JezK
Edit File: exc.py
# orm/exc.py # Copyright (C) 2005-2023 the SQLAlchemy authors and contributors # <see AUTHORS file> # # This module is part of SQLAlchemy and is released under # the MIT License: https://www.opensource.org/licenses/mit-license.php """SQLAlchemy ORM exceptions.""" from .. import exc as sa_exc from .. import util from ..exc import MultipleResultsFound # noqa from ..exc import NoResultFound # noqa NO_STATE = (AttributeError, KeyError) """Exception types that may be raised by instrumentation implementations.""" class StaleDataError(sa_exc.SQLAlchemyError): """An operation encountered database state that is unaccounted for. Conditions which cause this to happen include: * A flush may have attempted to update or delete rows and an unexpected number of rows were matched during the UPDATE or DELETE statement. Note that when version_id_col is used, rows in UPDATE or DELETE statements are also matched against the current known version identifier. * A mapped object with version_id_col was refreshed, and the version number coming back from the database does not match that of the object itself. * A object is detached from its parent object, however the object was previously attached to a different parent identity which was garbage collected, and a decision cannot be made if the new parent was really the most recent "parent". """ ConcurrentModificationError = StaleDataError class FlushError(sa_exc.SQLAlchemyError): """A invalid condition was detected during flush().""" class UnmappedError(sa_exc.InvalidRequestError): """Base for exceptions that involve expected mappings not present.""" class ObjectDereferencedError(sa_exc.SQLAlchemyError): """An operation cannot complete due to an object being garbage collected. """ class DetachedInstanceError(sa_exc.SQLAlchemyError): """An attempt to access unloaded attributes on a mapped instance that is detached.""" code = "bhk3" class UnmappedInstanceError(UnmappedError): """An mapping operation was requested for an unknown instance.""" @util.preload_module("sqlalchemy.orm.base") def __init__(self, obj, msg=None): base = util.preloaded.orm_base if not msg: try: base.class_mapper(type(obj)) name = _safe_cls_name(type(obj)) msg = ( "Class %r is mapped, but this instance lacks " "instrumentation. This occurs when the instance " "is created before sqlalchemy.orm.mapper(%s) " "was called." % (name, name) ) except UnmappedClassError: msg = _default_unmapped(type(obj)) if isinstance(obj, type): msg += ( "; was a class (%s) supplied where an instance was " "required?" % _safe_cls_name(obj) ) UnmappedError.__init__(self, msg) def __reduce__(self): return self.__class__, (None, self.args[0]) class UnmappedClassError(UnmappedError): """An mapping operation was requested for an unknown class.""" def __init__(self, cls, msg=None): if not msg: msg = _default_unmapped(cls) UnmappedError.__init__(self, msg) def __reduce__(self): return self.__class__, (None, self.args[0]) class ObjectDeletedError(sa_exc.InvalidRequestError): """A refresh operation failed to retrieve the database row corresponding to an object's known primary key identity. A refresh operation proceeds when an expired attribute is accessed on an object, or when :meth:`_query.Query.get` is used to retrieve an object which is, upon retrieval, detected as expired. A SELECT is emitted for the target row based on primary key; if no row is returned, this exception is raised. The true meaning of this exception is simply that no row exists for the primary key identifier associated with a persistent object. The row may have been deleted, or in some cases the primary key updated to a new value, outside of the ORM's management of the target object. """ @util.preload_module("sqlalchemy.orm.base") def __init__(self, state, msg=None): base = util.preloaded.orm_base if not msg: msg = ( "Instance '%s' has been deleted, or its " "row is otherwise not present." % base.state_str(state) ) sa_exc.InvalidRequestError.__init__(self, msg) def __reduce__(self): return self.__class__, (None, self.args[0]) class UnmappedColumnError(sa_exc.InvalidRequestError): """Mapping operation was requested on an unknown column.""" class LoaderStrategyException(sa_exc.InvalidRequestError): """A loader strategy for an attribute does not exist.""" def __init__( self, applied_to_property_type, requesting_property, applies_to, actual_strategy_type, strategy_key, ): if actual_strategy_type is None: sa_exc.InvalidRequestError.__init__( self, "Can't find strategy %s for %s" % (strategy_key, requesting_property), ) else: sa_exc.InvalidRequestError.__init__( self, 'Can\'t apply "%s" strategy to property "%s", ' 'which is a "%s"; this loader strategy is intended ' 'to be used with a "%s".' % ( util.clsname_as_plain_name(actual_strategy_type), requesting_property, util.clsname_as_plain_name(applied_to_property_type), util.clsname_as_plain_name(applies_to), ), ) def _safe_cls_name(cls): try: cls_name = ".".join((cls.__module__, cls.__name__)) except AttributeError: cls_name = getattr(cls, "__name__", None) if cls_name is None: cls_name = repr(cls) return cls_name @util.preload_module("sqlalchemy.orm.base") def _default_unmapped(cls): base = util.preloaded.orm_base try: mappers = base.manager_of_class(cls).mappers except (TypeError,) + NO_STATE: mappers = {} name = _safe_cls_name(cls) if not mappers: return "Class '%s' is not mapped" % name