fix duplication entries in add_builtin_snippets

Author: Menrath

classes/snippets.php

@@ -247,10 +247,12 @@ private static function get_builtin_snippet_paths() {
      */
     public static function add_builtin_snippets() {
         global $DB;
+
+        // Get builtin snippets that are present on disk.
         $paths = self::get_builtin_snippet_paths();
 
         // Get builtin snippets which are known in the database.
-        $present = $DB->get_records(
+        $snippets = $DB->get_records(
             'theme_boost_union_snippets',
             ['source' => 'theme_boost_union'],
             'sortorder DESC',
@@ -260,10 +262,15 @@ public static function add_builtin_snippets() {
         );
 
         // Get the highest sortorder present.
-        $sortorder = empty($present) ? 0 : intval(reset($present)->sortorder) + 1;
+        $sortorder = empty($snippets) ? 0 : intval(reset($snippets)->sortorder) + 1;
+
+        // Prepare an array with all the present builtin snippet paths.
+        $presentpaths = array_map(function($snippet) {
+            return $snippet->path;
+        }, $snippets);
 
         foreach ($paths as $path) {
-            if (!array_key_exists($path, $present)) {
+            if (!array_key_exists($path, $presentpaths)) {
                 $DB->insert_record(
                     'theme_boost_union_snippets',
                     [