pyflakes fails to build with Python 3.10.0a5.

=================================== FAILURES ===================================
________________________ CheckTests.test_eofSyntaxError ________________________

self = <pyflakes.test.test_api.CheckTests testMethod=test_eofSyntaxError>

        def test_eofSyntaxError(self):
            """
            The error reported for source files which end prematurely causing a
            syntax error reflects the cause for the syntax error.
            """
            with self.makeTempFile("def foo(") as sourcePath:
                if PYPY:
                    result = """\
    %s:1:7: parenthesis is never closed
    def foo(
          ^
    """ % (sourcePath,)
                else:
                    result = """\
    %s:1:9: unexpected EOF while parsing
    def foo(
            ^
    """ % (sourcePath,)
    
>               self.assertHasErrors(
                    sourcePath,
                    [result])

pyflakes/test/test_api.py:483: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
pyflakes/test/test_api.py:379: in assertHasErrors
    self.assertEqual(
E   AssertionError: Tuples differ: (1, "/tmp/tmpaxh8q5bq:1:8: '(' was never closed\ndef foo(\n       ^\n") != (1, '/tmp/tmpaxh8q5bq:1:9: unexpected EOF while parsing\ndef foo(\n        ^\n')
E   
E   First differing element 1:
E   "/tmp/tmpaxh8q5bq:1:8: '(' was never closed\ndef foo(\n       ^\n"
E   '/tmp/tmpaxh8q5bq:1:9: unexpected EOF while parsing\ndef foo(\n        ^\n'
E   
E   - (1, "/tmp/tmpaxh8q5bq:1:8: '(' was never closed\ndef foo(\n       ^\n")
E   + (1, '/tmp/tmpaxh8q5bq:1:9: unexpected EOF while parsing\ndef foo(\n        ^\n')
_____________________ CheckTests.test_multilineSyntaxError _____________________

self = <pyflakes.test.test_api.CheckTests testMethod=test_multilineSyntaxError>

        def test_multilineSyntaxError(self):
            """
            Source which includes a syntax error which results in the raised
            L{SyntaxError.text} containing multiple lines of source are reported
            with only the last line of that source.
            """
            source = """\
    def foo():
        '''
    
    def bar():
        pass
    
    def baz():
        '''quux'''
    """
    
            # Sanity check - SyntaxError.text should be multiple lines, if it
            # isn't, something this test was unprepared for has happened.
            def evaluate(source):
                exec(source)
            try:
>               evaluate(source)

pyflakes/test/test_api.py:441: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

source = "def foo():\n    '''\n\ndef bar():\n    pass\n\ndef baz():\n    '''quux'''\n"

    def evaluate(source):
>       exec(source)
E         File "<string>", line 8
E           '''quux'''
E                  ^
E       SyntaxError: unterminated triple-quoted string literal (detected at line 8)

pyflakes/test/test_api.py:439: SyntaxError

During handling of the above exception, another exception occurred:

self = <pyflakes.test.test_api.CheckTests testMethod=test_multilineSyntaxError>

        def test_multilineSyntaxError(self):
            """
            Source which includes a syntax error which results in the raised
            L{SyntaxError.text} containing multiple lines of source are reported
            with only the last line of that source.
            """
            source = """\
    def foo():
        '''
    
    def bar():
        pass
    
    def baz():
        '''quux'''
    """
    
            # Sanity check - SyntaxError.text should be multiple lines, if it
            # isn't, something this test was unprepared for has happened.
            def evaluate(source):
                exec(source)
            try:
                evaluate(source)
            except SyntaxError:
                e = sys.exc_info()[1]
                if not PYPY:
>                   self.assertTrue(e.text.count('\n') > 1)
E                   AssertionError: False is not true

pyflakes/test/test_api.py:445: AssertionError
=========================== short test summary info ============================
FAILED pyflakes/test/test_api.py::CheckTests::test_eofSyntaxError - Assertion...
FAILED pyflakes/test/test_api.py::CheckTests::test_multilineSyntaxError - Ass...
=========== 2 failed, 692 passed, 37 skipped, 3 deselected in 2.71s ============

For the build logs, see:
https://copr-be.cloud.fedoraproject.org/results/@python/python3.10/fedora-rawhide-x86_64/01955298-pyflakes/

For all our attempts to build pyflakes with Python 3.10, see:
https://copr.fedorainfracloud.org/coprs/g/python/python3.10/package/pyflakes/

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 3.10:
https://copr.fedorainfracloud.org/coprs/g/python/python3.10/

Let us know here if you have any questions.

Python 3.10 will be included in Fedora 35. To make that update smoother, we're building Fedora packages with early pre-releases of Python 3.10.
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.