How to use pure_python_mypy method in refurb

Best Python code snippet using refurb_python

mypy_visitor.py

Source:mypy_visitor.py

...64        original_hooks.append(hook.orig_hook)65    sys.path_hooks = original_hooks66    sys.path_importer_cache.clear()67@contextmanager68def pure_python_mypy() -> Iterator[None]:69    """70    Inside this context, all mypy related imports are done with the pure python71    versions.72    Any existing mypy module that was imported before needs to be reimported73    before use within the context.74    Upon exiting, the previous implementations are restored.75    """76    def loaded_mypy_modules() -> Iterator[str]:77        """Covenient block to get names of imported mypy modules"""78        for mod_name in sys.modules:79            if mod_name == "mypy" or mod_name.startswith("mypy."):80                yield mod_name81    # First, backup all imported mypy modules and remove them from sys.modules,82    # so they will not be found in resolution83    saved_mypy = {}84    for mod_name in list(loaded_mypy_modules()):85        saved_mypy[mod_name] = sys.modules.pop(mod_name)86    with prefer_pure_python_imports():87        # After the modules are clean, ensure the newly imported mypy modules88        # are their pure python versions.89        # - Pure python: methods are FunctionType90        # - Native: methods are MethodDescriptorType91        from mypy.traverser import TraverserVisitor92        assert isinstance(93            typing.cast(FunctionType, TraverserVisitor.visit_var), FunctionType94        )95        # Give back control96        yield97    # We're back and this is where we do cleanup. We'll remove all imported98    # mypy modules (pure python) and restore the previously backed-up ones99    # (allegedly native implementations)100    for mod_name in list(loaded_mypy_modules()):101        del sys.modules[mod_name]102    for mod_name, module in saved_mypy.items():103        sys.modules[mod_name] = module104def _get_class_globals(target_class: type, localns: Namespace) -> Namespace:105    """106    Get the globals namespace for the full class hierarchy that starts in107    target_class.108    This follows the recommendation of PEP-563 to resolve stringified type109    annotations at runtime.110    """111    all_globals = localns.copy()112    for base in inspect.getmro(target_class):113        all_globals.update(vars(sys.modules[base.__module__]))114    return all_globals115def _make_mappings(globalns: Namespace) -> VisitorNodeTypeMap:116    """117    Generate a mapping between the name of a visitor method in TraverserVisitor118    and the type of its first (non-self) parameter.119    """120    visitor_method_map = {}121    from mypy.traverser import TraverserVisitor122    methods = inspect.getmembers(123        TraverserVisitor,124        lambda o: inspect.isfunction(o) and o.__name__.startswith("visit_"),125    )126    for method_name, method in methods:127        method_params = list(inspect.signature(method).parameters.values())128        param_name = method_params[1].name129        method_types = typing.get_type_hints(method, globalns=globalns)130        visitor_method_map[method_name] = method_types[param_name]131    return visitor_method_map132# Capture the global namespace of the hierarchy of TraverserVisitor before we133# replace it with a short-lived pure-python version inside the context manager134# below.135_globals = _get_class_globals(mypy.traverser.TraverserVisitor, locals())136def get_mypy_visitor_mapping() -> VisitorNodeTypeMap:137    """138    Provide the visitor method name to node type mapping as it comes from Mypy.139    Resolve the mappings using the pure-python version of mypy (necessary to140    obtain method signature type info) but then ensure the types are resolved to141    their native counterparts (by passing the previously captured global142    namespace)143    """144    with pure_python_mypy():145        mapping = _make_mappings(globalns=_globals)...

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