edits

Author: timgraham

django_mongodb/compiler.py

@@ -332,17 +332,15 @@ def build_query(self, columns=None):
         """Check if the query is supported and prepare a MongoQuery."""
         self.check_query()
         query = self.query_class(self)
-        query.aggregation_pipeline = self.aggregation_pipeline
         query.lookup_pipeline = self.get_lookup_pipeline()
         query.order_by(self._get_ordering())
         query.project_fields = self.get_project_fields(columns, ordering=query.ordering)
         try:
-            where = self.get_where()
-            query.mongo_query = (
-                {"$expr": where.as_mql(self, self.connection)} if where is not None else {}
-            )
+            expr = self.where.as_mql(self, self.connection) if self.where else {}
         except FullResultSet:
             query.mongo_query = {}
+        else:
+            query.mongo_query = {"$expr": expr}
         return query
 
     def get_columns(self):
@@ -480,9 +478,6 @@ def get_project_fields(self, columns=None, ordering=None):
                     fields[column] = 1
         return fields
 
-    def get_where(self):
-        return self.where
-
 
 class SQLInsertCompiler(SQLCompiler):
     def execute_sql(self, returning_fields=None):
@@ -528,7 +523,8 @@ def check_query(self):
                 "Cannot use QuerySet.delete() when querying across multiple collections on MongoDB."
             )
 
-    def get_where(self):
+    @property
+    def where(self):
         return self.query.where
 
 
@@ -592,15 +588,15 @@ def check_query(self):
                 "Cannot use QuerySet.update() when querying across multiple collections on MongoDB."
             )
 
-    def get_where(self):
+    @property
+    def where(self):
         return self.query.where
 
 
 class SQLAggregateCompiler(SQLCompiler):
     def build_query(self, columns=None):
         query = self.query_class(self)
         query.project_fields = self.get_project_fields(tuple(self.annotations.items()))
-        query.aggregation_pipeline = self.aggregation_pipeline
         compiler = self.query.inner_query.get_compiler(
             self.using,
             elide_empty=self.elide_empty,

django_mongodb/features.py

@@ -108,8 +108,6 @@ class DatabaseFeatures(BaseDatabaseFeatures):
         "aggregation.tests.AggregateTestCase.test_aggregation_default_passed_another_aggregate",
         "aggregation.tests.AggregateTestCase.test_annotation_expressions",
         "aggregation.tests.AggregateTestCase.test_reverse_fkey_annotate",
-        # Manage empty result when the flag elide_empty is False.
-        "aggregation.tests.AggregateTestCase.test_empty_result_optimization",
         # Incorrect order: pipeline does not order by the correct fields.
         "aggregation.tests.AggregateTestCase.test_annotate_ordering",
         "aggregation.tests.AggregateTestCase.test_even_more_aggregate",
@@ -504,6 +502,7 @@ def django_test_expected_failures(self):
         "Custom aggregations/functions with SQL don't work on MongoDB.": {
             "aggregation.tests.AggregateTestCase.test_add_implementation",
             "aggregation.tests.AggregateTestCase.test_multi_arg_aggregate",
+            "aggregation.tests.AggregateTestCase.test_empty_result_optimization",
             "annotations.tests.NonAggregateAnnotationTestCase.test_custom_functions",
             "annotations.tests.NonAggregateAnnotationTestCase.test_custom_functions_can_ref_other_functions",
         },

django_mongodb/query.py

@@ -50,7 +50,7 @@ def __init__(self, compiler):
         self.subquery = None
         self.lookup_pipeline = None
         self.project_fields = None
-        self.aggregation_pipeline = None
+        self.aggregation_pipeline = compiler.aggregation_pipeline
 
     def __repr__(self):
         return f"<MongoQuery: {self.mongo_query!r} ORDER {self.ordering!r}>"