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@samuelcolvin @dmontagu @Gr1N @tiangolo @koxudaxi @MrMrRobat @pilosus @proofit404 @nabla-c0d3 @idmitrievsky @djpetti @layday
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import inspect
import warnings
from importlib import import_module
from typing import (
TYPE_CHECKING,
Any,
Callable,
Dict,
Generator,
Iterator,
List,
Optional,
Set,
Tuple,
Type,
TypeVar,
Union,
no_type_check,
)
from .typing import AnyType, display_as_type
try:
from typing_extensions import Literal
except ImportError:
Literal = None # type: ignore
if TYPE_CHECKING:
from .main import BaseModel # noqa: F401
from .typing import SetIntStr, DictIntStrAny, IntStr, ReprArgs # noqa: F401
KeyType = TypeVar('KeyType')
def import_string(dotted_path: str) -> Any:
"""
Stolen approximately from django. Import a dotted module path and return the attribute/class designated by the
last name in the path. Raise ImportError if the import fails.
"""
try:
module_path, class_name = dotted_path.strip(' ').rsplit('.', 1)
except ValueError as e:
raise ImportError(f'"{dotted_path}" doesn\'t look like a module path') from e
module = import_module(module_path)
try:
return getattr(module, class_name)
except AttributeError as e:
raise ImportError(f'Module "{module_path}" does not define a "{class_name}" attribute') from e
def truncate(v: Union[str], *, max_len: int = 80) -> str:
"""
Truncate a value and add a unicode ellipsis (three dots) to the end if it was too long
"""
warnings.warn('`truncate` is no-longer used by pydantic and is deprecated', DeprecationWarning)
if isinstance(v, str) and len(v) > (max_len - 2):
# -3 so quote + string + … + quote has correct length
return (v[: (max_len - 3)] + '').__repr__()
try:
v = v.__repr__()
except TypeError:
v = type(v).__repr__(v) # in case v is a type
if len(v) > max_len:
v = v[: max_len - 1] + ''
return v
ExcType = Type[Exception]
def sequence_like(v: AnyType) -> bool:
return isinstance(v, (list, tuple, set, frozenset)) or inspect.isgenerator(v)
def validate_field_name(bases: List[Type['BaseModel']], field_name: str) -> None:
"""
Ensure that the field's name does not shadow an existing attribute of the model.
"""
for base in bases:
if getattr(base, field_name, None):
raise NameError(
f'Field name "{field_name}" shadows a BaseModel attribute; '
f'use a different field name with "alias=\'{field_name}\'".'
)
def lenient_issubclass(cls: Any, class_or_tuple: Union[AnyType, Tuple[AnyType, ...]]) -> bool:
return isinstance(cls, type) and issubclass(cls, class_or_tuple)
def in_ipython() -> bool:
"""
Check whether we're in an ipython environment, including jupyter notebooks.
"""
try:
eval('__IPYTHON__')
except NameError:
return False
else: # pragma: no cover
return True
def deep_update(mapping: Dict[KeyType, Any], updating_mapping: Dict[KeyType, Any]) -> Dict[KeyType, Any]:
updated_mapping = mapping.copy()
for k, v in updating_mapping.items():
if k in mapping and isinstance(mapping[k], dict) and isinstance(v, dict):
updated_mapping[k] = deep_update(mapping[k], v)
else:
updated_mapping[k] = v
return updated_mapping
def almost_equal_floats(value_1: float, value_2: float, *, delta: float = 1e-8) -> bool:
"""
Return True if two floats are almost equal
"""
return abs(value_1 - value_2) <= delta
class PyObjectStr(str):
"""
String class where repr doesn't include quotes. Useful with Representation when you want to return a string
representation of something that valid (or pseudo-valid) python.
"""
def __repr__(self) -> str:
return str(self)
class Representation:
"""
Mixin to provide __str__, __repr__, and __pretty__ methods. See #884 for more details.
__pretty__ is used by [devtools](https://python-devtools.helpmanual.io/) to provide human readable representations
of objects.
"""
def __repr_args__(self) -> 'ReprArgs':
"""
Returns the attributes to show in __str__, __repr__, and __pretty__ this is generally overridden.
Can either return:
* name - value pairs, e.g.: `[('foo_name', 'foo'), ('bar_name', ['b', 'a', 'r'])]`
* or, just values, e.g.: `[(None, 'foo'), (None, ['b', 'a', 'r'])]`
"""
attrs = ((s, getattr(self, s)) for s in self.__slots__)
return [(a, v) for a, v in attrs if v is not None]
def __repr_name__(self) -> str:
"""
Name of the instance's class, used in __repr__.
