position support singular value #1565

mongoengine/queryset/transform.py

@@ -304,10 +304,6 @@ def update(_doc_cls=None, **update):
             value = {match: value}
 
         key = '.'.join(parts)
-        position = None
-        if parts[-1].isdigit() and isinstance(value, (list, tuple, set)):
-            key = parts[0]
-            position = int(parts[-1])
 
         if not op:
             raise InvalidQueryError('Updates must supply an operation '
@@ -339,11 +335,18 @@ def update(_doc_cls=None, **update):
                 value = {key: value}
         elif op == 'addToSet' and isinstance(value, list):
             value = {key: {'$each': value}}
-        elif op == 'push' and isinstance(value, list):
-            if position is not None:
+        elif op == 'push':
+            if parts[-1].isdigit() and op == 'push':
+                key = parts[0]
+                position = int(parts[-1])
+                # position modifier must appear with each.
+                if not isinstance(value, (set, tuple, list)):
+                    value = [value]
                 value = {key: {'$each': value, '$position': position}}
-            else:
+            elif isinstance(value, list):
                 value = {key: {'$each': value}}
+            else:
+                value = {key: value}
         else:
             value = {key: value}
         key = '$' + op