(svn r25609) -Fix [FS#5216]: under certain circumstances a track type change would make the end-of-line-is-red setting ineffective

2 files changed, 17 insertions, 1 deletions

diff --git a/src/pathfinder/yapf/yapf_base.hpp b/src/pathfinder/yapf/yapf_base.hpp
index f63dcf04a..0f88d058e 100644
--- a/src/pathfinder/yapf/yapf_base.hpp
+++ b/src/pathfinder/yapf/yapf_base.hpp
@@ -224,6 +224,21 @@ public:
 	}
 
 	/**
+	 * In some cases an intermediate node branch should be pruned.
+	 * The most prominent case is when a red EOL signal is encountered, but
+	 * there was a segment change (e.g. a rail type change) before that. If
+	 * the branch would not be pruned, the rail type change location would
+	 * remain the best intermediate node, and thus the vehicle would still
+	 * go towards the red EOL signal.
+	 */
+	void PruneIntermediateNodeBranch()
+	{
+		while (Yapf().m_pBestIntermediateNode != NULL && (Yapf().m_pBestIntermediateNode->m_segment->m_end_segment_reason & ESRB_CHOICE_FOLLOWS) == 0) {
+			Yapf().m_pBestIntermediateNode = Yapf().m_pBestIntermediateNode->m_parent;
+		}
+	}
+
+	/**
 	 * AddNewNode() - called by Tderived::PfFollowNode() for each child node.
 	 *  Nodes are evaluated here and added into open list
 	 */
diff --git a/src/pathfinder/yapf/yapf_costrail.hpp b/src/pathfinder/yapf/yapf_costrail.hpp
index 44647443b..c6080f2a1 100644
--- a/src/pathfinder/yapf/yapf_costrail.hpp
+++ b/src/pathfinder/yapf/yapf_costrail.hpp
@@ -212,7 +212,8 @@ public:
 						/* we have a red signal in our direction
 						 * was it first signal which is two-way? */
 						if (!IsPbsSignal(sig_type) && Yapf().TreatFirstRedTwoWaySignalAsEOL() && n.flags_u.flags_s.m_choice_seen && has_signal_against && n.m_num_signals_passed == 0) {
-							/* yes, the first signal is two-way red signal => DEAD END */
+							/* yes, the first signal is two-way red signal => DEAD END. Prune this branch... */
+							Yapf().PruneIntermediateNodeBranch();
 							n.m_segment->m_end_segment_reason |= ESRB_DEAD_END;
 							Yapf().m_stopped_on_first_two_way_signal = true;
 							return -1;