Re: [PATCH] kunit: tool: fix typecheck errors about loading qemu configs

[David Gow]

On Fri, Oct 22, 2021 at 8:49 AM 'Daniel Latypov' via KUnit Development
<kunit-dev@xxxxxxxxxxxxxxxx> wrote:
>
> Currently, we have these errors:
> $ mypy ./tools/testing/kunit/*.py
> tools/testing/kunit/kunit_kernel.py:213: error: Item "_Loader" of "Optional[_Loader]" has no attribute "exec_module"
> tools/testing/kunit/kunit_kernel.py:213: error: Item "None" of "Optional[_Loader]" has no attribute "exec_module"
> tools/testing/kunit/kunit_kernel.py:214: error: Module has no attribute "QEMU_ARCH"
> tools/testing/kunit/kunit_kernel.py:215: error: Module has no attribute "QEMU_ARCH"
>
> exec_module
> ===========
>
> pytype currently reports no errors, but that's because there's a comment
> disabling it on 213.
>
> This is due to https://github.com/python/typeshed/pull/2626.
> The fix is to assert the loaded module implements the ABC
> (abstract base class) we want which has exec_module support.
>
> QEMU_ARCH
> =========
>
> pytype is fine with this, but mypy is not:
> https://github.com/python/mypy/issues/5059
>
> Add a check that the loaded module does indeed have QEMU_ARCH.
> Note: this is not enough to appease mypy, so we also add a comment to
> squash the warning.
>
> Signed-off-by: Daniel Latypov <dlatypov@xxxxxxxxxx>
> ---

Thanks -- this has been annoying me quite a bit, so it's good to have
it fixed. It's a bit of a shame mypy needs the additional comment, but
what can you do...

Reviewed-by: David Gow <davidgow@xxxxxxxxxx>

Cheers,
-- David

>  tools/testing/kunit/kunit_kernel.py | 15 +++++++++------
>  1 file changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/tools/testing/kunit/kunit_kernel.py b/tools/testing/kunit/kunit_kernel.py
> index faa6320e900e..c68b17905481 100644
> --- a/tools/testing/kunit/kunit_kernel.py
> +++ b/tools/testing/kunit/kunit_kernel.py
> @@ -207,12 +207,15 @@ def get_source_tree_ops_from_qemu_config(config_path: str,
>         module_path = '.' + os.path.join(os.path.basename(QEMU_CONFIGS_DIR), os.path.basename(config_path))
>         spec = importlib.util.spec_from_file_location(module_path, config_path)
>         config = importlib.util.module_from_spec(spec)
> -       # TODO(brendanhiggins@xxxxxxxxxx): I looked this up and apparently other
> -       # Python projects have noted that pytype complains that "No attribute
> -       # 'exec_module' on _importlib_modulespec._Loader". Disabling for now.
> -       spec.loader.exec_module(config) # pytype: disable=attribute-error
> -       return config.QEMU_ARCH.linux_arch, LinuxSourceTreeOperationsQemu(
> -                       config.QEMU_ARCH, cross_compile=cross_compile)
> +       # See https://github.com/python/typeshed/pull/2626 for context.
> +       assert isinstance(spec.loader, importlib.abc.Loader)
> +       spec.loader.exec_module(config)
> +
> +       if not hasattr(config, 'QEMU_ARCH'):
> +               raise ValueError('qemu_config module missing "QEMU_ARCH": ' + config_path)
> +       params: qemu_config.QemuArchParams = config.QEMU_ARCH  # type: ignore
> +       return params.linux_arch, LinuxSourceTreeOperationsQemu(
> +                       params, cross_compile=cross_compile)
>
>  class LinuxSourceTree(object):
>         """Represents a Linux kernel source tree with KUnit tests."""
>
> base-commit: 17ac23eb43f0cbefc8bfce44ad51a9f065895f9f
> --
> 2.33.0.1079.g6e70778dc9-goog
>
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