More tests for attr observers

sqlalchemy_utils/decorators.py

@@ -90,40 +90,42 @@ class AttributeValueGenerator(object):
                 )
             elif index == len(path) - 1:
                 inversed_path = ~path[0:-1]
-                entities = list(
-                    getdotattr(
-                        target,
-                        str(inversed_path)
-                    )
+                entities = getdotattr(
+                    target,
+                    str(inversed_path)
                 )
-                for entity in entities:
-                    if isinstance(entity, list):
-                        for e in entity:
+                if entities:
+                    if not isinstance(entities, list):
+                        entities = [entities]
+                    for entity in entities:
+                        if isinstance(entity, list):
+                            for e in entity:
+                                setattr(
+                                    e,
+                                    property_key,
+                                    value
+                                )
+                        else:
                             setattr(
-                                e,
+                                entity,
                                 property_key,
                                 value
                             )
-                    else:
+            else:
+                inversed_path = ~path[0:-1]
+                entities = getdotattr(
+                    target,
+                    str(inversed_path[index:])
+                )
+                if entities:
+                    if not isinstance(entities, list):
+                        entities = [entities]
+                    for entity in entities:
                         setattr(
                             entity,
                             property_key,
-                            value
+                            getdotattr(value, str(path[(index + 1):]))
                         )
-            else:
-                inversed_path = ~path[0:-1]
-                entities = list(
-                    getdotattr(
-                        target,
-                        str(inversed_path[index:])
-                    )
-                )
-                for entity in entities:
-                    setattr(
-                        entity,
-                        property_key,
-                        getdotattr(value, str(path[(index + 1):]))
-                    )
 
 
     def update_generated_properties(self, session, ctx, instances):

sqlalchemy_utils/functions/orm.py

@@ -251,6 +251,8 @@ def getdotattr(obj_or_class, dot_path):
             last = tmp
         elif isinstance(last, InstrumentedAttribute):
             last = getter(last.property.mapper.class_)
+        elif last is None:
+            return None
         else:
             last = getter(last)
     return last

sqlalchemy_utils/path.py

@@ -85,7 +85,10 @@ class AttrPath(object):
                         prop.parent.class_.__name__
                     )
                 )
-            return backref
+            if isinstance(backref, tuple):
+                return backref[0]
+            else:
+                return backref
 
         if isinstance(self.parts[-1].property, sa.orm.ColumnProperty):
             class_ = self.parts[-1].class_

tests/test_generates.py

@@ -170,9 +170,86 @@ class TestInstantAttributeValueGeneration(TestCase):
         document = self.Document(name=u'Document 1', locale='en')
         section = self.Section(name=u'Section 1', document=document)
         subsection = self.SubSection(name=u'Section 1', section=section)
-        assert subsection.locale == 'en'
         document.locale = 'fi'
         assert subsection.locale == 'fi'
+
+    def test_simple_assignment(self):
+        document = self.Document(name=u'Document 1', locale='en')
+        section = self.Section(name=u'Section 1', document=document)
+        subsection = self.SubSection(name=u'Section 1', section=section)
+        assert subsection.locale == 'en'
+
+    def test_intermediate_object_reference(self):
+        document = self.Document(name=u'Document 1', locale='en')
+        section = self.Section(name=u'Section 1', document=document)
+        subsection = self.SubSection(name=u'Section 1', section=section)
         section.document = self.Document(name=u'Document 2', locale='sv')
         assert subsection.locale == 'sv'
 
+
+class TestInstantAttrGenerationWithScalars(TestCase):
+    def create_models(self):
+        class Document(self.Base):
+            __tablename__ = 'document'
+            id = sa.Column(sa.Integer, primary_key=True)
+            name = sa.Column(sa.Unicode(255))
+            locale = sa.Column(sa.String(10))
+
+        class Section(self.Base):
+            __tablename__ = 'section'
+            id = sa.Column(sa.Integer, primary_key=True)
+            name = sa.Column(sa.Unicode(255))
+            locale = sa.Column(sa.String(10))
+
+            document_id = sa.Column(
+                sa.Integer, sa.ForeignKey(Document.id)
+            )
+
+            document = sa.orm.relationship(
+                Document,
+                backref=sa.orm.backref('section', uselist=False)
+            )
+
+        class SubSection(self.Base):
+            __tablename__ = 'subsection'
+            id = sa.Column(sa.Integer, primary_key=True)
+            name = sa.Column(sa.Unicode(255))
+            locale = sa.Column(sa.String(10))
+
+            section_id = sa.Column(
+                sa.Integer, sa.ForeignKey(Section.id)
+            )
+
+            section = sa.orm.relationship(
+                Section,
+                backref=sa.orm.backref('subsection', uselist=False)
+            )
+
+            @generates(locale, source='section.document.locale')
+            def copy_locale(self, value):
+                return value
+
+
+        self.Document = Document
+        self.Section = Section
+        self.SubSection = SubSection
+
+    def test_change_parent_attribute(self):
+        document = self.Document(name=u'Document 1', locale='en')
+        section = self.Section(name=u'Section 1', document=document)
+        subsection = self.SubSection(name=u'Section 1', section=section)
+        document.locale = 'fi'
+        assert subsection.locale == 'fi'
+
+    def test_simple_assignment(self):
+        document = self.Document(name=u'Document 1', locale='en')
+        section = self.Section(name=u'Section 1', document=document)
+        subsection = self.SubSection(name=u'Section 1', section=section)
+        assert subsection.locale == 'en'
+
+    def test_intermediate_object_reference(self):
+        document = self.Document(name=u'Document 1', locale='en')
+        section = self.Section(name=u'Section 1', document=document)
+        subsection = self.SubSection(name=u'Section 1', section=section)
+        section.document = self.Document(name=u'Document 2', locale='sv')
+        assert subsection.locale == 'sv'