[4.6] Define create_module()/exec_module() in AssertionRewritingHook to avoid ImportWarning

[hroncok]

__________ ERROR collecting testing/python/show_fixtures_per_test.py ___________
/usr/lib/python3.10/site-packages/py/_path/local.py:704: in pyimport
    __import__(modname)
<frozen importlib._bootstrap>:1026: in _find_and_load
    ???
<frozen importlib._bootstrap>:1005: in _find_and_load_unlocked
    ???
<frozen importlib._bootstrap>:681: in _load_unlocked
    ???
E   ImportWarning: AssertionRewritingHook.exec_module() not found; falling back to load_module()
!!!!!!!!!!!!!!!!!!! Interrupted: 59 errors during collection !!!!!!!!!!!!!!!!!!!
=========================== 59 error in 3.65 seconds ===========================

[hroncok]

This might need some tests to be adapted thou :(

=================================== FAILURES ===================================
_____________ TestAssertionRewriteHookDetails.test_reload_reloads ______________

self = <test_assertrewrite.TestAssertionRewriteHookDetails object at 0x7f9bc9d46e20>
testdir = <Testdir local('/tmp/pytest-of-mockbuild/pytest-3/test_reload_reloads0')>

    def test_reload_reloads(self, testdir):
        """Reloading a module after change picks up the change."""
        testdir.tmpdir.join("file.py").write(
            textwrap.dedent(
                """
            def reloaded():
                return False
    
            def rewrite_self():
                with open(__file__, 'w') as self:
                    self.write('def reloaded(): return True')
        """
            )
        )
        testdir.tmpdir.join("pytest.ini").write(
            textwrap.dedent(
                """
            [pytest]
            python_files = *.py
        """
            )
        )
    
        testdir.makepyfile(
            test_fun="""
            import sys
            try:
                from imp import reload
            except ImportError:
                pass
    
            def test_loader():
                import file
                assert not file.reloaded()
                file.rewrite_self()
                reload(file)
                assert file.reloaded()
            """
        )
        result = testdir.runpytest("-s")
>       result.stdout.fnmatch_lines(["* 1 passed*"])
E       Failed: nomatch: '* 1 passed*'
E           and: '============================= test session starts =============================='
E           and: 'platform linux -- Python 3.10.0a4, pytest-4.6.11, py-1.10.0, pluggy-0.13.1'
E           and: 'rootdir: /tmp/pytest-of-mockbuild/pytest-3/test_reload_reloads0, inifile: pytest.ini'
E           and: 'plugins: hypothesis-5.41.3'
E           and: 'collected 1 item'
E           and: ''
E           and: 'test_fun.py F'
E           and: ''
E           and: '=================================== FAILURES ==================================='
E           and: '_________________________________ test_loader __________________________________'
E           and: ''
E           and: '    def test_loader():'
E           and: '        import file'
E           and: '        assert not file.reloaded()'
E           and: '        file.rewrite_self()'
E           and: '        reload(file)'
E           and: '>       assert file.reloaded()'
E           and: 'E       AssertionError: assert False'
E           and: 'E        +  where False = <function reloaded at 0x7f9bc9d65790>()'
E           and: "E        +    where <function reloaded at 0x7f9bc9d65790> = <module 'file' (<_pytest.assertion.rewrite.AssertionRewritingHook object at 0x7f9bc817eeb0>)>.reloaded"
E           and: ''
E           and: 'test_fun.py:12: AssertionError'
E           and: '=========================== 1 failed in 0.01 seconds ==========================='
E           and: ''
E       remains unmatched: '* 1 passed*'

/builddir/build/BUILD/pytest-4.6.11/testing/test_assertrewrite.py:1142: Failed
----------------------------- Captured stdout call -----------------------------
============================= test session starts ==============================
platform linux -- Python 3.10.0a4, pytest-4.6.11, py-1.10.0, pluggy-0.13.1
rootdir: /tmp/pytest-of-mockbuild/pytest-3/test_reload_reloads0, inifile: pytest.ini
plugins: hypothesis-5.41.3
collected 1 item

test_fun.py F

=================================== FAILURES ===================================
_________________________________ test_loader __________________________________

    def test_loader():
        import file
        assert not file.reloaded()
        file.rewrite_self()
        reload(file)
>       assert file.reloaded()
E       AssertionError: assert False
E        +  where False = <function reloaded at 0x7f9bc9d65790>()
E        +    where <function reloaded at 0x7f9bc9d65790> = <module 'file' (<_pytest.assertion.rewrite.AssertionRewritingHook object at 0x7f9bc817eeb0>)>.reloaded

test_fun.py:12: AssertionError
=========================== 1 failed in 0.01 seconds ===========================

[hroncok]

It seems that the test is doing what it is supposed to do, but when the two new methods are added, it breaks. I have no idea how to proceed :(

[asottile]

there's two competing import hook specifications, PEP302 (which is what pytest 4.6.x uses) and PEP 451 which is the new style imports. pytest moved to PEP 451 in pytest 5.0 when dropping python 2.

the two PEPs are slightly incompatible with each other and python 2 dos not support PEP 451 so this isn't backportable

I'd suggest ignoring the warning in python3.10 for now, and/or consider dropping pytest 4.6 and using a modern version instead

the related bpo / PR are here:

• https://bugs.python.org/issue26131
• bpo-26131: Deprecate usage of load_module() python/cpython#23469

[hroncok]

consider dropping pytest 4.6 and using a modern version instead

We have pytest 4.6 in Fedora only for pytest-relaxed (needed by invoke and paramiko). All other packages use pytest 6.
I guess I'll just drop it eventually anyway, but I try to keep up.

[hroncok]

See also bitprophet/pytest-relaxed#12