From 75a3f84e5f9c3be645be2ec8906e63b27e9847e5 Mon Sep 17 00:00:00 2001 From: Mike Bayer Date: Sun, 3 Mar 2013 13:51:54 -0500 Subject: [PATCH] - Improved checking for an existing backref name conflict during mapper configuration; will now test for name conflicts on superclasses and subclasses, in addition to the current mapper, as these conflicts break things just as much. This is new for 0.8, but see below for a warning that will also be triggered in 0.7.11. - Improved the error message emitted when a "backref loop" is detected, that is when an attribute event triggers a bidirectional assignment between two other attributes with no end. This condition can occur not just when an object of the wrong type is assigned, but also when an attribute is mis-configured to backref into an existing backref pair. Also in 0.7.11. - A warning is emitted when a MapperProperty is assigned to a mapper that replaces an existing property, if the properties in question aren't plain column-based properties. Replacement of relationship properties is rarely (ever?) what is intended and usually refers to a mapper mis-configuration. Also in 0.7.11. [ticket:2674] --- doc/build/changelog/changelog_07.rst | 23 ++++++++++++++++ doc/build/changelog/changelog_08.rst | 32 ++++++++++++++++++++++ lib/sqlalchemy/orm/attributes.py | 24 ++++++++++++---- lib/sqlalchemy/orm/mapper.py | 12 +++++++- lib/sqlalchemy/orm/properties.py | 19 +++++++++---- test/orm/test_attributes.py | 41 ++++++++++++++++++++++++++-- test/orm/test_compile.py | 32 ++++++++++++++++++++-- test/orm/test_mapper.py | 20 +++++++++++++- 8 files changed, 185 insertions(+), 18 deletions(-) diff --git a/doc/build/changelog/changelog_07.rst b/doc/build/changelog/changelog_07.rst index 41aac067b1..df919dc3d9 100644 --- a/doc/build/changelog/changelog_07.rst +++ b/doc/build/changelog/changelog_07.rst @@ -14,6 +14,29 @@ Fixed an import of "logging" in test_execute which was not working on some linux platforms. + .. change:: + :tags: bug, orm + :tickets: 2674 + + Improved the error message emitted when a "backref loop" is detected, + that is when an attribute event triggers a bidirectional + assignment between two other attributes with no end. + This condition can occur not just when an object of the wrong + type is assigned, but also when an attribute is mis-configured + to backref into an existing backref pair. + + .. change:: + :tags: bug, orm + :tickets: 2674 + + A warning is emitted when a MapperProperty is assigned to a mapper + that replaces an existing property, if the properties in question + aren't plain column-based properties. Replacement of relationship + properties is rarely (ever?) what is intended and usually refers to a + mapper mis-configuration. This will also warn if a backref configures + itself on top of an existing one in an inheritance relationship + (which is an error in 0.8). + .. changelog:: :version: 0.7.10 :released: Thu Feb 7 2013 diff --git a/doc/build/changelog/changelog_08.rst b/doc/build/changelog/changelog_08.rst index 370de26039..59f2b3ad13 100644 --- a/doc/build/changelog/changelog_08.rst +++ b/doc/build/changelog/changelog_08.rst @@ -16,6 +16,38 @@ * :ref:`metadata_create_drop_tables` + .. change:: + :tags: bug, orm + :tickets: 2674 + + Improved checking for an existing backref name conflict during + mapper configuration; will now test for name conflicts on + superclasses and subclasses, in addition to the current mapper, + as these conflicts break things just as much. This is new for + 0.8, but see below for a warning that will also be triggered + in 0.7.11. + + .. change:: + :tags: bug, orm + :tickets: 2674 + + Improved the error message emitted when a "backref loop" is detected, + that is when an attribute event triggers a bidirectional + assignment between two other attributes with no end. + This condition can occur not just when an object of the wrong + type is assigned, but also when an attribute is mis-configured + to backref into an existing backref pair. Also in 0.7.11. + + .. change:: + :tags: bug, orm + :tickets: 2674 + + A warning is emitted when a MapperProperty is assigned to a mapper + that replaces an existing property, if the properties in question + aren't plain column-based properties. Replacement of relationship + properties is rarely (ever?) what is intended and usually refers to a + mapper mis-configuration. Also in 0.7.11. + .. change:: :tags: feature, orm diff --git a/lib/sqlalchemy/orm/attributes.py b/lib/sqlalchemy/orm/attributes.py index c9385daaaf..b281fabec4 100644 --- a/lib/sqlalchemy/orm/attributes.py +++ b/lib/sqlalchemy/orm/attributes.py @@ -433,6 +433,9 @@ class AttributeImpl(object): self.expire_missing = expire_missing + def __str__(self): + return "%s.