not joining already eager loaded models

HISTORY.rst

@@ -3,6 +3,12 @@
 History
 -------
 
+0.3.8 (2018-08-08)
+~~~~~~~~~~~~~~~~~~
+
+* Fixed ``SQLAlchemyFilterBackend`` by not joining nested models
+  when they are already eager loaded via ``query.options()``.
+
 0.3.7 (2018-07-27)
 ~~~~~~~~~~~~~~~~~~
 

tests/backends/test_sqlalchemy.py

@@ -5,6 +5,7 @@
 import six
 from alchemy_mock.comparison import ExpressionMatcher
 from sqlalchemy import func
+from sqlalchemy.orm import joinedload
 from sqlalchemy.types import String
 
 from test_project.one_to_one.alchemy import Place, Restaurant, Waiter
@@ -75,6 +76,20 @@ def test_filter(self, alchemy_db):
             '\nWHERE one_to_one_waiter.name ={}'.format(sql.rsplit('=', 1)[-1])
         )
 
+    def test_filter_already_eagerloaded(self, alchemy_db):
+        backend = SQLAlchemyFilterBackend(
+            alchemy_db.query(Place).options(joinedload(Place.restaurant).joinedload(Restaurant.waiter_set)),
+        )
+        backend.bind([
+            FilterSpec(['restaurant', 'waiter_set', 'name'], 'exact', 'John', False),
+        ])
+
+        filtered = backend.filter()
+
+        sql = six.text_type(filtered)
+        assert 'place JOIN one_to_one' not in sql
+        assert 'place LEFT OUTER JOIN one_to_one' in sql
+
     def _test_build_clause(self, alchemy_db, name, lookup, value, expected, is_negated=False):
         backend = SQLAlchemyFilterBackend(
             alchemy_db.query(Place),

url_filter/__init__.py

@@ -4,4 +4,4 @@
 
 __author__ = 'Miroslav Shubernetskiy'
 __email__ = '[email protected]'
-__version__ = '0.3.7'
+__version__ = '0.3.8'

url_filter/backends/sqlalchemy.py

@@ -127,6 +127,10 @@ def build_clause(self, spec):
             else:
                 to_join.append(_field)
 
+        existing_eagerloads = [list(i.path) for i in self.queryset._with_options]
+        if to_join in existing_eagerloads:
+            to_join = []
+
         builder = getattr(self, '_build_clause_{}'.format(spec.lookup))
         column = self._get_attribute_for_field(field)
         clause = builder(spec, column)