warn when two classes with the same name end up in the declarative registry

2 files changed, 27 insertions, 5 deletions

diff --git a/lib/sqlalchemy/ext/declarative.py b/lib/sqlalchemy/ext/declarative.py
index 586067527..57dff857c 100755
--- a/lib/sqlalchemy/ext/declarative.py
+++ b/lib/sqlalchemy/ext/declarative.py
@@ -1046,6 +1046,13 @@ def _as_declarative(cls, classname, dict_):
     for k, v in mapper_args.iteritems():
         mapper_args[k] = column_copies.get(v,v)
     
+
+    if classname in cls._decl_class_registry:
+        util.warn("The classname %r is already in the registry of this"
+                  " declarative base, mapped to %r" % (
+                classname,
+                cls._decl_class_registry[classname]
+                ))
     cls._decl_class_registry[classname] = cls
     our_stuff = util.OrderedDict()
 
diff --git a/test/ext/test_declarative.py b/test/ext/test_declarative.py
index 0202aa69f..0a6b17e27 100644
--- a/test/ext/test_declarative.py
+++ b/test/ext/test_declarative.py
@@ -634,7 +634,7 @@ class DeclarativeTest(DeclarativeTestBase):
     def test_table_args(self):
 
         def err():
-            class Foo(Base):
+            class Foo1(Base):
 
                 __tablename__ = 'foo'
                 __table_args__ = ForeignKeyConstraint(['id'], ['foo.id'
@@ -644,13 +644,13 @@ class DeclarativeTest(DeclarativeTestBase):
         assert_raises_message(sa.exc.ArgumentError,
                               'Tuple form of __table_args__ is ', err)
 
-        class Foo(Base):
+        class Foo2(Base):
 
             __tablename__ = 'foo'
             __table_args__ = {'mysql_engine': 'InnoDB'}
             id = Column('id', Integer, primary_key=True)
 
-        assert Foo.__table__.kwargs['mysql_engine'] == 'InnoDB'
+        assert Foo2.__table__.kwargs['mysql_engine'] == 'InnoDB'
 
         class Bar(Base):
 
@@ -659,7 +659,7 @@ class DeclarativeTest(DeclarativeTestBase):
                 {'mysql_engine': 'InnoDB'}
             id = Column('id', Integer, primary_key=True)
 
-        assert Bar.__table__.c.id.references(Foo.__table__.c.id)
+        assert Bar.__table__.c.id.references(Foo2.__table__.c.id)
         assert Bar.__table__.kwargs['mysql_engine'] == 'InnoDB'
 
     def test_expression(self):
@@ -1084,6 +1084,21 @@ class DeclarativeTest(DeclarativeTestBase):
                 )).one()
         eq_(rt, u1)
 
+    @testing.emits_warning(
+        "The classname 'Test' is already in the registry "
+        "of this declarative base, mapped to "
+        "<class 'test.ext.test_declarative.Test'>"
+        )
+    def test_duplicate_classes_in_base(self):
+
+        class Test(Base):
+            __tablename__ = 'a'
+            id = Column(Integer, primary_key=True)
+
+        class Test(Base):
+            __tablename__ = 'b'
+            id = Column(Integer, primary_key=True)
+
 class DeclarativeInheritanceTest(DeclarativeTestBase):
 
     def test_we_must_copy_mapper_args(self):
@@ -3084,4 +3099,4 @@ class DeclarativeMixinPropertyTest(DeclarativeTestBase):
 
     def test_relationship_primryjoin(self):
         self._test_relationship(True)
-        
\ No newline at end of file
+