MDL-12922 restore roll dates - prevent wrong rolls to 0 happening to teachers. Backported from HEAD

backup/restore_check.html

@@ -22,8 +22,8 @@
         $course_header->course_fullname =   stripslashes_safe($form1->fullname);   //"update_FullName";  
     /// Roll dates only if the backup course has a start date
     /// (some formats like main page, social..., haven't it and rolling dates
-    /// from 0 produces crazy dates. MDL-10125
-        if ($course_header->course_startdate) {
+    /// from 0 produces crazy dates. MDL-10125 and we have passed some custom startyear/month/day. MDL-12922
+        if ($course_header->course_startdate && !empty($form1->startyear)) {
             $form1->startdate = make_timestamp($form1->startyear, $form1->startmonth, $form1->startday);
             $currentcoursestartdate = $course_header->course_startdate;
             $coursestartdatedateoffset = $form1->startdate - $currentcoursestartdate;

backup/restore_form.html

@@ -254,6 +254,11 @@ function selectItemInCheckboxByName(formId, checkName, checked ) {
         }
         helpbutton("coursestartdate", get_string("startdate"));
         echo "</td></tr>";
+    } else {
+    /// If user cannot create course, prevent any change in startyear/month/day (so restore wont calculate any roll. MDL-12922
+        echo '<input type="hidden" name="startyear" value="0" />';
+        echo '<input type="hidden" name="startmonth" value="0" />';
+        echo '<input type="hidden" name="startday" value="0" />';
     }
     //Line
     echo "<tr><td colspan=\"4\"><hr /></td></tr>";
@@ -635,4 +640,4 @@ function restore_is_samerole($rolea, $roleb) {
     }
     return true;
 }
-?>
+?>