From 005892bfdbc997b6eee5b53d08997f7aad1bff5a Mon Sep 17 00:00:00 2001
From: Kuhnovic <68320206+Kuhnovic@users.noreply.github.com>
Date: Sun, 10 Mar 2024 15:37:56 +0100
Subject: [PATCH] Fix #12250: YAPF Trivial rail pathfinding crashes due to
 #12217 (#12258)

---
 src/pathfinder/yapf/yapf_rail.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/pathfinder/yapf/yapf_rail.cpp b/src/pathfinder/yapf/yapf_rail.cpp
index 94ec48f127..2d4c44429a 100644
--- a/src/pathfinder/yapf/yapf_rail.cpp
+++ b/src/pathfinder/yapf/yapf_rail.cpp
@@ -446,6 +446,11 @@ public:
 
 				this->FindSafePositionOnNode(pPrev);
 			}
+
+			/* If the best PF node has no parent, then there is no (valid) best next trackdir to return.
+			 * This occurs when the PF is called while the train is already at its destination. */
+			if (pPrev == nullptr) return INVALID_TRACKDIR;
+
 			/* return trackdir from the best origin node (one of start nodes) */
 			Node &best_next_node = *pPrev;
 			next_trackdir = best_next_node.GetTrackdir();