render_const() notify if document was undefined and changed after render()

jsonform/gadget_json_generated_form_child.js

@@ -199,12 +199,15 @@
     return input;
   }
 
-  function render_const(schema, json_document) {
+  function render_const(g, schema, json_document) {
     var input = document.createElement("input"),
       ser_doc = JSON.stringify(json_document),
       ser_const = JSON.stringify(schema.const);
     input.setAttribute('readonly', true);
     if (json_document === undefined || deepEqual(json_document, schema.const)) {
+      if (json_document === undefined) {
+        g.props.changed = true;
+      }
       input.setAttribute('data-origin-value', ser_const);
       input.value = ser_const;
     } else {
@@ -880,7 +883,7 @@
     div_input.setAttribute("class", "input");
 
     if (json_field.const !== undefined) {
-      input = render_const(json_field, default_value);
+      input = render_const(gadget, json_field, default_value);
     } else if (json_field.enum !== undefined) {
       input = render_enum(gadget, json_field, default_value);
       // XXX take in account existing type with enum
@@ -888,7 +891,7 @@
     }
 
     if (!input && type === "null") {
-      input = render_const({const: null}, default_value);
+      input = render_const(gadget, {const: null}, default_value);
     }
 
     if (!input && type === "boolean") {