We don't scroll to some newly arrived messages

[WofWca]

• Operating System (Linux/Mac/Windows/iOS/Android): All

• Delta Chat Version: 1.48.0

• Expected behavior: No matter what message shows up in a chat, we should scroll to it (as long as we're scrolled to the bottom, of course)

• Actual behavior: The scroll position remains where it was and you have to scroll to the new message

• Steps to reproduce the problem:

  1. Open a chat with someone
  2. Send a .xdc (webxdc) app.
  3. Open that app and open the dev tools for the app.
  4. Type

     webxdc.sendUpdate({
         payload: null,
         info: 'test',
     }, '')

• Screenshots:

  2024-11-09-yx3KMpXLVI.mp4

• Logs:

The above reproduction steps also work for when the info message is triggered by other chat members.

As was discussed in a chat today, some messages do not trigger the IncomingMsg event. Then only trigger MsgsChanged But currently the IncomingMsg event is what we're listening on to scroll to new messages:

deltachat-desktop/packages/frontend/src/stores/messagelist.ts

Lines 65 to 73 in c28d796

	onDCEvent(accountId, 'IncomingMsg', ({ chatId: eventChatId }) => {
	if (chatId === eventChatId) {
	store.effect.onEventIncomingMessage()
	} else {
	store.log.debug(
	`chatId of IncomingMsg event (${chatId}) doesn't match id of selected chat (${eventChatId}). Skipping.`
	)
	}
	}),

deltachat-desktop/packages/frontend/src/stores/chat/chat_view_reducer.ts

Lines 92 to 106 in c28d796

	static fetchedIncomingMessages(prevState: ChatViewState): ChatViewState {
	const {
	lastKnownScrollHeight,
	// lastKnownScrollTop,
	} = getLastKnownScrollPosition()
	return {
	...prevState,
	scrollTo: {
	type: 'scrollToBottom',
	ifClose: true,
	},
	lastKnownScrollHeight,
	}
	}

So, as was suggested by @link2xt and @r10s, we probably need to rewrite the code that updates viewState, to update viewState based on actual changes to the array of messages, and not just events, to catch all such cases.

Related older issues: #1783, #1793,