diff options
Diffstat (limited to 'third_party/python/jsonschema/jsonschema/exceptions.py')
| -rw-r--r-- | third_party/python/jsonschema/jsonschema/exceptions.py | 396 |
1 files changed, 396 insertions, 0 deletions
diff --git a/third_party/python/jsonschema/jsonschema/exceptions.py b/third_party/python/jsonschema/jsonschema/exceptions.py new file mode 100644 index 0000000000..87db3df3a6 --- /dev/null +++ b/third_party/python/jsonschema/jsonschema/exceptions.py @@ -0,0 +1,396 @@ +""" +Validation errors, and some surrounding helpers. +""" +from __future__ import annotations + +from collections import defaultdict, deque +from pprint import pformat +from textwrap import dedent, indent +import heapq +import itertools + +import attr + +from jsonschema import _utils + +WEAK_MATCHES: frozenset[str] = frozenset(["anyOf", "oneOf"]) +STRONG_MATCHES: frozenset[str] = frozenset() + +_unset = _utils.Unset() + + +class _Error(Exception): + def __init__( + self, + message, + validator=_unset, + path=(), + cause=None, + context=(), + validator_value=_unset, + instance=_unset, + schema=_unset, + schema_path=(), + parent=None, + type_checker=_unset, + ): + super(_Error, self).__init__( + message, + validator, + path, + cause, + context, + validator_value, + instance, + schema, + schema_path, + parent, + ) + self.message = message + self.path = self.relative_path = deque(path) + self.schema_path = self.relative_schema_path = deque(schema_path) + self.context = list(context) + self.cause = self.__cause__ = cause + self.validator = validator + self.validator_value = validator_value + self.instance = instance + self.schema = schema + self.parent = parent + self._type_checker = type_checker + + for error in context: + error.parent = self + + def __repr__(self): + return f"<{self.__class__.__name__}: {self.message!r}>" + + def __str__(self): + essential_for_verbose = ( + self.validator, self.validator_value, self.instance, self.schema, + ) + if any(m is _unset for m in essential_for_verbose): + return self.message + + schema_path = _utils.format_as_index( + container=self._word_for_schema_in_error_message, + indices=list(self.relative_schema_path)[:-1], + ) + instance_path = _utils.format_as_index( + container=self._word_for_instance_in_error_message, + indices=self.relative_path, + ) + prefix = 16 * " " + + return dedent( + f"""\ + {self.message} + + Failed validating {self.validator!r} in {schema_path}: + {indent(pformat(self.schema, width=72), prefix).lstrip()} + + On {instance_path}: + {indent(pformat(self.instance, width=72), prefix).lstrip()} + """.rstrip(), + ) + + @classmethod + def create_from(cls, other): + return cls(**other._contents()) + + @property + def absolute_path(self): + parent = self.parent + if parent is None: + return self.relative_path + + path = deque(self.relative_path) + path.extendleft(reversed(parent.absolute_path)) + return path + + @property + def absolute_schema_path(self): + parent = self.parent + if parent is None: + return self.relative_schema_path + + path = deque(self.relative_schema_path) + path.extendleft(reversed(parent.absolute_schema_path)) + return path + + @property + def json_path(self): + path = "$" + for elem in self.absolute_path: + if isinstance(elem, int): + path += "[" + str(elem) + "]" + else: + path += "." + elem + return path + + def _set(self, type_checker=None, **kwargs): + if type_checker is not None and self._type_checker is _unset: + self._type_checker = type_checker + + for k, v in kwargs.items(): + if getattr(self, k) is _unset: + setattr(self, k, v) + + def _contents(self): + attrs = ( + "message", "cause", "context", "validator", "validator_value", + "path", "schema_path", "instance", "schema", "parent", + ) + return dict((attr, getattr(self, attr)) for attr in attrs) + + def _matches_type(self): + try: + expected = self.schema["type"] + except (KeyError, TypeError): + return False + + if isinstance(expected, str): + return self._type_checker.is_type(self.instance, expected) + + return any( + self._type_checker.is_type(self.instance, expected_type) + for expected_type in expected + ) + + +class ValidationError(_Error): + """ + An instance was invalid under a provided schema. + """ + + _word_for_schema_in_error_message = "schema" + _word_for_instance_in_error_message = "instance" + + +class SchemaError(_Error): + """ + A schema was invalid under its corresponding metaschema. + """ + + _word_for_schema_in_error_message = "metaschema" + _word_for_instance_in_error_message = "schema" + + +@attr.s(hash=True) +class RefResolutionError(Exception): + """ + A ref could not be resolved. + """ + + _cause = attr.ib() + + def __str__(self): + return str(self._cause) + + +class UndefinedTypeCheck(Exception): + """ + A type checker was asked to check a type it did not have registered. + """ + + def __init__(self, type): + self.type = type + + def __str__(self): + return f"Type {self.type!r} is unknown to this type checker" + + +class UnknownType(Exception): + """ + A validator was asked to validate an instance against an unknown type. + """ + + def __init__(self, type, instance, schema): + self.type = type + self.instance = instance + self.schema = schema + + def __str__(self): + prefix = 16 * " " + + return dedent( + f"""\ + Unknown type {self.type!r} for validator with schema: + {indent(pformat(self.schema, width=72), prefix).lstrip()} + + While checking instance: + {indent(pformat(self.instance, width=72), prefix).lstrip()} + """.rstrip(), + ) + + +class FormatError(Exception): + """ + Validating a format failed. + """ + + def __init__(self, message, cause=None): + super(FormatError, self).