Alert Update Crash to Desktop

[dpaulat]

I've experienced a rare (usually no more frequent than once per 24 hours of runtime) crash to desktop with handling of alert updates.

supercell-wx/scwx-qt/source/scwx/qt/model/alert_model.cpp

Lines 410 to 418 in 7f624e1

	std::chrono::system_clock::time_point
	AlertModelImpl::GetEndTime(const types::TextEventKey& key)
	{
	auto messageList = manager::TextEventManager::Instance()->message_list(key);
	auto& lastMessage = messageList.back();
	size_t segmentCount = lastMessage->segment_count();
	auto lastSegment = lastMessage->segment(segmentCount - 1);
	return lastSegment->header_->vtecString_[0].pVtec_.event_end();
	}

When line 415 above is executed, the application may crash if the message list for a key is empty. There should be two fixes:

1. Handle the case if the message list is empty, and return a default value. This will prevent the crash, but still may result in erroneous behavior.
2. Determine why message list is empty. This should never happen for a non-default/valid key.

[dpaulat]

This has not arisen since the original mitigation. Closing, as this no longer appears to be an issue.