[network/kaidan] src: MessageController: Only store stanza ID with expected 'by' attribute

Git commit 41069ebeca7f1627c5b1818a0105c4396dea26f8 by Melvin Keskin, on behalf of Linus Jahn.
Committed on 06/08/2026 at 12:44.
Pushed by melvo into branch 'master'.

MessageController: Only store stanza ID with expected 'by' attribute

The stored stanza ID is used as an anchor for catching up via MAM.
It will also be used for referencing reported messages by an upcoming
implementation.
To be reliable, only the stanza ID generated by the expected entity is used
(which is the group chat JID for group chat messages and the own account JID
otherwise).

M  +15   -19   src/MessageController.cpp

https://invent.kde.org/network/kaidan/-/commit/41069ebeca7f1627c5b1818a0105c4396dea26f8

diff --git a/src/MessageController.cpp b/src/MessageController.cpp
index 3c2eaf290..8813de2a0 100644
--- a/src/MessageController.cpp
+++ b/src/MessageController.cpp
@@ -515,29 +515,25 @@ void MessageController::handleMessage(const QXmppMessage &msg, MessageOrigin ori
 
     const auto messageId = msg.id();
     const auto stanzaIds = msg.stanzaIds();
-    QString stanzaId;
 
     // Retrieve the appropriate stanza ID.
     //
-    // If the group chat message has multiple stanza IDs, the right stanza ID depending on its
-    // originator is used.
-    // That is needed if the own server archives group chat messages resulting in a second stanza
-    // ID added by the own server to the group chat message.
-    if (receivedFromGroupChat) {
-        const auto itr = std::ranges::find_if(stanzaIds, [senderJid](const QXmppStanzaId &stanzaId) {
-            return stanzaId.by == senderJid;
-        });
+    // Only the stanza ID added by the expected generating entity ("by" attribute) is used. That
+    // way, the stored stanza ID can later be referenced reliably (e.g., for catch-up via MAM or for
+    // spam/abuse reports). For group chat messages, the generating entity JID is the group chat
+    // JID. Otherwise, it is the own account JID (for archived 1:1 messages).
+    const auto generatingEntityJid = receivedFromGroupChat ? senderJid : accountJid;
+    const auto itr = std::ranges::find(stanzaIds, generatingEntityJid, &QXmppStanzaId::by);
 
-        if (itr == stanzaIds.cend()) {
-            // Use the message ID as a fallback for the stanza ID in case the group chat server does
-            // not provide a stanza ID.
-            // That is the case for ejabberd (at least until version 24.10).
-            stanzaId = messageId;
-        } else {
-            stanzaId = itr->id;
-        }
-    } else if (!stanzaIds.isEmpty()) {
-        stanzaId = msg.stanzaIds().first().id;
+    QString stanzaId;
+
+    if (itr != stanzaIds.cend()) {
+        stanzaId = itr->id;
+    } else if (receivedFromGroupChat) {
+        // Use the message ID as a fallback for the stanza ID in case the group chat server does not
+        // provide a stanza ID.
+        // That is the case for ejabberd (at least until version 24.10).
+        stanzaId = messageId;
     }
 
     const auto timestamp = msg.stamp().isValid() ? msg.stamp().toUTC() : QDateTime::currentDateTimeUtc();