From 7666119f3118e67ca2d23123c80e1d4d908145a4 Mon Sep 17 00:00:00 2001
From: Miroslav Shubernetskiy <miroslav@miki725.com>
Date: Wed, 8 Aug 2018 14:01:08 -0400
Subject: [PATCH] not joining already eager loaded models

---
 HISTORY.rst                       |  6 ++++++
 tests/backends/test_sqlalchemy.py | 15 +++++++++++++++
 url_filter/__init__.py            |  2 +-
 url_filter/backends/sqlalchemy.py |  4 ++++
 4 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/HISTORY.rst b/HISTORY.rst
index 828b772..189a249 100644
--- a/HISTORY.rst
+++ b/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)
 ~~~~~~~~~~~~~~~~~~
 
diff --git a/tests/backends/test_sqlalchemy.py b/tests/backends/test_sqlalchemy.py
index 335590d..c2840cc 100644
--- a/tests/backends/test_sqlalchemy.py
+++ b/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),
diff --git a/url_filter/__init__.py b/url_filter/__init__.py
index 0cad69c..de10cd1 100644
--- a/url_filter/__init__.py
+++ b/url_filter/__init__.py
@@ -4,4 +4,4 @@
 
 __author__ = 'Miroslav Shubernetskiy'
 __email__ = 'miroslav@miki725.com'
-__version__ = '0.3.7'
+__version__ = '0.3.8'
diff --git a/url_filter/backends/sqlalchemy.py b/url_filter/backends/sqlalchemy.py
index 09f328c..27dc96a 100644
--- a/url_filter/backends/sqlalchemy.py
+++ b/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)