WHen a guest hits reply, they now get told they have to enrol and

get sent there.   In manual enrolment they are returned to the post
(eventually all the plugins should do that).

enrol/manual/enrol.php

@@ -75,7 +75,7 @@ function print_entry($course) {
                 print_error('couldnotassignrole');
             }
 
-            if ($SESSION->wantsurl) {
+            if (!empty($SESSION->wantsurl)) {
                 $destination = $SESSION->wantsurl;
                 unset($SESSION->wantsurl);
             } else {
@@ -86,7 +86,13 @@ function print_entry($course) {
 
         } else if (!empty($_GET['cancel'])) {
             unset($SESSION->wantsurl);
-            redirect($CFG->wwwroot);
+            if (!empty($SESSION->enrolcancel)) {
+                $destination = $SESSION->enrolcancel;
+                unset($SESSION->enrolcancel);
+            } else {
+                $destination = $CFG->wwwroot;
+            }
+            redirect($destination);
         }
     }
 

lang/en_utf8/moodle.php

@@ -1468,9 +1468,10 @@ $string['yahooid'] = 'Yahoo ID';
 $string['yes'] = 'Yes';
 $string['youareabouttocreatezip'] = 'You are about to create a zip file containing';
 $string['youaregoingtorestorefrom'] = 'You are about to start the restore process for';
+$string['youneedtoenrol'] = 'To perform that action you need to enrol in this course.';
 $string['yourlastlogin'] = 'Your last login was';
 $string['yourself'] = 'yourself';
 $string['yourteacher'] = 'your $a';
 $string['zippingbackup'] = 'Zipping backup';
 
-?>
+?>

mod/forum/post.php

@@ -376,10 +376,17 @@
         if (! $course = get_record("course", "id", $discussion->course)) {
             error("The course number was incorrect ($discussion->course)");
         }
+
         $coursecontext = get_context_instance(CONTEXT_COURSE, $course->id);
         
         if (! forum_user_can_post($forum)) {
-            error("Sorry, but you can not post in this forum.");
+            if (has_capability('moodle/legacy:guest', $coursecontext, NULL, false)) {  // User is a guest here!
+                $SESSION->wantsurl = $FULLME;
+                $SESSION->enrolcancel = $_SERVER['HTTP_REFERER'];
+                redirect($CFG->wwwroot.'/course/enrol.php?id='.$course->id, get_string('youneedtoenrol'));
+            } else {
+                print_error('nopostforum', 'forum');
+            }
         }
         
         if ($cm = get_coursemodule_from_instance("forum", $forum->id, $course->id)) {