edits

Author: timgraham

django_mongodb/compiler.py

@@ -442,6 +442,8 @@ def collection_name(self):
                 if isinstance(v, BaseTable) and self.query.alias_refcount[k]
             )
         except StopIteration:
+            # Use a dummy collection if the query doesn't specify a table
+            # (such as Constraint.validate() with a condition).
             query = self.query_class(self)
             query.aggregation_pipeline = [{"$facet": {"__null": []}}]
             self.subqueries.insert(0, query)

django_mongodb/features.py

@@ -23,6 +23,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
     supports_expression_indexes = False
     supports_foreign_keys = False
     supports_ignore_conflicts = False
+    # Before MongoDB 6.0, $in cannot be used in partialFilterExpression.
     supports_in_index_operator = property(operator.attrgetter("is_mongodb_6_0"))
     supports_json_field_contains = False
     # BSON Date type doesn't support microsecond precision.
@@ -97,7 +98,6 @@ class DatabaseFeatures(BaseDatabaseFeatures):
         "expressions.tests.ExpressionOperatorTests.test_lefthand_bitwise_xor_right_null",
         "expressions.tests.ExpressionOperatorTests.test_lefthand_transformed_field_bitwise_or",
     }
-    # Before MongoDB 6.0, $in cannot be used in partialFilterExpression.
     _django_test_expected_failures_partial_expression_in = {
         "schema.tests.SchemaTests.test_remove_ignored_unique_constraint_not_create_fk_index",
     }
@@ -106,7 +106,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
     def django_test_expected_failures(self):
         expected_failures = super().django_test_expected_failures
         expected_failures.update(self._django_test_expected_failures)
-        if not self.is_mongodb_6_0:
+        if not self.supports_in_index_operator:
             expected_failures.update(self._django_test_expected_failures_partial_expression_in)
         if not self.is_mongodb_6_3:
             expected_failures.update(self._django_test_expected_failures_bitwise)

django_mongodb/indexes.py

@@ -9,7 +9,7 @@
 
 from .query_utils import process_rhs
 
-mongo_operators_idx = {
+MONGO_INDEX_OPERATORS = {
     "exact": "$eq",
     "gt": "$gt",
     "gte": "$gte",
@@ -33,7 +33,7 @@ def builtin_lookup_idx(self, compiler, connection):
     lhs_mql = self.lhs.target.column
     value = process_rhs(self, compiler, connection)
     try:
-        operator = mongo_operators_idx[self.lookup_name]
+        operator = MONGO_INDEX_OPERATORS[self.lookup_name]
     except KeyError:
         raise NotSupportedError(
             f"MongoDB does not support the '{self.lookup_name}' lookup in indexes."

django_mongodb/lookups.py

@@ -51,9 +51,7 @@ def is_null(self, compiler, connection):
     if not isinstance(self.rhs, bool):
         raise ValueError("The QuerySet value for an isnull lookup must be True or False.")
     if isinstance(self.lhs, Value):
-        if self.lhs.value is None or (
-            self.lhs.value == "" and connection.features.interprets_empty_strings_as_nulls
-        ):
+        if self.lhs.value is None:
             result_exception = FullResultSet if self.rhs else EmptyResultSet
         else:
             result_exception = EmptyResultSet if self.rhs else FullResultSet