with dovecot $HasAttachment/$HasNoAttachment rc doesn't see header info: subject, from, to

[bes-internal]

Dovecot 2.4.2 enable by default $HasAttachment/$HasNoAttachment by mail_attachment_detection_options

Roundcube 1.6.11 (php 8.2) for new messages return no header information (subject, from, to...) in message view panel.
This only happens the first time I open a message. The second and subsequent times, everything works fine.

With imap_debug i can create this diff. Where left is dovecot 2.3.21.1 and right is 2.4.2 ( see FLAGS ($HasNoAttachment) ):

1c1
< S: A0001 OK [CAPABILITY IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE IDLE SORT SORT=DISPLAY THREAD=REFERENCES THREAD=REFS THREAD=ORDEREDSUBJECT MULTIAPPEND URL-PARTIAL CATENATE UNSELECT CHILDREN NAMESPACE UIDPLUS LIST-EXTENDED I18NLEVEL=1 CONDSTORE QRESYNC ESEARCH ESORT SEARCHRES WITHIN CONTEXT=SEARCH LIST-STATUS BINARY MOVE SNIPPET=FUZZY PREVIEW=FUZZY PREVIEW STATUS=SIZE SAVEDATE LITERAL+ NOTIFY SPECIAL-USE] Logged in
---
> S: A0001 OK [CAPABILITY IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE IDLE SORT SORT=DISPLAY THREAD=REFERENCES THREAD=REFS THREAD=ORDEREDSUBJECT MULTIAPPEND URL-PARTIAL CATENATE UNSELECT CHILDREN NAMESPACE UIDPLUS LIST-EXTENDED I18NLEVEL=1 CONDSTORE QRESYNC ESEARCH ESORT SEARCHRES WITHIN CONTEXT=SEARCH LIST-STATUS BINARY MOVE REPLACE SNIPPET=FUZZY PREVIEW=FUZZY PREVIEW SPECIAL-USE STATUS=SIZE SAVEDATE COMPRESS=DEFLATE INPROGRESS NOTIFY LITERAL+] Logged in
16c16
< S: * 661 FETCH (UID 214760 RFC822.SIZE 1830 FLAGS () INTERNALDATE "05-Dec-2025 14:21:58 +0300" BODYSTRUCTURE (("text" "html" ("charset" "UTF-8") NIL NIL "8bit" 894 12 NIL NIL NIL NIL) "mixed" ("boundary" "zzzpartzzz") NIL NIL NIL) BODY[HEADER.FIELDS (DATE FROM TO SUBJECT CONTENT-TYPE CC REPLY-TO LIST-POST DISPOSITION-NOTIFICATION-TO X-PRIORITY CONTENT-TRANSFER-ENCODING BCC IN-REPLY-TO MAIL-FOLLOWUP-TO MAIL-REPLY-TO MESSAGE-ID REFERENCES RESENT-BCC RETURN-PATH SENDER X-DRAFT-INFO)] {444}
---
> S: * 661 FETCH (UID 214760 RFC822.SIZE 1830 FLAGS ($HasNoAttachment) INTERNALDATE "05-Dec-2025 14:21:58 +0300" BODYSTRUCTURE (("text" "html" ("charset" "UTF-8") NIL NIL "8bit" 894 12 NIL NIL NIL NIL) "mixed" ("boundary" "zzzpartzzz") NIL NIL NIL) BODY[HEADER.FIELDS (DATE FROM TO SUBJECT CONTENT-TYPE CC REPLY-TO LIST-POST DISPOSITION-NOTIFICATION-TO X-PRIORITY CONTENT-TRANSFER-ENCODING BCC IN-REPLY-TO MAIL-FOLLOWUP-TO MAIL-REPLY-TO MESSAGE-ID REFERENCES RESENT-BCC RETURN-PATH SENDER X-DRAFT-INFO)] {444}

