Merge "Disable and disallow Result.unique() with yield_per"

2 files changed, 14 insertions, 2 deletions

diff --git a/lib/sqlalchemy/orm/loading.py b/lib/sqlalchemy/orm/loading.py
index 4a90caeff..9dcaca0ea 100644
--- a/lib/sqlalchemy/orm/loading.py
+++ b/lib/sqlalchemy/orm/loading.py
@@ -87,11 +87,20 @@ def instances(cursor, context):
         with util.safe_reraise():
             cursor.close()
 
+    def _no_unique(entry):
+        raise sa_exc.InvalidRequestError(
+            "Can't use the ORM yield_per feature in conjunction with unique()"
+        )
+
     row_metadata = SimpleResultMetaData(
         labels,
         extra,
         _unique_filters=[
-            id if ent.use_id_for_hash else None
+            _no_unique
+            if context.yield_per
+            else id
+            if ent.use_id_for_hash
+            else None
             for ent in context.compile_state._entities
         ],
     )
diff --git a/lib/sqlalchemy/orm/query.py b/lib/sqlalchemy/orm/query.py
index 38f1d26b4..9348d7d48 100644
--- a/lib/sqlalchemy/orm/query.py
+++ b/lib/sqlalchemy/orm/query.py
@@ -2827,7 +2827,10 @@ class Query(
         if result._attributes.get("is_single_entity", False):
             result = result.scalars()
 
-        if result._attributes.get("filtered", False):
+        if (
+            result._attributes.get("filtered", False)
+            and not self.load_options._yield_per
+        ):
             result = result.unique()
 
         return result