Merge pull request #1438 from maths/iss1436

iss1436 - Question library fixes

Author: sangwinc

stack/cas/castext2/blocks/textdownload.block.php

@@ -95,6 +95,9 @@ public function postprocess(array $params, castext2_processor $processor,
         castext2_placeholder_holder $holder): string {
         if (get_config('qtype_stack', 'stackapi')) {
             return "javascript:download('{$params[1]}', {$params[2]});";
+        } else if (!isset($processor->qa) || !function_exists($processor->qa->get_database_id)) {
+            // ISS1436 - Basic fix for STACK library where there is no question attempt.
+            return "#";
         } else {
             // Note different systems serve out through different logic.
             if (count($params) > 3 && $params[3] === 'stateful') {

stack/input/inputbase.class.php

@@ -1422,7 +1422,9 @@ public function requires_validation() {
      * @param string student's current answer to insert into the xhtml.
      * @param string $fieldname the field name to use in the HTML for this input.
      * @param bool $readonly whether the control should be displayed read-only.
-     * @param array $tavalue the value of the teacher's answer for this input.
+     * ISS1436 - As far as I can tell, only equiv input is using $tavalue
+     * and that's expecting a string not an array.
+     * @param string $tavalue the value of the teacher's answer for this input.
      * @return string HTML for this input.
      */
     abstract public function render(stack_input_state $state, $fieldname, $readonly, $tavalue);

stack/questionlibrary.class.php

@@ -90,7 +90,9 @@ public static function render_question(object $question): string {
             $tavalue = $question->get_ta_for_input($name);
             $fieldname = 'stack_temp_' . $name;
             $state = $question->get_input_state($name, []);
-            $render = $input->render($state, $fieldname, false, [$tavalue]);
+            // ISS1436 - As far as I can tell, only equiv input is using $tavalue
+            // and that's expecting a string not an array.
+            $render = $input->render($state, $fieldname, false, $tavalue);
             StackPlotReplacer::replace_plots($plots, $render, "answer-".$name, $storeprefix);
             $questiontext = str_replace("[[input:{$name}]]",
                 $render,