305 lines
11 KiB
Python
305 lines
11 KiB
Python
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import inspect
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from inspect import Parameter
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from types import FunctionType
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from typing import Callable, Dict, Optional, Tuple, Type, TypeVar, Union, get_type_hints
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from .typing_utils import get_args, issubtype
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_WrappedMethod = TypeVar("_WrappedMethod", bound=Union[FunctionType, Callable])
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_WrappedMethod2 = TypeVar("_WrappedMethod2", bound=Union[FunctionType, Callable])
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def _contains_unbound_typevar(t: Type) -> bool:
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"""Recursively check if `t` or any types contained by `t` is a `TypeVar`.
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Examples where we return `True`: `T`, `Optional[T]`, `Tuple[Optional[T], ...]`, ...
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Examples where we return `False`: `int`, `Optional[str]`, ...
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:param t: Type to evaluate.
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:return: `True` if the input type contains an unbound `TypeVar`, `False` otherwise.
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"""
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# Check self
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if isinstance(t, TypeVar):
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return True
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# Check children
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for arg in get_args(t):
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if _contains_unbound_typevar(arg):
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return True
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return False
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def _issubtype(left, right):
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if _contains_unbound_typevar(left):
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return True
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if right is None:
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return True
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if _contains_unbound_typevar(right):
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return True
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try:
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return issubtype(left, right)
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except TypeError:
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# Ignore all broken cases
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return True
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def _get_type_hints(callable) -> Optional[Dict]:
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try:
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return get_type_hints(callable)
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except (NameError, TypeError):
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return None
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def _is_same_module(callable1: _WrappedMethod, callable2: _WrappedMethod2) -> bool:
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mod1 = callable1.__module__.split(".")[0]
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try:
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mod2 = callable2.__module__
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except AttributeError:
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return False
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mod2 = mod2.split(".")[0]
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return mod1 == mod2
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def ensure_signature_is_compatible(
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super_callable: _WrappedMethod,
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sub_callable: _WrappedMethod2,
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is_static: bool = False,
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) -> None:
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"""Ensure that the signature of `sub_callable` is compatible with the signature of `super_callable`.
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Guarantees that any call to `super_callable` will work on `sub_callable` by checking the following criteria:
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1. The return type of `sub_callable` is a subtype of the return type of `super_callable`.
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2. All parameters of `super_callable` are present in `sub_callable`, unless `sub_callable`
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declares `*args` or `**kwargs`.
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3. All positional parameters of `super_callable` appear in the same order in `sub_callable`.
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4. All parameters of `super_callable` are a subtype of the corresponding parameters of `sub_callable`.
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5. All required parameters of `sub_callable` are present in `super_callable`, unless `super_callable`
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declares `*args` or `**kwargs`.
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:param super_callable: Function to check compatibility with.
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:param sub_callable: Function to check compatibility of.
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:param is_static: True if staticmethod and should check first argument.
