From: Mike Bayer <mike_mp@zzzcomputing.com>
Date: Thu, 12 Jun 2008 03:34:13 +0000 (+0000)
Subject: - the enable_typechecks=False setting on relation()
X-Git-Tag: rel_0_4_7~20
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=ff364b9c54715be82180c62bf9d5db0ea4b047e3;p=thirdparty%2Fsqlalchemy%2Fsqlalchemy.git

- the enable_typechecks=False setting on relation()
now only allows subtypes with inheriting mappers.
Totally unrelated types, or subtypes not set up with
mapper inheritance against the target mapper are
still not allowed.
---

diff --git a/CHANGES b/CHANGES
index ec85febbb5..7f9d208b9e 100644
--- a/CHANGES
+++ b/CHANGES
@@ -15,6 +15,12 @@ CHANGES
     - Query.count() will take single-table inheritance
       subtypes into account the same way row-based
       results do. [ticket:1008]
+
+    - the enable_typechecks=False setting on relation()
+      now only allows subtypes with inheriting mappers.  
+      Totally unrelated types, or subtypes not set up with
+      mapper inheritance against the target mapper are 
+      still not allowed.
       
 - mysql
     - Added 'CALL' to the list of SQL keywords which return
diff --git a/lib/sqlalchemy/orm/dependency.py b/lib/sqlalchemy/orm/dependency.py
index c667460a71..c16bd8bbd0 100644
--- a/lib/sqlalchemy/orm/dependency.py
+++ b/lib/sqlalchemy/orm/dependency.py
@@ -108,11 +108,12 @@ class DependencyProcessor(object):
         raise NotImplementedError()
 
     def _verify_canload(self, state):
-        if not self.enable_typechecks:
-            return
-        if state is not None and not self.mapper._canload(state):
-            raise exceptions.FlushError("Attempting to flush an item of type %s on collection '%s', which is handled by mapper '%s' and does not load items of that type.  Did you mean to use a polymorphic mapper for this relationship ?  Set 'enable_typechecks=False' on the relation() to disable this exception.  Mismatched typeloading may cause bi-directional relationships (backrefs) to not function properly." % (state.class_, self.prop, self.mapper))
-
+        if state is not None and not self.mapper._canload(state, allow_subtypes=not self.enable_typechecks):
+            if self.mapper._canload(state, allow_subtypes=True):
+                raise exceptions.FlushError("Attempting to flush an item of type %s on collection '%s', which is not the expected type %s.  Configure mapper '%s' to load this subtype polymorphically, or set enable_typechecks=False to allow subtypes.  Mismatched typeloading may cause bi-directional relationships (backrefs) to not function properly." % (state.class_, self.prop, self.mapper.class_, self.mapper))
+            else:
+                raise exceptions.FlushError("Attempting to flush an item of type %s on collection '%s', whose mapper does not inherit from that of %s." % (state.class_, self.prop, self.mapper.class_))
+            
     def _synchronize(self, state, child, associationrow, clearkeys, uowcommit):
         """Called during a flush to synchronize primary key identifier
         values between a parent/child object, as well as to an
diff --git a/lib/sqlalchemy/orm/mapper.py b/lib/sqlalchemy/orm/mapper.py
index 448d797d06..d39e743e01 100644
--- a/lib/sqlalchemy/orm/mapper.py
+++ b/lib/sqlalchemy/orm/mapper.py
@@ -945,9 +945,9 @@ class Mapper(object):
     def _primary_key_from_state(self, state):
         return [self._get_state_attr_by_column(state, column) for column in self.primary_key]
 
-    def _canload(self, state):
-        if self.polymorphic_on:
-            return issubclass(state.class_, self.class_)
+    def _canload(self, state, allow_subtypes):
+        if self.polymorphic_on or allow_subtypes:
+            return self.isa(_state_mapper(state))
         else:
             return state.class_ is self.class_
 
diff --git a/test/orm/relationships.py b/test/orm/relationships.py
index 40773f8359..de3028903e 100644
--- a/test/orm/relationships.py
+++ b/test/orm/relationships.py
@@ -646,11 +646,8 @@ class TypeMatchTest(ORMTest):
         sess.save(a1)
         sess.save(b1)
         sess.save(c1)
-        try:
-            sess.flush()
-            assert False
-        except exceptions.FlushError, err:
-            assert str(err).startswith("Attempting to flush an item of type %s on collection 'A.bs (B)', which is handled by mapper 'Mapper|B|b' and does not load items of that type.  Did you mean to use a polymorphic mapper for this relationship ?" % C)
+        self.assertRaises(exceptions.FlushError, sess.flush)
+
     def test_o2m_nopoly_onflush(self):
         class A(object):pass
         class B(object):pass
@@ -668,11 +665,7 @@ class TypeMatchTest(ORMTest):
         sess.save(a1)
         sess.save(b1)
         sess.save(c1)
-        try:
-            sess.flush()
-            assert False
-        except exceptions.FlushError, err:
-            assert str(err).startswith("Attempting to flush an item of type %s on collection 'A.bs (B)', which is handled by mapper 'Mapper|B|b' and does not load items of that type.  Did you mean to use a polymorphic mapper for this relationship ?" % C)
+        self.assertRaises(exceptions.FlushError, sess.flush)
 
     def test_m2o_nopoly_onflush(self):
         class A(object):pass
@@ -687,11 +680,8 @@ class TypeMatchTest(ORMTest):
         sess = create_session()
         sess.save(b1)
         sess.save(d1)
-        try:
-            sess.flush()
-            assert False
-        except exceptions.FlushError, err:
-            assert str(err).startswith("Attempting to flush an item of type %s on collection 'D.a (A)', which is handled by mapper 'Mapper|A|a' and does not load items of that type.  Did you mean to use a polymorphic mapper for this relationship ?" % B)
+        self.assertRaises(exceptions.FlushError, sess.flush)
+
     def test_m2o_oncascade(self):
         class A(object):pass
         class B(object):pass
@@ -703,6 +693,7 @@ class TypeMatchTest(ORMTest):
         d1 = D()
         d1.a = b1
         sess = create_session()
+
         try:
             sess.save(d1)
             assert False