MDL-57390 mod_forum: Return more permissions in can_add_discussion

When adding new discussions we should know if:
- Pinned discussions can be created
- Attachments are supported

mod/forum/classes/message/inbound/reply_handler.php

@@ -173,8 +173,7 @@ class reply_handler extends \core\message\inbound\handler {
         // Add attachments to the post.
         if (!empty($messagedata->attachments['attachment']) && count($messagedata->attachments['attachment'])) {
             $attachmentcount = count($messagedata->attachments['attachment']);
-            if (empty($forum->maxattachments) || $forum->maxbytes == 1 ||
+            if (!forum_can_create_attachment($forum, $modcontext)) {
-                    !has_capability('mod/forum:createattachment', $modcontext)) {
                 // Attachments are not allowed.
                 mtrace("--> User does not have permission to attach files in this forum. Rejecting e-mail.");
 

mod/forum/classes/post_form.php

@@ -133,7 +133,7 @@ class mod_forum_post_form extends moodleform {
             $mform->addHelpButton('discussionsubscribe', 'discussionsubscription', 'forum');
         }
 
-        if (!empty($forum->maxattachments) && $forum->maxbytes != 1 && has_capability('mod/forum:createattachment', $modcontext))  {  //  1 = No attachments at all
+        if (forum_can_create_attachment($forum, $modcontext)) {
             $mform->addElement('filemanager', 'attachments', get_string('attachment', 'forum'), null, self::attachment_options($forum));
             $mform->addHelpButton('attachments', 'attachment', 'forum');
         }

mod/forum/externallib.php

@@ -1129,6 +1129,8 @@ class mod_forum_external extends external_api {
 
         $result = array();
         $result['status'] = $status;
+        $result['canpindiscussions'] = has_capability('mod/forum:pindiscussions', $context);
+        $result['cancreateattachment'] = forum_can_create_attachment($forum, $context);
         $result['warnings'] = $warnings;
         return $result;
     }
@@ -1143,6 +1145,10 @@ class mod_forum_external extends external_api {
         return new external_single_structure(
             array(
                 'status' => new external_value(PARAM_BOOL, 'True if the user can add discussions, false otherwise.'),
+                'canpindiscussions' => new external_value(PARAM_BOOL, 'True if the user can pin discussions, false otherwise.',
+                    VALUE_OPTIONAL),
+                'cancreateattachment' => new external_value(PARAM_BOOL, 'True if the user can add attachments, false otherwise.',
+                    VALUE_OPTIONAL),
                 'warnings' => new external_warnings()
             )
         );

mod/forum/lib.php

@@ -8078,3 +8078,19 @@ function forum_check_updates_since(cm_info $cm, $from, $filter = array()) {
 
     return $updates;
 }
+
+/**
+ * Check if the user can create attachments in a forum.
+ * @param  stdClass $forum   forum object
+ * @param  stdClass $context context object
+ * @return bool true if the user can create attachments, false otherwise
+ * @since  Moodle 3.3
+ */
+function forum_can_create_attachment($forum, $context) {
+    // If maxbytes == 1 it means no attachments at all.
+    if (empty($forum->maxattachments) || $forum->maxbytes == 1 ||
+            !has_capability('mod/forum:createattachment', $context)) {
+        return false;
+    }
+    return true;
+}

mod/forum/tests/externallib_test.php

@@ -1001,7 +1001,7 @@ class mod_forum_external_testcase extends externallib_advanced_testcase {
      * Test can_add_discussion. A basic test since all the API functions are already covered by unit tests.
      */
     public function test_can_add_discussion() {
-
+        global $DB;
         $this->resetAfterTest(true);
 
         // Create courses to add the modules.
@@ -1022,11 +1022,24 @@ class mod_forum_external_testcase extends externallib_advanced_testcase {
         $result = mod_forum_external::can_add_discussion($forum->id);
         $result = external_api::clean_returnvalue(mod_forum_external::can_add_discussion_returns(), $result);
         $this->assertFalse($result['status']);
+        $this->assertFalse($result['canpindiscussions']);
+        $this->assertTrue($result['cancreateattachment']);
+
+        // Disable attachments.
+        $DB->set_field('forum', 'maxattachments', 0, array('id' => $forum->id));
+        $result = mod_forum_external::can_add_discussion($forum->id);
+        $result = external_api::clean_returnvalue(mod_forum_external::can_add_discussion_returns(), $result);
+        $this->assertFalse($result['status']);
+        $this->assertFalse($result['canpindiscussions']);
+        $this->assertFalse($result['cancreateattachment']);
+        $DB->set_field('forum', 'maxattachments', 1, array('id' => $forum->id));    // Enable attachments again.
 
         self::setAdminUser();
         $result = mod_forum_external::can_add_discussion($forum->id);
         $result = external_api::clean_returnvalue(mod_forum_external::can_add_discussion_returns(), $result);
         $this->assertTrue($result['status']);
+        $this->assertTrue($result['canpindiscussions']);
+        $this->assertTrue($result['cancreateattachment']);
 
     }
 

mod/forum/upgrade.txt

@@ -4,9 +4,12 @@ information provided here is intended especially for developers.
 === 3.3 ===
   * External function get_forums_by_courses now returns and additional field "istracked" that indicates if the user
    is tracking the related forum.
-* The legacy forum.js file has been removed, this includes the js functions:
+  * The legacy forum.js file has been removed, this includes the js functions:
     forum_produce_subscribe_link, forum_produce_tracking_link, lockoptions_timetoitems,
     lockoptions_timefromitems, lockoptions, lockoption, unlockoption
+  * External function can_add_discussion now returns two additional fields:
+   "canpindiscussions" that indicates if the user can add pinned discussions.
+   "cancreateattachment" that indicates if the user can add attachments to the discussion.
 
 === 3.2 ===
  * The setting $CFG->forum_replytouser has been removed in favour of a centralized noreplyaddress setting.