Merge pull request #782 from pallets/backport-651

backport #651 fix BindMetaMixin with polymorphic

Author: davidism

CHANGES.rst

@@ -1,3 +1,12 @@
+Version 2.4.1
+-------------
+
+Unreleased
+
+-   Fix ``AttributeError`` when using multiple binds with polymorphic
+    models. :pr:`651`
+
+
 Version 2.4.0
 -------------
 

flask_sqlalchemy/model.py

@@ -120,7 +120,7 @@ def __init__(cls, name, bases, d):
 
         super(BindMetaMixin, cls).__init__(name, bases, d)
 
-        if bind_key is not None and hasattr(cls, '__table__'):
+        if bind_key is not None and getattr(cls, '__table__', None) is not None:
             cls.__table__.info['bind_key'] = bind_key
 
 

tests/test_binds.py

@@ -1,5 +1,5 @@
 import flask_sqlalchemy as fsa
-
+from sqlalchemy.ext.declarative import declared_attr
 
 def test_basic_binds(app, db):
     app.config['SQLALCHEMY_BINDS'] = {
@@ -91,3 +91,35 @@ def test_connector_cache(app):
 
     connector = fsa.get_state(app).connectors[None]
     assert connector._app is app
+
+
+def test_polymorphic_bind(app, db):
+    bind_key = 'polymorphic_bind_key'
+
+    app.config['SQLALCHEMY_BINDS'] = {
+        bind_key: 'sqlite:///:memory',
+    }
+
+    class Base(db.Model):
+        __bind_key__ = bind_key
+
+        __tablename__ = 'base'
+
+        id = db.Column(db.Integer, primary_key=True)
+
+        p_type = db.Column(db.String(50))
+
+        __mapper_args__ = {
+            'polymorphic_identity': 'base',
+            'polymorphic_on': p_type
+        }
+
+    class Child1(Base):
+
+        child_1_data = db.Column(db.String(50))
+        __mapper_args__ = {
+            'polymorphic_identity': 'child_1',
+        }
+
+    assert Base.__table__.info['bind_key'] == bind_key
+    assert Child1.__table__.info['bind_key'] == bind_key