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import abc |
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import dataclasses |
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import functools |
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import inspect |
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import sys |
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from dataclasses import Field, fields |
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from typing import Any, Callable, Dict, Optional, Tuple, Union, Type, get_type_hints |
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from enum import Enum |
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from marshmallow.exceptions import ValidationError |
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from dataclasses_json.utils import CatchAllVar |
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KnownParameters = Dict[str, Any] |
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UnknownParameters = Dict[str, Any] |
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class _UndefinedParameterAction(abc.ABC): |
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@staticmethod |
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@abc.abstractmethod |
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def handle_from_dict(cls, kvs: Dict[Any, Any]) -> Dict[str, Any]: |
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""" |
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Return the parameters to initialize the class with. |
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""" |
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pass |
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@staticmethod |
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def handle_to_dict(obj, kvs: Dict[Any, Any]) -> Dict[Any, Any]: |
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""" |
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Return the parameters that will be written to the output dict |
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""" |
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return kvs |
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@staticmethod |
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def handle_dump(obj) -> Dict[Any, Any]: |
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""" |
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Return the parameters that will be added to the schema dump. |
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""" |
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return {} |
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@staticmethod |
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def create_init(obj) -> Callable: |
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return obj.__init__ |
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@staticmethod |
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def _separate_defined_undefined_kvs(cls, kvs: Dict) -> \ |
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Tuple[KnownParameters, UnknownParameters]: |
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""" |
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Returns a 2 dictionaries: defined and undefined parameters |
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""" |
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class_fields = fields(cls) |
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field_names = [field.name for field in class_fields] |
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unknown_given_parameters = {k: v for k, v in kvs.items() if |
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k not in field_names} |
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known_given_parameters = {k: v for k, v in kvs.items() if |
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k in field_names} |
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return known_given_parameters, unknown_given_parameters |
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class _RaiseUndefinedParameters(_UndefinedParameterAction): |
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""" |
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This action raises UndefinedParameterError if it encounters an undefined |
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parameter during initialization. |
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""" |
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@staticmethod |
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def handle_from_dict(cls, kvs: Dict) -> Dict[str, Any]: |
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known, unknown = \ |
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_UndefinedParameterAction._separate_defined_undefined_kvs( |
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cls=cls, kvs=kvs) |
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if len(unknown) > 0: |
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raise UndefinedParameterError( |
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f"Received undefined initialization arguments {unknown}") |
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return known |
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CatchAll = Optional[CatchAllVar] |
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class _IgnoreUndefinedParameters(_UndefinedParameterAction): |
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""" |
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This action does nothing when it encounters undefined parameters. |
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The undefined parameters can not be retrieved after the class has been |
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created. |
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""" |
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@staticmethod |
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def handle_from_dict(cls, kvs: Dict) -> Dict[str, Any]: |
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known_given_parameters, _ = \ |
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_UndefinedParameterAction._separate_defined_undefined_kvs( |
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cls=cls, kvs=kvs) |
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return known_given_parameters |
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@staticmethod |
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def create_init(obj) -> Callable: |
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original_init = obj.__init__ |
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init_signature = inspect.signature(original_init) |
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@functools.wraps(obj.__init__) |
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def _ignore_init(self, *args, **kwargs): |
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known_kwargs, _ = \ |
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_CatchAllUndefinedParameters._separate_defined_undefined_kvs( |
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obj, kwargs) |
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num_params_takeable = len( |
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init_signature.parameters) - 1 |
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num_args_takeable = num_params_takeable - len(known_kwargs) |
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args = args[:num_args_takeable] |
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bound_parameters = init_signature.bind_partial(self, *args, |
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**known_kwargs) |
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bound_parameters.apply_defaults() |
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arguments = bound_parameters.arguments |
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arguments.pop("self", None) |
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final_parameters = \ |
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_IgnoreUndefinedParameters.handle_from_dict(obj, arguments) |
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original_init(self, **final_parameters) |
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return _ignore_init |
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class _CatchAllUndefinedParameters(_UndefinedParameterAction): |
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""" |
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This class allows to add a field of type utils.CatchAll which acts as a |
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dictionary into which all |
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undefined parameters will be written. |
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These parameters are not affected by LetterCase. |
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If no undefined parameters are given, this dictionary will be empty. |
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""" |
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class _SentinelNoDefault: |
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pass |
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@staticmethod |
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def handle_from_dict(cls, kvs: Dict) -> Dict[str, Any]: |
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known, unknown = _UndefinedParameterAction \ |
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._separate_defined_undefined_kvs(cls=cls, kvs=kvs) |
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catch_all_field = _CatchAllUndefinedParameters._get_catch_all_field( |
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cls=cls) |
