- Made a small adjustment to the mechanics of lazy loading,

such that it has less chance of interfering with a joinload() in the
very rare circumstance that an object points to itself; in this
scenario, the object refers to itself while loading its attributes
which can cause a mixup between loaders.   The use case of
"object points to itself" is not fully supported, but the fix also
removes some overhead so for now is part of testing.
fixes #3145

2 files changed, 7 insertions, 2 deletions

diff --git a/lib/sqlalchemy/orm/strategies.py b/lib/sqlalchemy/orm/strategies.py
index c3edbf6e6..2d8a81f0a 100644
--- a/lib/sqlalchemy/orm/strategies.py
+++ b/lib/sqlalchemy/orm/strategies.py
@@ -634,7 +634,7 @@ class LazyLoader(AbstractRelationshipLoader):
                 LoadLazyAttribute(key), key)
 
             return set_lazy_callable, None, None
-        else:
+        elif context.populate_existing or mapper.always_refresh:
             def reset_for_lazy_callable(state, dict_, row):
                 # we are the primary manager for this attribute on
                 # this class - reset its
@@ -647,6 +647,9 @@ class LazyLoader(AbstractRelationshipLoader):
                 state._reset(dict_, key)
 
             return reset_for_lazy_callable, None, None
+        else:
+            return None, None, None
+
 
 
 class LoadLazyAttribute(object):
diff --git a/lib/sqlalchemy/testing/util.py b/lib/sqlalchemy/testing/util.py
index fc8390a79..7b3f721a6 100644
--- a/lib/sqlalchemy/testing/util.py
+++ b/lib/sqlalchemy/testing/util.py
@@ -203,5 +203,7 @@ class adict(dict):
         except KeyError:
             return dict.__getattribute__(self, key)
 
-    def get_all(self, *keys):
+    def __call__(self, *keys):
         return tuple([self[key] for key in keys])
+
+    get_all = __call__