Method get_expr_by_name

mypy/checkstrformat.py:514–539

Get named replacement expression from '{name}'.format(name=...) call. If the type is from **kwargs, return TempNode( ). Return None in case of an error.

(self, key: str, call: CallExpr)

        return TempNode(map_instance_to_supertype(varargs_type, iter_info).args[0])

    def get_expr_by_name(self, key: str, call: CallExpr) -> Expression | None:
        """Get named replacement expression from '{name}'.format(name=...) call.

        If the type is from **kwargs, return TempNode(<item type>). Return None in case of
        an error.
        """
        named_args = [
            arg
            for arg, kind, name in zip(call.args, call.arg_kinds, call.arg_names)
            if kind == ARG_NAMED and name == key
        ]
        if named_args:
            return named_args[0]
        star_args_2 = [arg for arg, kind in zip(call.args, call.arg_kinds) if kind == ARG_STAR2]
        if not star_args_2:
            return None
        star_arg_2 = star_args_2[0]
        kwargs_type = get_proper_type(self.chk.lookup_type(star_arg_2))
        if not isinstance(kwargs_type, Instance) or not kwargs_type.type.has_base(
            "typing.Mapping"
        ):
            # Error should be already reported.
            return TempNode(AnyType(TypeOfAny.special_form))
        any_type = AnyType(TypeOfAny.special_form)
        mapping_info = self.chk.named_generic_type("typing.Mapping", [any_type, any_type]).type
        return TempNode(map_instance_to_supertype(kwargs_type, mapping_info).args[1])

    def auto_generate_keys(self, all_specs: list[ConversionSpecifier], ctx: Context) -> bool:
        """Translate '{} {name} {}' to '{0} {name} {1}'.