fix(MessageList): prevent jump-to-message snap-back from bottom autoscroll (#3109)

Author: MartinCupela

src/components/MessageList/MessageList.tsx

@@ -140,6 +140,7 @@ const MessageListWithContext = (props: MessageListWithContextProps) => {
     [messages],
   );
   const isJumpingToLatest = jumpToLatestPhase !== 'idle';
+  const isHighlightedJumpRequested = !!highlightedMessageId;
   // Highlighted jumps temporarily disable prepend pagination so a target
   // message rendered near the top does not immediately load the previous page.
   const isJumpingToHighlightedMessage = highlightedJumpPhase !== 'idle';
@@ -152,7 +153,8 @@ const MessageListWithContext = (props: MessageListWithContextProps) => {
     scrollToBottom,
     wrapperRect,
   } = useScrollLocationLogic({
-    disableAutoScrollToBottom: isJumpingToLatest || justReachedLatestMergedSet,
+    disableAutoScrollToBottom:
+      isJumpingToLatest || isHighlightedJumpRequested || justReachedLatestMergedSet,
     disableScrollManagement: isJumpingToLatest || isJumpingToHighlightedMessage,
     hasMoreNewer,
     listElement,

src/components/MessageList/hooks/MessageList/useScrollLocationLogic.tsx

@@ -60,6 +60,8 @@ export const useScrollLocationLogic = (params: UseScrollLocationLogicParams) =>
   const closeToTop = useRef(false);
   const previousScrollTopRef = useRef(0);
   const previousMessagesLengthRef = useRef(messages.length);
+  const previousDisableAutoScrollToBottomRef = useRef(disableAutoScrollToBottom);
+  const previousDisableAutoScrollSettleRef = useRef(disableAutoScrollToBottom);
   const anchorRestoreCleanupRef = useRef<(() => void) | null>(null);
 
   const captureAnchor = useCallback(() => {
@@ -249,6 +251,16 @@ export const useScrollLocationLogic = (params: UseScrollLocationLogicParams) =>
    * path where existing viewport position must be preserved.
    */
   useLayoutEffect(() => {
+    const disableAutoScrollJustReleased =
+      previousDisableAutoScrollToBottomRef.current && !disableAutoScrollToBottom;
+    previousDisableAutoScrollToBottomRef.current = disableAutoScrollToBottom;
+
+    // Re-enabling auto-scroll should not immediately force a jump to bottom.
+    // This avoids snap-back after temporary suppression (e.g. jump-to-message).
+    if (disableAutoScrollJustReleased) {
+      return;
+    }
+
     if (listElement) {
       setWrapperRect(listElement.getBoundingClientRect());
     }
@@ -275,6 +287,19 @@ export const useScrollLocationLogic = (params: UseScrollLocationLogicParams) =>
    * to catch late layout updates without keeping the list in a prolonged lock loop.
    */
   useLayoutEffect(() => {
+    const disableAutoScrollJustReleased =
+      previousDisableAutoScrollSettleRef.current && !disableAutoScrollToBottom;
+    previousDisableAutoScrollSettleRef.current = disableAutoScrollToBottom;
+
+    // Skip one settle cycle when auto-scroll suppression is released.
+    // Without this guard, a jump-to-message flow can scroll to the target and then
+    // get pulled back down by the delayed "keep pinned to bottom" retries
+    // (80/260/420/900/1700ms), which looks like a snap-back to the latest message.
+    // Letting this transition frame pass preserves the jump destination.
+    if (disableAutoScrollJustReleased) {
+      return;
+    }
+
     if (
       !listElement ||
       disableAutoScrollToBottom ||