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"""
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super_callable = _unbound_func(super_callable)
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sub_callable = _unbound_func(sub_callable)
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try:
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super_sig = inspect.signature(super_callable)
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except ValueError:
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return
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super_type_hints = _get_type_hints(super_callable)
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sub_sig = inspect.signature(sub_callable)
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sub_type_hints = _get_type_hints(sub_callable)
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method_name = sub_callable.__qualname__
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same_main_module = _is_same_module(sub_callable, super_callable)
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if super_type_hints is not None and sub_type_hints is not None:
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ensure_return_type_compatibility(super_type_hints, sub_type_hints, method_name)
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ensure_all_kwargs_defined_in_sub(
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super_sig, sub_sig, super_type_hints, sub_type_hints, is_static, method_name
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)
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ensure_all_positional_args_defined_in_sub(
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super_sig,
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sub_sig,
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super_type_hints,
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sub_type_hints,
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is_static,
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same_main_module,
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method_name,
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)
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ensure_no_extra_args_in_sub(super_sig, sub_sig, is_static, method_name)
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def _unbound_func(callable: _WrappedMethod) -> _WrappedMethod:
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if hasattr(callable, "__self__") and hasattr(callable, "__func__"):
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return callable.__func__ # type: ignore
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return callable
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def ensure_all_kwargs_defined_in_sub(
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super_sig: inspect.Signature,
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sub_sig: inspect.Signature,
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super_type_hints: Dict,
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sub_type_hints: Dict,
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check_first_parameter: bool,
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method_name: str,
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):
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sub_has_var_kwargs = any(
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p.kind == Parameter.VAR_KEYWORD for p in sub_sig.parameters.values()
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)
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for super_index, (name, super_param) in enumerate(super_sig.parameters.items()):
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if super_index == 0 and not check_first_parameter:
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continue
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if super_param.kind == Parameter.VAR_POSITIONAL:
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continue
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if super_param.kind == Parameter.POSITIONAL_ONLY:
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continue
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if not is_param_defined_in_sub(
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name, True, sub_has_var_kwargs, sub_sig, super_param
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):
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raise TypeError(f"{method_name}: `{name}` is not present.")
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elif name in sub_sig.parameters and super_param.kind != Parameter.VAR_KEYWORD:
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sub_index = list(sub_sig.parameters.keys()).index(name)
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sub_param = sub_sig.parameters[name]
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if super_param.kind != sub_param.kind and not (
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super_param.kind == Parameter.KEYWORD_ONLY
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and sub_param.kind == Parameter.POSITIONAL_OR_KEYWORD
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):
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raise TypeError(f"{method_name}: `{name}` is not `{super_param.kind}`")
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elif super_index > sub_index and super_param.kind != Parameter.KEYWORD_ONLY:
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raise TypeError(
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f"{method_name}: `{name}` is not parameter at index `{super_index}`"
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)
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elif (
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name in super_type_hints
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and name in sub_type_hints
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and not _issubtype(super_type_hints[name], sub_type_hints[name])
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):
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raise TypeError(
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f"`{method_name}: {name} must be a supertype of `{super_param.annotation}` but is `{sub_param.annotation}`"
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)
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def ensure_all_positional_args_defined_in_sub(
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super_sig: inspect.Signature,
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sub_sig: inspect.Signature,
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super_type_hints: Dict,
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sub_type_hints: Dict,
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check_first_parameter: bool,
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is_same_main_module: bool,
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method_name: str,
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):
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sub_parameter_values = [
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v
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for v in sub_sig.parameters.values()
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if v.kind not in (Parameter.KEYWORD_ONLY, Parameter.VAR_KEYWORD)
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]
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super_parameter_values = [
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v
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for v in super_sig.parameters.values()
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if v.kind not in (Parameter.KEYWORD_ONLY, Parameter.VAR_KEYWORD)
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]
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sub_has_var_args = any(
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p.kind == Parameter.VAR_POSITIONAL for p in sub_parameter_values
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)
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super_has_var_args = any(
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p.kind == Parameter.VAR_POSITIONAL for p in super_parameter_values
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)
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if not sub_has_var_args and len(sub_parameter_values) < len(super_parameter_values):
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raise TypeError(f"{method_name}: parameter list too short")
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super_shift = 0
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for index, sub_param in enumerate(sub_parameter_values):
