59 lines
2.3 KiB
Python
59 lines
2.3 KiB
Python
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from abc import ABCMeta
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class EnforceOverridesMeta(ABCMeta):
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def __new__(mcls, name, bases, namespace, **kwargs):
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# Ignore any methods defined on the metaclass when enforcing overrides.
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for method in dir(mcls):
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if not method.startswith("__") and method != "mro":
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value = getattr(mcls, method)
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if not isinstance(value, (bool, str, int, float, tuple, list, dict)):
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setattr(getattr(mcls, method), "__ignored__", True)
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cls = super().__new__(mcls, name, bases, namespace, **kwargs)
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for name, value in namespace.items():
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mcls._check_if_overrides_final_method(name, bases)
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if not name.startswith("__"):
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value = mcls._handle_special_value(value)
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mcls._check_if_overrides_without_overrides_decorator(name, value, bases)
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return cls
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@staticmethod
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def _check_if_overrides_without_overrides_decorator(name, value, bases):
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is_override = getattr(value, "__override__", False)
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for base in bases:
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base_class_method = getattr(base, name, False)
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if (
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not base_class_method
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or not callable(base_class_method)
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or getattr(base_class_method, "__ignored__", False)
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):
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continue
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if not is_override:
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raise TypeError(
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f"Method {name} overrides method from {base} but does not have @override decorator"
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)
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@staticmethod
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def _check_if_overrides_final_method(name, bases):
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for base in bases:
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base_class_method = getattr(base, name, False)
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# `__final__` is added by `@final` decorator
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if getattr(base_class_method, "__final__", False):
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raise TypeError(
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f"Method {name} is finalized in {base}, it cannot be overridden"
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)
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@staticmethod
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def _handle_special_value(value):
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if isinstance(value, classmethod) or isinstance(value, staticmethod):
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value = value.__get__(None, dict)
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elif isinstance(value, property):
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value = value.fget
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return value
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class EnforceOverrides(metaclass=EnforceOverridesMeta):
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"Use this as the parent class for your custom classes"
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pass
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