"""
return self.__class__.__name__
def __repr_str__(self, join_str: str) -> str:
return join_str.join(repr(v) if a is None else f'{a}={v!r}' for a, v in self.__repr_args__())
def __pretty__(self, fmt: Callable[[Any], Any], **kwargs: Any) -> Generator[Any, None, None]:
"""
Used by devtools (https://python-devtools.helpmanual.io/) to provide a human readable representations of objects
"""
yield self.__repr_name__() + '('
yield 1
for name, value in self.__repr_args__():
if name is not None:
yield name + '='
yield fmt(value)
yield ','
yield 0
yield -1
yield ')'
def __str__(self) -> str:
return self.__repr_str__(' ')
def __repr__(self) -> str:
return f'{self.__repr_name__()}({self.__repr_str__(", ")})'
class GetterDict(Representation):
"""
Hack to make object's smell just enough like dicts for validate_model.
We can't inherit from Mapping[str, Any] because it upsets cython so we have to implement all methods ourselves.
"""
__slots__ = ('_obj',)
def __init__(self, obj: Any):
self._obj = obj
def __getitem__(self, key: str) -> Any:
try:
return getattr(self._obj, key)
except AttributeError as e:
raise KeyError(key) from e
def get(self, key: Any, default: Any = None) -> Any:
return getattr(self._obj, key, default)
def extra_keys(self) -> Set[Any]:
"""
We don't want to get any other attributes of obj if the model didn't explicitly ask for them
"""
return set()
def keys(self) -> List[Any]:
"""
Keys of the pseudo dictionary, uses a list not set so order information can be maintained like python
dictionaries.
"""
return list(self)
def values(self) -> List[Any]:
return [self[k] for k in self]
def items(self) -> Iterator[Tuple[str, Any]]:
for k in self:
yield k, self.get(k)
def __iter__(self) -> Iterator[str]:
for name in dir(self._obj):
if not name.startswith('_'):
yield name
def __len__(self) -> int:
return sum(1 for _ in self)
def __contains__(self, item: Any) -> bool:
return item in self.keys()
def __eq__(self, other: Any) -> bool:
return dict(self) == dict(other.items()) # type: ignore
def __repr_args__(self) -> 'ReprArgs':
return [(None, dict(self))] # type: ignore
def __repr_name__(self) -> str:
return f'GetterDict[{display_as_type(self._obj)}]'
class ValueItems(Representation):
"""
Class for more convenient calculation of excluded or included fields on values.
"""
__slots__ = ('_items', '_type')
def __init__(self, value: Any, items: Union['SetIntStr', 'DictIntStrAny']) -> None:
if TYPE_CHECKING:
self._items: Union['SetIntStr', 'DictIntStrAny']
self._type: Type[Union[set, dict]] # type: ignore
# For further type checks speed-up
if isinstance(items, dict):
self._type = dict
elif isinstance(items, set):
self._type = set
else:
raise TypeError(f'Unexpected type of exclude value {type(items)}')
if isinstance(value, (list, tuple)):
items = self._normalize_indexes(items, len(value))
self._items = items
@no_type_check
def is_excluded(self, item: Any) -> bool:
"""
Check if item is fully excluded
(value considered excluded if self._type is set and item contained in self._items
or self._type is dict and self._items.get(item) is ...
:param item: key or index of a value
"""
if self._type is set:
return item in self._items
return self._items.get(item) is ...
@no_type_check
def is_included(self, item: Any) -> bool:
"""
Check if value is contained in self._items
:param item: key or index of value
"""
return item in self._items
@no_type_check
def for_element(self, e: 'IntStr') -> Optional[Union['SetIntStr', 'DictIntStrAny']]:
"""
:param e: key or index of element on value
:return: raw values for elemet if self._items is dict and contain needed element
"""
if self._type is dict:
item = self._items.get(e)
return item if item is not ... else None
return None
@no_type_check
def _normalize_indexes(
self, items: Union['SetIntStr', 'DictIntStrAny'], v_length: int
) -> Union['SetIntStr', 'DictIntStrAny']:
"""
:param items: dict or set of indexes which will be normalized
:param v_length: length of sequence indexes of which will be
>>> self._normalize_indexes({0, -2, -1}, 4)
{0, 2, 3}
"""
if self._type is set:
return {v_length + i if i < 0 else i for i in items}
else:
return {v_length + i if i < 0 else i: v for i, v in items.items()}
def __repr_args__(self) -> 'ReprArgs':
return [(None, self._items)]
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