Prevent blank penalties being changed to 0.

doc/en/Developer/Development_track.md

@@ -59,7 +59,7 @@ At this point STACK will be "ready" for use with students, although not all feat
  1. **DONE** Only deploy new versions.
 5. Editing form
  1. Button to remove a node from a PRT.
-6. Fix bug: penalties and other fields being changed from NULL to 0 when being stored in the database.
+6. **DONE** Fix bug: penalties and other fields being changed from NULL to 0 when being stored in the database.
 7. Add back Matrix input type. (currently only need to deal with naming of fields, and add tests)
 8. Finish off the system for running Maxima on another server (https://github.com/maths/moodle-qtype_stack/pull/8)
 

edit_stack_form.php

@@ -223,6 +223,7 @@ class qtype_stack_edit_form extends question_edit_form {
         $mform->insertElementBefore($pen, 'generalfeedback');
         $mform->addHelpButton('penalty', 'penalty', 'qtype_stack');
         $mform->setDefault('penalty', 0.1000000);
+        $mform->addRule('penalty', null, 'required', null, 'client');
 
         $sf = $mform->createElement('editor', 'specificfeedback',
                 get_string('specificfeedback', 'question'), array('rows' => 10), $this->editoroptions);

questiontype.php

@@ -178,6 +178,13 @@ class qtype_stack extends question_type {
                                 $context, 'qtype_stack', 'prtnodefalsefeedback', $node->id);
                 $node->falsefeedbackformat  = $fromform->{$prtname . 'falsefeedback'}[$nodename]['format'];
 
+                if ('' === $node->truepenalty) {
+                    $node->truepenalty = null;
+                }
+                if ('' === $node->falsepenalty) {
+                    $node->falsepenalty = null;
+                }
+
                 $DB->update_record('qtype_stack_prt_nodes', $node);
             }