fix: Listify initial field value when SearchableField.max_entries == 1 (ietf-tools#4951)

* fix: Listify initial field value when SearchableField.max_entries == 1

* fix: Don't convert initial=None to initial=[None] in has_changed()

Author: jennifer-richards

ietf/utils/fields.py

@@ -320,6 +320,13 @@ def clean(self, pks):
 
         return objs.first() if self.max_entries == 1 else objs
 
+    def has_changed(self, initial, data):
+        # When max_entries == 1, we behave like a ChoiceField so initial will likely be a single
+        # value. Make it a list so MultipleChoiceField's has_changed() can work with it.
+        if initial is not None and self.max_entries == 1 and not isinstance(initial, (list, tuple)):
+            initial = [initial]
+        return super().has_changed(initial, data)
+
 
 class IETFJSONField(jsonfield.fields.forms.JSONField):
     def __init__(self, *args, empty_values=jsonfield.fields.forms.JSONField.empty_values,