Fix Trunc functions RecursionError crash on non-MongoDB databases

django_mongodb_backend/functions.py

@@ -200,6 +200,9 @@ def trunc(self, compiler, connection):
     return {"$dateTrunc": lhs_mql}
 
 
+_trunc_convert_value = TruncBase.convert_value
+
+
 def trunc_convert_value(self, value, expression, connection):
     if connection.vendor == "mongodb":
         # A custom TruncBase.convert_value() for MongoDB.
@@ -224,7 +227,7 @@ def trunc_convert_value(self, value, expression, connection):
                 # Truncate for Trunc(..., output_field=TimeField)
                 value = value.time()
         return value
-    return self.convert_value(value, expression, connection)
+    return _trunc_convert_value(self, value, expression, connection)
 
 
 def trunc_date(self, compiler, connection):

docs/source/releases/5.1.x.rst

@@ -9,6 +9,8 @@ Django MongoDB Backend 5.1.x
 
 - Fixed crash when loading models with a null value for ``ArrayField``\s where
   the ``base_field`` uses a database converter.
+- Fixed ``RecursionError`` when using ``Trunc`` database functions on non-MongoDB
+  databases.
 
 5.1.0 beta 3
 ============

docs/source/releases/5.2.x.rst

@@ -17,6 +17,12 @@ New features
 - Added :class:`~.fields.PolymorphicEmbeddedModelField` for storing a model
   instance that may be of more than one model class.
 
+Bug fixes
+---------
+
+- Fixed ``RecursionError`` when using ``Trunc`` database functions on non-MongoDB
+  databases.
+
 5.2.0 beta 1
 ============