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if index == 0 and not check_first_parameter:
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continue
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if index + super_shift >= len(super_parameter_values):
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if sub_param.kind == Parameter.VAR_POSITIONAL:
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continue
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if (
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sub_param.kind == Parameter.POSITIONAL_ONLY
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and sub_param.default != Parameter.empty
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):
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continue
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if sub_param.kind == Parameter.POSITIONAL_OR_KEYWORD:
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continue # Assume use as keyword
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raise TypeError(
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f"{method_name}: `{sub_param.name}` positionally required in subclass but not in supertype"
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)
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if sub_param.kind == Parameter.VAR_POSITIONAL:
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return
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super_param = super_parameter_values[index + super_shift]
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if super_param.kind == Parameter.VAR_POSITIONAL:
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super_shift -= 1
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if super_param.kind == Parameter.VAR_POSITIONAL:
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if not sub_has_var_args:
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raise TypeError(f"{method_name}: `{super_param.name}` must be present")
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continue
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if (
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super_param.kind != sub_param.kind
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and not (
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super_param.kind == Parameter.POSITIONAL_ONLY
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and sub_param.kind == Parameter.POSITIONAL_OR_KEYWORD
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)
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and not (sub_param.kind == Parameter.POSITIONAL_ONLY and super_has_var_args)
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):
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raise TypeError(
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f"{method_name}: `{sub_param.name}` is not `{super_param.kind}` and is `{sub_param.kind}`"
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)
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elif (
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super_param.name in super_type_hints or is_same_main_module
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) and not _issubtype(
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super_type_hints.get(super_param.name, None),
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sub_type_hints.get(sub_param.name, None),
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):
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raise TypeError(
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f"`{method_name}: {sub_param.name} overriding must be a supertype of `{super_param.annotation}` but is `{sub_param.annotation}`"
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)
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def is_param_defined_in_sub(
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name: str,
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sub_has_var_args: bool,
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sub_has_var_kwargs: bool,
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sub_sig: inspect.Signature,
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super_param: inspect.Parameter,
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) -> bool:
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return (
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name in sub_sig.parameters
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or (super_param.kind == Parameter.VAR_POSITIONAL and sub_has_var_args)
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or (super_param.kind == Parameter.VAR_KEYWORD and sub_has_var_kwargs)
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or (super_param.kind == Parameter.POSITIONAL_ONLY and sub_has_var_args)
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or (
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super_param.kind == Parameter.POSITIONAL_OR_KEYWORD
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and sub_has_var_args
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and sub_has_var_kwargs
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)
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or (super_param.kind == Parameter.KEYWORD_ONLY and sub_has_var_kwargs)
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)
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def ensure_no_extra_args_in_sub(
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super_sig: inspect.Signature,
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sub_sig: inspect.Signature,
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check_first_parameter: bool,
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method_name: str,
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) -> None:
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super_params = super_sig.parameters.values()
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super_var_args = any(p.kind == Parameter.VAR_POSITIONAL for p in super_params)
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super_var_kwargs = any(p.kind == Parameter.VAR_KEYWORD for p in super_params)
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for sub_index, (name, sub_param) in enumerate(sub_sig.parameters.items()):
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if (
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sub_param.kind == Parameter.POSITIONAL_ONLY
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and len(super_params) > sub_index
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and list(super_params)[sub_index].kind == Parameter.POSITIONAL_ONLY
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):
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continue
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if (
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name not in super_sig.parameters
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and sub_param.default == Parameter.empty
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and sub_param.kind != Parameter.VAR_POSITIONAL
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and sub_param.kind != Parameter.VAR_KEYWORD
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and not (sub_param.kind == Parameter.KEYWORD_ONLY and super_var_kwargs)
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and not (sub_param.kind == Parameter.POSITIONAL_ONLY and super_var_args)
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and not (
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sub_param.kind == Parameter.POSITIONAL_OR_KEYWORD and super_var_args
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)
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and (sub_index > 0 or check_first_parameter)
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):
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raise TypeError(f"{method_name}: `{name}` is not a valid parameter.")
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def ensure_return_type_compatibility(
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super_type_hints: Dict, sub_type_hints: Dict, method_name: str
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):
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super_return = super_type_hints.get("return", None)
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sub_return = sub_type_hints.get("return", None)
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if not _issubtype(sub_return, super_return) and super_return is not None:
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raise TypeError(
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f"{method_name}: return type `{sub_return}` is not a `{super_return}`."
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)
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