MDL-60591 mod_forum: inline attachments are not displayed in plain text

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

@@ -170,9 +170,20 @@ public function process_message(\stdClass $record, \stdClass $messagedata) {
         // We don't trust text coming from e-mail.
         $addpost->messagetrust = false;
 
+        // Find all attachments. If format is plain text, treat inline attachments as regular ones.
+        $attachments = !empty($messagedata->attachments['attachment']) ? $messagedata->attachments['attachment'] : [];
+        $inlineattachments = [];
+        if (!empty($messagedata->attachments['inline'])) {
+            if ($addpost->messageformat == FORMAT_HTML) {
+                $inlineattachments = $messagedata->attachments['inline'];
+            } else {
+                $attachments = array_merge($attachments, $messagedata->attachments['inline']);
+            }
+        }
+
         // Add attachments to the post.
-        if (!empty($messagedata->attachments['attachment']) && count($messagedata->attachments['attachment'])) {
-            $attachmentcount = count($messagedata->attachments['attachment']);
+        if ($attachments) {
+            $attachmentcount = count($attachments);
             if (!forum_can_create_attachment($forum, $modcontext)) {
                 // Attachments are not allowed.
                 mtrace("--> User does not have permission to attach files in this forum. Rejecting e-mail.");
@@ -196,7 +207,7 @@ public function process_message(\stdClass $record, \stdClass $messagedata) {
 
             $filesize = 0;
             $addpost->attachments  = file_get_unused_draft_itemid();
-            foreach ($messagedata->attachments['attachment'] as $attachment) {
+            foreach ($attachments as $attachment) {
                 mtrace("--> Processing {$attachment->filename} as an attachment.");
                 $this->process_attachment('*', $usercontext, $addpost->attachments, $attachment);
                 $filesize += $attachment->filesize;
@@ -215,8 +226,8 @@ public function process_message(\stdClass $record, \stdClass $messagedata) {
         }
 
         // Process any files in the message itself.
-        if (!empty($messagedata->attachments['inline'])) {
-            foreach ($messagedata->attachments['inline'] as $attachment) {
+        if ($inlineattachments) {
+            foreach ($inlineattachments as $attachment) {
                 mtrace("--> Processing {$attachment->filename} as an inline attachment.");
                 $this->process_attachment('*', $usercontext, $addpost->itemid, $attachment);