From 41c8e382a4da56db4e7f2875cc4d527d734fa7ed Mon Sep 17 00:00:00 2001
From: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>
Date: Tue, 1 Nov 2022 22:50:35 +1100
Subject: [PATCH] Hotfix path empty frontier issue (#12334)

---
 Content.Server/NPC/Pathfinding/PathfindingSystem.AStar.cs | 6 ++++++
 Content.Server/NPC/Pathfinding/PathfindingSystem.BFS.cs   | 6 ++++++
 2 files changed, 12 insertions(+)

diff --git a/Content.Server/NPC/Pathfinding/PathfindingSystem.AStar.cs b/Content.Server/NPC/Pathfinding/PathfindingSystem.AStar.cs
index 366fd8133f..2bc4c60a3c 100644
--- a/Content.Server/NPC/Pathfinding/PathfindingSystem.AStar.cs
+++ b/Content.Server/NPC/Pathfinding/PathfindingSystem.AStar.cs
@@ -30,6 +30,12 @@ public sealed partial class PathfindingSystem
         // Re-validate nodes
         else
         {
+            // Theoretically this shouldn't be happening, but practically...
+            if (request.Frontier.Count == 0)
+            {
+                return PathResult.NoPath;
+            }
+
             (_, currentNode) = request.Frontier.Peek();
 
             if (!currentNode.IsValid())
diff --git a/Content.Server/NPC/Pathfinding/PathfindingSystem.BFS.cs b/Content.Server/NPC/Pathfinding/PathfindingSystem.BFS.cs
index cde593d5a7..3968952965 100644
--- a/Content.Server/NPC/Pathfinding/PathfindingSystem.BFS.cs
+++ b/Content.Server/NPC/Pathfinding/PathfindingSystem.BFS.cs
@@ -25,6 +25,12 @@ public sealed partial class PathfindingSystem
         // Re-validate nodes
         else
         {
+            // Theoretically this shouldn't be happening, but practically...
+            if (request.Frontier.Count == 0)
+            {
+                return PathResult.NoPath;
+            }
+
             (_, currentNode) = request.Frontier.Peek();
 
             if (!currentNode.IsValid())