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if catch_all_field.name in known: |
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already_parsed = isinstance(known[catch_all_field.name], dict) |
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default_value = _CatchAllUndefinedParameters._get_default( |
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catch_all_field=catch_all_field) |
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received_default = default_value == known[catch_all_field.name] |
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value_to_write: Any |
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if received_default and len(unknown) == 0: |
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value_to_write = default_value |
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elif received_default and len(unknown) > 0: |
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value_to_write = unknown |
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elif already_parsed: |
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value_to_write = known[catch_all_field.name] |
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if len(unknown) > 0: |
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value_to_write.update(unknown) |
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else: |
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error_message = f"Received input field with " \ |
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f"same name as catch-all field: " \ |
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f"'{catch_all_field.name}': " \ |
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f"'{known[catch_all_field.name]}'" |
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raise UndefinedParameterError(error_message) |
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else: |
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value_to_write = unknown |
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known[catch_all_field.name] = value_to_write |
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return known |
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@staticmethod |
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def _get_default(catch_all_field: Field) -> Any: |
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has_default = not isinstance(catch_all_field.default, |
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dataclasses._MISSING_TYPE) |
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has_default_factory = not isinstance(catch_all_field.default_factory, |
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dataclasses._MISSING_TYPE) |
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default_value: Union[ |
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Type[_CatchAllUndefinedParameters._SentinelNoDefault], Any] = _CatchAllUndefinedParameters\ |
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._SentinelNoDefault |
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if has_default: |
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default_value = catch_all_field.default |
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elif has_default_factory: |
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default_value = catch_all_field.default_factory() |
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return default_value |
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@staticmethod |
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def handle_to_dict(obj, kvs: Dict[Any, Any]) -> Dict[Any, Any]: |
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catch_all_field = \ |
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_CatchAllUndefinedParameters._get_catch_all_field(obj.__class__) |
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undefined_parameters = kvs.pop(catch_all_field.name) |
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if isinstance(undefined_parameters, dict): |
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kvs.update( |
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undefined_parameters) |
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return kvs |
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@staticmethod |
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def handle_dump(obj) -> Dict[Any, Any]: |
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catch_all_field = _CatchAllUndefinedParameters._get_catch_all_field( |
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cls=obj) |
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return getattr(obj, catch_all_field.name) |
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@staticmethod |
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def create_init(obj) -> Callable: |
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original_init = obj.__init__ |
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init_signature = inspect.signature(original_init) |
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@functools.wraps(obj.__init__) |
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def _catch_all_init(self, *args, **kwargs): |
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known_kwargs, unknown_kwargs = \ |
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_CatchAllUndefinedParameters._separate_defined_undefined_kvs( |
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obj, kwargs) |
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num_params_takeable = len( |
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init_signature.parameters) - 1 |
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if _CatchAllUndefinedParameters._get_catch_all_field( |
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obj).name not in known_kwargs: |
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num_params_takeable -= 1 |
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num_args_takeable = num_params_takeable - len(known_kwargs) |
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args, unknown_args = args[:num_args_takeable], args[ |
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num_args_takeable:] |
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bound_parameters = init_signature.bind_partial(self, *args, |
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**known_kwargs) |
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unknown_args = {f"_UNKNOWN{i}": v for i, v in |
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enumerate(unknown_args)} |
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arguments = bound_parameters.arguments |
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arguments.update(unknown_args) |
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arguments.update(unknown_kwargs) |
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arguments.pop("self", None) |
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final_parameters = _CatchAllUndefinedParameters.handle_from_dict( |
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obj, arguments) |
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original_init(self, **final_parameters) |
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return _catch_all_init |
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@staticmethod |
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def _get_catch_all_field(cls) -> Field: |
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cls_globals = vars(sys.modules[cls.__module__]) |
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types = get_type_hints(cls, globalns=cls_globals) |
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catch_all_fields = list( |
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filter(lambda f: types[f.name] == Optional[CatchAllVar], fields(cls))) |
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number_of_catch_all_fields = len(catch_all_fields) |
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if number_of_catch_all_fields == 0: |
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raise UndefinedParameterError( |
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"No field of type dataclasses_json.CatchAll defined") |
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elif number_of_catch_all_fields > 1: |
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raise UndefinedParameterError( |
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f"Multiple catch-all fields supplied: " |
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f"{number_of_catch_all_fields}.") |
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else: |
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return catch_all_fields[0] |
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class Undefined(Enum): |
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""" |
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Choose the behavior what happens when an undefined parameter is encountered |
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during class initialization. |
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""" |
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INCLUDE = _CatchAllUndefinedParameters |
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RAISE = _RaiseUndefinedParameters |
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EXCLUDE = _IgnoreUndefinedParameters |
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class UndefinedParameterError(ValidationError): |
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""" |
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Raised when something has gone wrong handling undefined parameters. |
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""" |
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pass |
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