Handle refs from foreign collections.

Author: WaVEV

django_mongodb/compiler.py

@@ -428,32 +428,22 @@ def _get_aggregate_expressions(self, expr):
                 stack.extend(expr.get_source_expressions())
 
     def get_project_fields(self, columns=None, ordering=None):
-        fields = {}
+        fields = defaultdict(dict)
         for name, expr in columns or []:
+            collection = expr.alias if isinstance(expr, Col) else None
             try:
-                column = expr.target.column
-            except AttributeError:
-                # Generate the MQL for an annotation.
-                try:
-                    fields[name] = expr.as_mql(self, self.connection)
-                except EmptyResultSet:
-                    fields[name] = Value(False).as_mql(self, self.connection)
-                except FullResultSet:
-                    fields[name] = Value(True).as_mql(self, self.connection)
-            else:
-                # If name != column, then this is an annotatation referencing
-                # another column.
-                fields[name] = 1 if name == column else f"${column}"
-        if fields:
-            # Add related fields.
-            for alias in self.query.alias_map:
-                if self.query.alias_refcount[alias] and self.collection_name != alias:
-                    fields[alias] = 1
+                fields[collection][name] = expr.as_mql(self, self.connection)
+            except EmptyResultSet:
+                fields[collection][name] = Value(False).as_mql(self, self.connection)
+            except FullResultSet:
+                fields[collection][name] = Value(True).as_mql(self, self.connection)
+        # Unwrap annotations.
+        fields.update(fields.pop(None, {}))
+        # Unwrap main collection's fields.
+        fields.update(fields.pop(self.collection_name, {}))
+        if fields and ordering:
             # Add order_by() fields.
-            for alias, expression in ordering or []:
-                nested_entity = alias.split(".", 1)[0] if "." in alias else None
-                if alias not in fields and nested_entity not in fields:
-                    fields[alias] = expression.as_mql(self, self.connection)
+            fields.update({alias: expr.as_mql(self, self.connection) for alias, expr in ordering})
         return fields
 
     def _get_ordering(self):

django_mongodb/expressions.py

@@ -77,7 +77,12 @@ def query(self, compiler, connection):  # noqa: ARG001
 
 
 def ref(self, compiler, connection):  # noqa: ARG001
-    return f"${self.refs}"
+    prefix = (
+        f"{self.source.alias}."
+        if isinstance(self.source, Col) and self.source.alias != compiler.collection_name
+        else ""
+    )
+    return f"${prefix}{self.refs}"
 
 
 def star(self, compiler, connection):  # noqa: ARG001

django_mongodb/features.py

@@ -50,12 +50,6 @@ class DatabaseFeatures(BaseDatabaseFeatures):
         # Length of null considered zero rather than null.
         "db_functions.text.test_length.LengthTests.test_basic",
         # Wrong results in queries with multiple tables.
-        "annotations.tests.NonAggregateAnnotationTestCase.test_annotation_reverse_m2m",
-        "annotations.tests.NonAggregateAnnotationTestCase.test_annotation_with_m2m",
-        "annotations.tests.NonAggregateAnnotationTestCase.test_chaining_annotation_filter_with_m2m",
-        "annotations.tests.NonAggregateAnnotationTestCase.test_mti_annotations",
-        "expressions.test_queryset_values.ValuesExpressionsTests.test_values_list_expression",
-        "expressions.test_queryset_values.ValuesExpressionsTests.test_values_list_expression_flat",
         "expressions.tests.IterableLookupInnerExpressionsTests.test_expressions_in_lookups_join_choice",
         "queries.tests.Queries1Tests.test_order_by_tables",
         "queries.tests.TestTicket24605.test_ticket_24605",