Full log for 2.4.2

S: A0001 OK [CAPABILITY IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE IDLE SORT SORT=DISPLAY THREAD=REFERENCES THREAD=REFS THREAD=ORDEREDSUBJECT MULTIAPPEND URL-PARTIAL CATENATE UNSELECT CHILDREN NAMESPACE UIDPLUS LIST-EXTENDED I18NLEVEL=1 CONDSTORE QRESYNC ESEARCH ESORT SEARCHRES WITHIN CONTEXT=SEARCH LIST-STATUS BINARY MOVE REPLACE SNIPPET=FUZZY PREVIEW=FUZZY PREVIEW SPECIAL-USE STATUS=SIZE SAVEDATE COMPRESS=DEFLATE INPROGRESS NOTIFY LITERAL+] Logged in
C: A0002 ID ("name" "Roundcube" "version" "1.6-git" "php" "8.2.29" "os" "Linux" "command" "/?_task=mail&_caps=pdf%3D1%2Cflash%3D0%2Ctiff%3D0%2Cwebp%3D1%2Cpgpmime%3D0&_uid=214760&_mbox=INBOX&_framed=1&_action=preview")
S: * ID ("name" "Dovecot")
S: A0002 OK ID completed (0.001 + 0.000 secs).
C: A0003 SELECT INBOX
S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft NonJunk $Forwarded $MDNSent encrypted $HasAttachment $HasNoAttachment)
S: * OK [PERMANENTFLAGS (\Answered \Flagged \Deleted \Seen \Draft NonJunk $Forwarded $MDNSent encrypted $HasAttachment $HasNoAttachment \*)] Flags permitted.
S: * 662 EXISTS
S: * 0 RECENT
S: * OK [UNSEEN 661] First unseen.
S: * OK [UIDVALIDITY 1528717329] UIDs valid
S: * OK [UIDNEXT 214763] Predicted next UID
S: * OK [HIGHESTMODSEQ 321378] Highest
S: A0003 OK [READ-WRITE] Select completed (0.001 + 0.000 secs).
C: A0004 UID FETCH 214760 (UID RFC822.SIZE FLAGS INTERNALDATE BODYSTRUCTURE BODY.PEEK[HEADER.FIELDS (DATE FROM TO SUBJECT CONTENT-TYPE CC REPLY-TO LIST-POST DISPOSITION-NOTIFICATION-TO X-PRIORITY CONTENT-TRANSFER-ENCODING BCC IN-REPLY-TO MAIL-FOLLOWUP-TO MAIL-REPLY-TO MESSAGE-ID REFERENCES RESENT-BCC RETURN-PATH SENDER X-DRAFT-INFO)])
S: * 661 FETCH (UID 214760 RFC822.SIZE 1830 FLAGS ($HasNoAttachment) INTERNALDATE "05-Dec-2025 14:21:58 +0300" BODYSTRUCTURE (("text" "html" ("charset" "UTF-8") NIL NIL "8bit" 894 12 NIL NIL NIL NIL) "mixed" ("boundary" "zzzpartzzz") NIL NIL NIL) BODY[HEADER.FIELDS (DATE FROM TO SUBJECT CONTENT-TYPE CC REPLY-TO LIST-POST DISPOSITION-NOTIFICATION-TO X-PRIORITY CONTENT-TRANSFER-ENCODING BCC IN-REPLY-TO MAIL-FOLLOWUP-TO MAIL-REPLY-TO MESSAGE-ID REFERENCES RESENT-BCC RETURN-PATH SENDER X-DRAFT-INFO)] {444}
S: Return-path: .... [message headers part] ....

P.S.
As a temporary solution, you can to return the settings back to: mail_attachment_detection_options="" in dovecot.conf

[alecpl]

I attempted to emulate the issue with this patch

-- a/program/lib/Roundcube/rcube_imap_generic.php
+++ b/program/lib/Roundcube/rcube_imap_generic.php
@@ -2498,6 +2498,7 @@ class rcube_imap_generic
 
                 $headers = null;
                 $line = substr($line, strlen($m[0]) + 2);
+                $line = preg_replace('/FLAGS \([^)]*\)/', 'FLAGS ($HasNoAttachment)', $line);
                 // Tokenize response and assign to object properties
                 while (($tokens = $this->tokenizeResponse($line, 2)) && count($tokens) == 2) {
                     [$name, $value] = $tokens;

but I couldn't reproduce it in git-master.

[bes-internal]

Moved to the latest release 1.6.12.
Now the headings are displayed correctly, but the message itself is broken when first opened.

When open new message with attachement (rc 1.6.12, dovecot 2.4.2 + default mail_attachment_detection_options=add-flags content-type=!application/signature):

When open this message in seccond time: