Source code for cattrs.v

"""Cattrs validation."""

from typing import Callable, List, Union

from .errors import (
    ClassValidationError,
    ForbiddenExtraKeysError,
    IterableValidationError,
)

__all__ = ["format_exception", "transform_error"]


[docs]def format_exception(exc: BaseException, type: Union[type, None]) -> str: """The default exception formatter, handling the most common exceptions. The following exceptions are handled specially: * `KeyErrors` (`required field missing`) * `ValueErrors` (`invalid value for type, expected <type>` or just `invalid value`) * `TypeErrors` (`invalid value for type, expected <type>` and a couple special cases for iterables) * `cattrs.ForbiddenExtraKeysError` * some `AttributeErrors` (special cased for structing mappings) """ if isinstance(exc, KeyError): res = "required field missing" elif isinstance(exc, ValueError): if type is not None: tn = type.__name__ if hasattr(type, "__name__") else repr(type) res = f"invalid value for type, expected {tn}" else: res = "invalid value" elif isinstance(exc, TypeError): if type is None: if exc.args[0].endswith("object is not iterable"): res = "invalid value for type, expected an iterable" else: res = f"invalid type ({exc})" else: tn = type.__name__ if hasattr(type, "__name__") else repr(type) res = f"invalid value for type, expected {tn}" elif isinstance(exc, ForbiddenExtraKeysError): res = f"extra fields found ({', '.join(exc.extra_fields)})" elif isinstance(exc, AttributeError) and exc.args[0].endswith( "object has no attribute 'items'" ): # This was supposed to be a mapping (and have .items()) but it something else. res = "expected a mapping" elif isinstance(exc, AttributeError) and exc.args[0].endswith( "object has no attribute 'copy'" ): # This was supposed to be a mapping (and have .copy()) but it something else. # Used for TypedDicts. res = "expected a mapping" else: res = f"unknown error ({exc})" return res
[docs]def transform_error( exc: Union[ClassValidationError, IterableValidationError, BaseException], path: str = "$", format_exception: Callable[ [BaseException, Union[type, None]], str ] = format_exception, ) -> List[str]: """Transform an exception into a list of error messages. To get detailed error messages, the exception should be produced by a converter with `detailed_validation` set. By default, the error messages are in the form of `{description} @ {path}`. While traversing the exception and subexceptions, the path is formed: * by appending `.{field_name}` for fields in classes * by appending `[{int}]` for indices in iterables, like lists * by appending `[{str}]` for keys in mappings, like dictionaries :param exc: The exception to transform into error messages. :param path: The root path to use. :param format_exception: A callable to use to transform `Exceptions` into string descriptions of errors. .. versionadded:: 23.1.0 """ errors = [] if isinstance(exc, IterableValidationError): with_notes, without = exc.group_exceptions() for exc, note in with_notes: p = f"{path}[{note.index!r}]" if isinstance(exc, (ClassValidationError, IterableValidationError)): errors.extend(transform_error(exc, p, format_exception)) else: errors.append(f"{format_exception(exc, note.type)} @ {p}") for exc in without: errors.append(f"{format_exception(exc, None)} @ {path}") elif isinstance(exc, ClassValidationError): with_notes, without = exc.group_exceptions() for exc, note in with_notes: p = f"{path}.{note.name}" if isinstance(exc, (ClassValidationError, IterableValidationError)): errors.extend(transform_error(exc, p, format_exception)) else: errors.append(f"{format_exception(exc, note.type)} @ {p}") for exc in without: errors.append(f"{format_exception(exc, None)} @ {path}") else: errors.append(f"{format_exception(exc, None)} @ {path}") return errors