make removeItems handle empty sets better

Author: jennybuckley

typed/remove.go

@@ -86,6 +86,10 @@ func (w *removingWalker) doList(t schema.List) (errs ValidationErrors) {
 		newItems = append(newItems, l.Items[i])
 	}
 	l.Items = newItems
+	if len(l.Items) == 0 {
+		w.value.ListValue = nil
+		w.value.Null = true
+	}
 	return nil
 }
 
@@ -111,6 +115,10 @@ func (w *removingWalker) doMap(t schema.Map) ValidationErrors {
 		newMap.Set(item.Name, m.Items[i].Value)
 	}
 	w.value.MapValue = newMap
+	if len(w.value.MapValue.Items) == 0 {
+		w.value.MapValue = nil
+		w.value.Null = true
+	}
 	return nil
 }