle.resetm (error parsing code, IndexError)tyle.resetm\n    'x' (str) len=1tyle.resetm"
E       assert '<unknown>tyl...=1tyle.resetm' == "<unknown>:0  ...' (str) len=1"
E         - <unknown>tyle.resetm:0tyle.resetm tyle.resetm (error parsing code, IndexError)tyle.resetm
E         + <unknown>:0  (error parsing code, IndexError)
E         -     'x' (str) len=1tyle.resetm
E         ?                    -----------
E         +     'x' (str) len=1

tests/test_main.py:216: AssertionError
========= 8 failed, 70 passed, 1 skipped, 6 deselected in 0.75 seconds =========

For the build logs, see:
https://copr-be.cloud.fedoraproject.org/results/@python/python3.9/fedora-rawhide-x86_64/01396658-python-devtools/

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

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.