From 9b6a9b7aeab79ba28737f394fa6cfaaf1f1f1bcf Mon Sep 17 00:00:00 2001
From: Mike Bayer <mike_mp@zzzcomputing.com>
Date: Sun, 17 Aug 2008 21:55:00 +0000
Subject: [PATCH] temporary check for unmapped class, until [ticket:1142] is
 resolved

---
 lib/sqlalchemy/orm/properties.py |  4 +++-
 lib/sqlalchemy/orm/util.py       |  5 +++++
 test/orm/mapper.py               | 11 +++++++++++
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/lib/sqlalchemy/orm/properties.py b/lib/sqlalchemy/orm/properties.py
index 4056c2ff91..ebe61b19e2 100644
--- a/lib/sqlalchemy/orm/properties.py
+++ b/lib/sqlalchemy/orm/properties.py
@@ -530,7 +530,9 @@ class PropertyLoader(StrategizedProperty):
             self.mapper = mapper.class_mapper(self.argument(), compile=False)
         else:
             raise sa_exc.ArgumentError("relation '%s' expects a class or a mapper argument (received: %s)" % (self.key, type(self.argument)))
-        assert isinstance(self.mapper, mapper.Mapper), self.mapper
+
+        # TODO: an informative assertion ?
+        assert isinstance(self.mapper, mapper.Mapper)
 
         # accept callables for other attributes which may require deferred initialization
         for attr in ('order_by', 'primaryjoin', 'secondaryjoin', 'secondary', '_foreign_keys', 'remote_side'):
diff --git a/lib/sqlalchemy/orm/util.py b/lib/sqlalchemy/orm/util.py
index 928b38fd3f..4915d930d6 100644
--- a/lib/sqlalchemy/orm/util.py
+++ b/lib/sqlalchemy/orm/util.py
@@ -464,6 +464,11 @@ def class_mapper(class_, compile=True, raiseerror=True):
     try:
         class_manager = attributes.manager_of_class(class_)
         mapper = class_manager.mapper
+        
+        # HACK until [ticket:1142] is complete
+        if mapper is None:
+            raise exc.NO_STATE
+            
     except exc.NO_STATE:
         if not raiseerror:
             return
diff --git a/test/orm/mapper.py b/test/orm/mapper.py
index 73afd3b998..57bcba20ce 100644
--- a/test/orm/mapper.py
+++ b/test/orm/mapper.py
@@ -834,6 +834,17 @@ class MapperTest(_fixtures.FixtureTest):
         create_session().query(User).first()
         eq_(recon, ['go'])
 
+    @testing.resolve_artifact_names
+    def test_unmapped_error(self):
+        mapper(Address, addresses)
+        sa.orm.clear_mappers()
+        
+        mapper(User, users, properties={
+            'addresses':relation(Address)
+        })
+
+        self.assertRaises(sa.orm.exc.UnmappedClassError, sa.orm.compile_mappers)
+        
 class OptionsTest(_fixtures.FixtureTest):
 
     @testing.fails_on('maxdb')
-- 
2.47.3