__init__(message, cause) + self.message = message + self.cause = self.__cause__ = cause + + def __str__(self): + return self.message + + +class ErrorTree: + """ + ErrorTrees make it easier to check which validations failed. + """ + + _instance = _unset + + def __init__(self, errors=()): + self.errors = {} + self._contents = defaultdict(self.__class__) + + for error in errors: + container = self + for element in error.path: + container = container[element] + container.errors[error.validator] = error + + container._instance = error.instance + + def __contains__(self, index): + """ + Check whether ``instance[index]`` has any errors. + """ + + return index in self._contents + + def __getitem__(self, index): + """ + Retrieve the child tree one level down at the given ``index``. + + If the index is not in the instance that this tree corresponds + to and is not known by this tree, whatever error would be raised + by ``instance.__getitem__`` will be propagated (usually this is + some subclass of `LookupError`. + """ + + if self._instance is not _unset and index not in self: + self._instance[index] + return self._contents[index] + + def __setitem__(self, index, value): + """ + Add an error to the tree at the given ``index``. + """ + self._contents[index] = value + + def __iter__(self): + """ + Iterate (non-recursively) over the indices in the instance with errors. + """ + + return iter(self._contents) + + def __len__(self): + """ + Return the `total_errors`. + """ + return self.total_errors + + def __repr__(self): + total = len(self) + errors = "error" if total == 1 else "errors" + return f"<{self.__class__.__name__} ({total} total {errors})>" + + @property + def total_errors(self): + """ + The total number of errors in the entire tree, including children. + """ + + child_errors = sum(len(tree) for _, tree in self._contents.items()) + return len(self.errors) + child_errors + + +def by_relevance(weak=WEAK_MATCHES, strong=STRONG_MATCHES): + """ + Create a key function that can be used to sort errors by relevance. + + Arguments: + weak (set): + a collection of validation keywords to consider to be + "weak". If there are two errors at the same level of the + instance and one is in the set of weak validation keywords, + the other error will take priority. By default, :kw:`anyOf` + and :kw:`oneOf` are considered weak keywords and will be + superseded by other same-level validation errors. + + strong (set): + a collection of validation keywords to consider to be + "strong" + """ + def relevance(error): + validator = error.validator + return ( + -len(error.path), + validator not in weak, + validator in strong, + not error._matches_type(), + ) + return relevance + + +relevance = by_relevance() + + +def best_match(errors, key=relevance): + """ + Try to find an error that appears to be the best match among given errors. + + In general, errors that are higher up in the instance (i.e. for which + `ValidationError.path` is shorter) are considered better matches, + since they indicate "more" is wrong with the instance. + + If the resulting match is either :kw:`oneOf` or :kw:`anyOf`, the + *opposite* assumption is made -- i.e. the deepest error is picked, + since these keywords only need to match once, and any other errors + may not be relevant. + + Arguments: + errors (collections.abc.Iterable): + + the errors to select from. Do not provide a mixture of + errors from different validation attempts (i.e. from + different instances or schemas), since it won't produce + sensical output. + + key (collections.abc.Callable): + + the key to use when sorting errors. See `relevance` and + transitively `by_relevance` for more details (the default is + to sort with the defaults of that function). Changing the + default is only useful if you want to change the function + that rates errors but still want the error context descent + done by this function. + + Returns: + the best matching error, or ``None`` if the iterable was empty + + .. note:: + + This function is a heuristic. Its return value may change for a given + set of inputs from version to version if better heuristics are added. + """ + errors = iter(errors) + best = next(errors, None) + if best is None: + return + best = max(itertools.chain([best], errors), key=key) + + while best.context: + # Calculate the minimum via nsmallest, because we don't recurse if + # all nested errors have the same relevance (i.e. if min == max == all) + smallest = heapq.nsmallest(2, best.context, key=key) + if len(smallest) == 2 and key(smallest[0]) == key(smallest[1]): + return best + best = smallest[0] + return best |