Polish the wrapping logic

Author: WaVEV

django_mongodb_backend/compiler.py

@@ -240,7 +240,7 @@ def _build_aggregation_pipeline(self, ids, group):
         if not ids:
             pipeline.append({"$group": {"_id": None, **group}})
             # If ids is empty, a global group-by is applied
-            self.wrap_for_global_aggregation = True
+            self.wrap_for_global_aggregation = not bool(self.having)
         else:
             group["_id"] = ids
             pipeline.append({"$group": group})
@@ -326,7 +326,7 @@ def pre_sql_setup(self, with_col_aliases=False):
                     pipeline.extend(query.get_pipeline())
                 # Remove the added subqueries.
                 self.subqueries = []
-                self.having_match_mql = having
+                pipeline.append({"$match": having})
             self.aggregation_pipeline = pipeline
         self.annotations = {
             target: expr.replace_expressions(all_replacements)

django_mongodb_backend/query.py

@@ -50,7 +50,6 @@ def __init__(self, compiler):
         self.lookup_pipeline = None
         self.project_fields = None
         self.aggregation_pipeline = compiler.aggregation_pipeline
-        self.having = compiler.having_match_mql
         self.search_pipeline = compiler.search_pipeline
         self.extra_fields = None
         self.combinator_pipeline = None
@@ -96,8 +95,6 @@ def get_pipeline(self):
         if self.wrap_for_global_aggregation:
             # Add an empty extra document to handle default values on empty results
             pipeline.append({"$unionWith": {"pipeline": [{"$documents": [{}]}]}})
-        if self.having:
-            pipeline.append({"$match": self.having})
         if self.project_fields:
             pipeline.append({"$project": self.project_fields})
         if self.combinator_pipeline: