From 5a10b6a455f9ad7be752469cbaa503857ae9fda2 Mon Sep 17 00:00:00 2001
From: Mike Bayer <mike_mp@zzzcomputing.com>
Date: Mon, 6 Oct 2014 18:33:05 -0400
Subject: [PATCH] - Fixed "'NoneType' object has no attribute 'concrete'" error
 when using :class:`.AbstractConcreteBase` in conjunction with a subclass that
 declares ``__abstract__``. fixes #3185

---
 doc/build/changelog/changelog_09.rst     |  9 ++++++++
 lib/sqlalchemy/ext/declarative/api.py    |  2 +-
 test/ext/declarative/test_inheritance.py | 29 ++++++++++++++++++++++++
 3 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/doc/build/changelog/changelog_09.rst b/doc/build/changelog/changelog_09.rst
index 7dd50739e0..692c6e3925 100644
--- a/doc/build/changelog/changelog_09.rst
+++ b/doc/build/changelog/changelog_09.rst
@@ -13,6 +13,15 @@
 .. changelog::
     :version: 0.9.8
 
+    .. change::
+        :tags: bug, declarative, orm
+        :versions: 1.0.0
+        :tickets: 3185
+
+        Fixed "'NoneType' object has no attribute 'concrete'" error
+        when using :class:`.AbstractConcreteBase` in conjunction with
+        a subclass that declares ``__abstract__``.
+
     .. change::
         :tags: bug, engine
         :versions: 1.0.0
diff --git a/lib/sqlalchemy/ext/declarative/api.py b/lib/sqlalchemy/ext/declarative/api.py
index e84b21ad23..66fe05fd0e 100644
--- a/lib/sqlalchemy/ext/declarative/api.py
+++ b/lib/sqlalchemy/ext/declarative/api.py
@@ -547,7 +547,7 @@ class AbstractConcreteBase(ConcreteBase):
 
         for scls in cls.__subclasses__():
             sm = _mapper_or_none(scls)
-            if sm.concrete and cls in scls.__bases__:
+            if sm and sm.concrete and cls in scls.__bases__:
                 sm._set_concrete_base(m)
 
 
diff --git a/test/ext/declarative/test_inheritance.py b/test/ext/declarative/test_inheritance.py
index 5a99c9c5a7..6ea37e4d3b 100644
--- a/test/ext/declarative/test_inheritance.py
+++ b/test/ext/declarative/test_inheritance.py
@@ -1388,3 +1388,32 @@ class ConcreteExtensionConfigTest(
             "WHERE something.id = pjoin.something_id AND something.id = :id_1)"
         )
 
+    def test_abstract_in_hierarchy(self):
+        class Document(Base, AbstractConcreteBase):
+            doctype = Column(String)
+
+        class ContactDocument(Document):
+            __abstract__ = True
+
+            send_method = Column(String)
+
+        class ActualDocument(ContactDocument):
+            __tablename__ = 'actual_documents'
+            __mapper_args__ = {
+                'concrete': True,
+                'polymorphic_identity': 'actual'}
+
+            id = Column(Integer, primary_key=True)
+
+        configure_mappers()
+        session = Session()
+        self.assert_compile(
+            session.query(Document),
+            "SELECT pjoin.doctype AS pjoin_doctype, "
+            "pjoin.send_method AS pjoin_send_method, "
+            "pjoin.id AS pjoin_id, pjoin.type AS pjoin_type "
+            "FROM (SELECT actual_documents.doctype AS doctype, "
+            "actual_documents.send_method AS send_method, "
+            "actual_documents.id AS id, 'actual' AS type "
+            "FROM actual_documents) AS pjoin"
+        )
\ No newline at end of file
-- 
2.47.2