%s" % (self.class_.__name__, self.key) + def _get_active_history(self): """Backwards compat for impl.active_history""" @@ -1043,11 +1046,18 @@ def backref_listeners(attribute, key, uselist): parent_token = attribute.impl.parent_token - def _acceptable_key_err(child_state, initiator): + def _acceptable_key_err(child_state, initiator, child_impl): raise ValueError( - "Object %s not associated with attribute of " - "type %s" % (orm_util.state_str(child_state), - manager_of_class(initiator.class_)[initiator.key])) + "Bidirectional attribute conflict detected: " + 'Passing object %s to attribute "%s" ' + 'triggers a modify event on attribute "%s" ' + 'via the backref "%s".' % ( + orm_util.state_str(child_state), + initiator.parent_token, + child_impl.parent_token, + attribute.impl.parent_token + ) + ) def emit_backref_from_scalar_set_event(state, child, oldchild, initiator): if oldchild is child: @@ -1069,7 +1079,7 @@ def backref_listeners(attribute, key, uselist): child_impl = child_state.manager[key].impl if initiator.parent_token is not parent_token and \ initiator.parent_token is not child_impl.parent_token: - _acceptable_key_err(state, initiator) + _acceptable_key_err(state, initiator, child_impl) child_impl.append( child_state, child_dict, @@ -1085,9 +1095,11 @@ def backref_listeners(attribute, key, uselist): child_state, child_dict = instance_state(child), \ instance_dict(child) child_impl = child_state.manager[key].impl + + print initiator.parent_token, parent_token, child_impl.parent_token if initiator.parent_token is not parent_token and \ initiator.parent_token is not child_impl.parent_token: - _acceptable_key_err(state, initiator) + _acceptable_key_err(state, initiator, child_impl) child_impl.append( child_state, child_dict, diff --git a/lib/sqlalchemy/orm/mapper.py b/lib/sqlalchemy/orm/mapper.py index 447a5fce12..4e7b4d272b 100644 --- a/lib/sqlalchemy/orm/mapper.py +++ b/lib/sqlalchemy/orm/mapper.py @@ -1094,7 +1094,7 @@ class Mapper(_InspectionAttr): # initialized; check for 'readonly' if hasattr(self, '_readonly_props') and \ (not hasattr(col, 'table') or - col.table not in self._cols_by_table): + col.table not in self._cols_by_table): self._readonly_props.add(prop) else: @@ -1132,6 +1132,16 @@ class Mapper(_InspectionAttr): "%r for column %r" % (syn, key, key, syn) ) + if key in self._props and \ + not isinstance(prop, properties.ColumnProperty) and \ + not isinstance(self._props[key], properties.ColumnProperty): + util.warn("Property %s on %s being replaced with new " + "property %s; the old property will be discarded" % ( + self._props[key], + self, + prop, + )) + self._props[key] = prop if not self.non_primary: diff --git a/lib/sqlalchemy/orm/properties.py b/lib/sqlalchemy/orm/properties.py index a0d8c92d1a..79a1b81d36 100644 --- a/lib/sqlalchemy/orm/properties.py +++ b/lib/sqlalchemy/orm/properties.py @@ -816,7 +816,10 @@ class RelationshipProperty(StrategizedProperty): adapt_source=adapt_source) def __str__(self): - return str(self.parent.class_.__name__) + "." + self.key + if self.parent: + return str(self.parent.class_.__name__) + "." + self.key + else: + return "." + self.key def merge(self, session, @@ -1201,11 +1204,15 @@ class RelationshipProperty(StrategizedProperty): else: backref_key, kwargs = self.backref mapper = self.mapper.primary_mapper() - if mapper.has_property(backref_key): - raise sa_exc.ArgumentError("Error creating backref " - "'%s' on relationship '%s': property of that " - "name exists on mapper '%s'" % (backref_key, - self, mapper)) + + check = set(mapper.iterate_to_root()).