Updated SqlAlchemy

sqlalchemy/orm/exc.py

@@ -1,42 +1,79 @@
-# exc.py - ORM exceptions
-# Copyright (C) the SQLAlchemy authors and contributors
+# orm/exc.py
+# Copyright (C) 2005-2017 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
 #
 # This module is part of SQLAlchemy and is released under
 # the MIT License: http://www.opensource.org/licenses/mit-license.php
 
 """SQLAlchemy ORM exceptions."""
-
-import sqlalchemy as sa
-
+from .. import exc as sa_exc, util
 
 NO_STATE = (AttributeError, KeyError)
 """Exception types that may be raised by instrumentation implementations."""
 
-class ConcurrentModificationError(sa.exc.SQLAlchemyError):
-    """Rows have been modified outside of the unit of work."""
+
+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".
+
+      .. versionadded:: 0.7.4
+
+    """
+
+ConcurrentModificationError = StaleDataError
 
 
-class FlushError(sa.exc.SQLAlchemyError):
+class FlushError(sa_exc.SQLAlchemyError):
     """A invalid condition was detected during flush()."""
 
 
-class UnmappedError(sa.exc.InvalidRequestError):
-    """TODO"""
+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."""
+
 
-class DetachedInstanceError(sa.exc.SQLAlchemyError):
-    """An attempt to access unloaded attributes on a mapped instance that is detached."""
-    
 class UnmappedInstanceError(UnmappedError):
     """An mapping operation was requested for an unknown instance."""
 
-    def __init__(self, obj, msg=None):
+    @util.dependencies("sqlalchemy.orm.base")
+    def __init__(self, base, obj, msg=None):
         if not msg:
             try:
-                mapper = sa.orm.class_mapper(type(obj))
+                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))
+                       "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):
@@ -45,6 +82,9 @@ class UnmappedInstanceError(UnmappedError):
                         '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."""
@@ -54,28 +94,53 @@ class UnmappedClassError(UnmappedError):
             msg = _default_unmapped(cls)
         UnmappedError.__init__(self, msg)
 
-
-class ObjectDeletedError(sa.exc.InvalidRequestError):
-    """An refresh() operation failed to re-retrieve an object's row."""
+    def __reduce__(self):
+        return self.__class__, (None, self.args[0])
 
 
-class UnmappedColumnError(sa.exc.InvalidRequestError):
+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.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.dependencies("sqlalchemy.orm.base")
+    def __init__(self, base, state, msg=None):
+        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 NoResultFound(sa.exc.InvalidRequestError):
+class NoResultFound(sa_exc.InvalidRequestError):
     """A database result was required but none was found."""
 
 
-class MultipleResultsFound(sa.exc.InvalidRequestError):
+class MultipleResultsFound(sa_exc.InvalidRequestError):
     """A single database result was required but more than one were found."""
 
 
-# Legacy compat until 0.6.
-sa.exc.ConcurrentModificationError = ConcurrentModificationError
-sa.exc.FlushError = FlushError
-sa.exc.UnmappedColumnError
-
 def _safe_cls_name(cls):
     try:
         cls_name = '.'.join((cls.__module__, cls.__name__))
@@ -85,9 +150,11 @@ def _safe_cls_name(cls):
             cls_name = repr(cls)
     return cls_name
 
-def _default_unmapped(cls):
+
+@util.dependencies("sqlalchemy.orm.base")
+def _default_unmapped(base, cls):
     try:
-        mappers = sa.orm.attributes.manager_of_class(cls).mappers
+        mappers = base.manager_of_class(cls).mappers
     except NO_STATE:
         mappers = {}
     except TypeError: