MDL-54055 gradingform_guide: Skip insertion of empty comments

We should not be adding empty entries for the frequently-used comments.

grade/grading/form/guide/db/upgrade.php

@@ -0,0 +1,50 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * This file keeps track of upgrades to the marking guide grading method.
+ *
+ * @package   gradingform_guide
+ * @category  upgrade
+ * @copyright 2016 Jun Pataleta
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * Marking guide grading method upgrade task.
+ *
+ * @param int $oldversion The version we are upgrading form.
+ * @return bool Returns true on success.
+ * @throws coding_exception
+ * @throws downgrade_exception
+ * @throws upgrade_exception
+ */
+function xmldb_gradingform_guide_upgrade($oldversion) {
+    global $DB;
+
+    if ($oldversion < 2016051100) {
+        // Clean up empty string or null marking guide comments.
+        $sql = $DB->sql_isempty('gradingform_guide_comments', 'description', true, true);
+        $sql .= " OR description IS NULL ";
+        $DB->delete_records_select('gradingform_guide_comments', $sql);
+        // Main savepoint reached.
+        upgrade_plugin_savepoint(true, 2016051100, 'gradingform', 'guide');
+    }
+
+    return true;
+}

grade/grading/form/guide/lib.php

@@ -213,6 +213,16 @@ public function update_or_check_guide(stdClass $newdefinition, $usermodified = n
                 $data = array('definitionid' => $this->definition->id, 'descriptionformat' => FORMAT_MOODLE);
                 foreach ($commentfields as $key) {
                     if (array_key_exists($key, $comment)) {
+                        // Check if key is the comment's description.
+                        if ($key === 'description') {
+                            // Get a trimmed value for the comment description.
+                            $description = trim($comment[$key]);
+                            // Check if the comment description is empty.
+                            if (empty($description)) {
+                                // Continue to the next comment object if the description is empty.
+                                continue 2;
+                            }
+                        }
                         $data[$key] = $comment[$key];
                     }
                 }

grade/grading/form/guide/version.php

@@ -25,6 +25,6 @@
 defined('MOODLE_INTERNAL') || die();
 
 $plugin->component  = 'gradingform_guide';
-$plugin->version    = 2015111600;
+$plugin->version    = 2016051100;
 $plugin->requires   = 2015111000;
 $plugin->maturity   = MATURITY_STABLE;