\ + union(mapper.self_and_descendants) + for m in check: + if m.has_property(backref_key): + raise sa_exc.ArgumentError("Error creating backref " + "'%s' on relationship '%s': property of that " + "name exists on mapper '%s'" % (backref_key, + self, m)) # determine primaryjoin/secondaryjoin for the # backref. Use the one we had, so that diff --git a/test/orm/test_attributes.py b/test/orm/test_attributes.py index 1fc70fd77b..d60c55edd2 100644 --- a/test/orm/test_attributes.py +++ b/test/orm/test_attributes.py @@ -1170,7 +1170,10 @@ class CyclicBackrefAssertionTest(fixtures.TestBase): b1 = B() assert_raises_message( ValueError, - "Object not associated with attribute of type C.a", + 'Bidirectional attribute conflict detected: ' + 'Passing object to attribute "C.a" ' + 'triggers a modify event on attribute "C.b" ' + 'via the backref "B.c".', setattr, c1, 'a', b1 ) @@ -1180,10 +1183,14 @@ class CyclicBackrefAssertionTest(fixtures.TestBase): b1 = B() assert_raises_message( ValueError, - "Object not associated with attribute of type C.a", + 'Bidirectional attribute conflict detected: ' + 'Passing object to attribute "C.a" ' + 'triggers a modify event on attribute "C.b" ' + 'via the backref "B.c".', c1.a.append, b1 ) + def _scalar_fixture(self): class A(object): pass @@ -1225,6 +1232,36 @@ class CyclicBackrefAssertionTest(fixtures.TestBase): return A, B, C + def _broken_collection_fixture(self): + class A(object): + pass + class B(object): + pass + instrumentation.register_class(A) + instrumentation.register_class(B) + + attributes.register_attribute(A, 'b', backref='a1', useobject=True) + attributes.register_attribute(B, 'a1', backref='b', useobject=True, + uselist=True) + + attributes.register_attribute(B, 'a2', backref='b', useobject=True, + uselist=True) + + return A, B + + def test_broken_collection_assertion(self): + A, B = self._broken_collection_fixture() + b1 = B() + a1 = A() + assert_raises_message( + ValueError, + 'Bidirectional attribute conflict detected: ' + 'Passing object to attribute "B.a2" ' + 'triggers a modify event on attribute "B.a1" ' + 'via the backref "A.b".', + b1.a2.append, a1 + ) + class PendingBackrefTest(fixtures.ORMTest): def setup(self): global Post, Blog, called, lazy_load diff --git a/test/orm/test_compile.py b/test/orm/test_compile.py index fb32fb0b9b..ad6778e97a 100644 --- a/test/orm/test_compile.py +++ b/test/orm/test_compile.py @@ -167,8 +167,10 @@ class CompileTest(fixtures.ORMTest): b = Table('b', meta, Column('id', Integer, primary_key=True), Column('a_id', Integer, ForeignKey('a.id'))) - class A(object):pass - class B(object):pass + class A(object): + pass + class B(object): + pass mapper(A, a, properties={ 'b':relationship(B, backref='a') @@ -183,3 +185,29 @@ class CompileTest(fixtures.ORMTest): configure_mappers ) + def test_conflicting_backref_subclass(self): + meta = MetaData() + + a = Table('a', meta, Column('id', Integer, primary_key=True)) + b = Table('b', meta, Column('id', Integer, primary_key=True), + Column('a_id', Integer, ForeignKey('a.id'))) + + class A(object): + pass + class B(object): + pass + class C(B): + pass + + mapper(A, a, properties={ + 'b': relationship(B, backref='a'), + 'c': relationship(C, backref='a') + }) + mapper(B, b) + mapper(C, None, inherits=B) + + assert_raises_message( + sa_exc.ArgumentError, + "Error creating backref", + configure_mappers + ) diff --git a/test/orm/test_mapper.py b/test/orm/test_mapper.py index 8c5b9cd849..66082b5494 100644 --- a/test/orm/test_mapper.py +++ b/test/orm/test_mapper.py @@ -488,7 +488,7 @@ class MapperTest(_fixtures.FixtureTest, AssertsCompiledSQL): assert hasattr(User, 'addresses') assert "addresses" in [p.key for p in m1._polymorphic_properties] - def test_replace_property(self): + def test_replace_col_prop_w_syn(self): users, User = self.tables.users, self.classes.User m = mapper(User, users) @@ -514,6 +514,24 @@ class MapperTest(_fixtures.FixtureTest, AssertsCompiledSQL): u.name = 'jacko' assert m._columntoproperty[users.c.name] is m.get_property('_name') + def test_replace_rel_prop_with_rel_warns(self): + users, User = self.tables.users, self.classes.User + addresses, Address = self.tables.addresses, self.classes.Address + + m = mapper(User, users, properties={ + "addresses": relationship(Address) + }) + mapper(Address, addresses) + + assert_raises_message( + sa.exc.SAWarning, + "Property User.addresses on Mapper|User|users being replaced " + "with new property User.addresses; the old property will " + "be discarded", + m.add_property, + "addresses", relationship(Address) + ) + def test_add_column_prop_deannotate(self): User, users = self.classes.User, self.tables.users Address, addresses = self.classes.Address, self.tables.addresses -- 2.47.2