Minor - Fix php errors, warnings

main/gradebook/lib/GradebookUtils.php

@@ -1188,6 +1188,7 @@ class GradebookUtils
      * returns users within a course given by param.
      *
      * @param string $courseCode
+     * @deprecated use CourseManager
      *
      * @return array
      */
@@ -1218,7 +1219,7 @@ class GradebookUtils
             $sql = 'SELECT user.user_id, user.username, lastname, firstname, official_code
                     FROM '.$tbl_course_user.' as course_rel_user 
                     INNER JOIN '.$tbl_user.' as user
-                    ON (course_rel_user.user_id=user.user_id)
+                    ON (course_rel_user.user_id = user.id)
                     WHERE
                         course_rel_user.status = '.STUDENT.' AND
                         course_rel_user.c_id = "'.$courseId.'" '.

main/gradebook/lib/fe/linkaddeditform.class.php

@@ -11,8 +11,8 @@
  */
 class LinkAddEditForm extends FormValidator
 {
-    const TYPE_ADD = 1;
-    const TYPE_EDIT = 2;
+    public const TYPE_ADD = 1;
+    public const TYPE_EDIT = 2;
 
     /**
      * Constructor

main/gradebook/lib/fe/userform.class.php

@@ -11,8 +11,8 @@
  */
 class UserForm extends FormValidator
 {
-    const TYPE_USER_INFO = 1;
-    const TYPE_SIMPLE_SEARCH = 3;
+    public const TYPE_USER_INFO = 1;
+    public const TYPE_SIMPLE_SEARCH = 3;
 
     /**
      * Builds a form containing form items based on a given parameter.

main/inc/lib/pdf.lib.php

@@ -123,6 +123,8 @@ class PDF
         // Assignments
         $tpl->assign('pdf_content', $content);
 
+        $teacher_list = [];
+
         // Showing only the current teacher/admin instead the all teacher list name see BT#4080
         if (isset($this->params['show_real_course_teachers']) &&
             $this->params['show_real_course_teachers']