From 2785a51916aef6e313ec5ca0e33968cec8ef0100 Mon Sep 17 00:00:00 2001
From: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>
Date: Sun, 22 May 2022 12:51:05 +1000
Subject: [PATCH] Don't pathfind on deleted grid (#8300)

---
 Content.Server/AI/Pathfinding/Accessible/BFSPathfinder.cs | 2 +-
 .../AI/Pathfinding/Pathfinders/AStarPathfindingJob.cs     | 8 +++++++-
 Content.Server/AI/Pathfinding/PathfindingSystem.cs        | 2 +-
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/Content.Server/AI/Pathfinding/Accessible/BFSPathfinder.cs b/Content.Server/AI/Pathfinding/Accessible/BFSPathfinder.cs
index a2fc77ef57..b7a8345aad 100644
--- a/Content.Server/AI/Pathfinding/Accessible/BFSPathfinder.cs
+++ b/Content.Server/AI/Pathfinding/Accessible/BFSPathfinder.cs
@@ -11,7 +11,7 @@ namespace Content.Server.AI.Pathfinding.Accessible
         /// <summary>
         /// Gets all of the tiles in range that can we access
         /// </summary>
-        /// If you want Dikstra then add distances.
+        /// If you want Dijkstra then add distances.
         /// Doesn't use the JobQueue as it will generally be encapsulated by other jobs
         /// <param name="pathfindingArgs"></param>
         /// <param name="range"></param>
diff --git a/Content.Server/AI/Pathfinding/Pathfinders/AStarPathfindingJob.cs b/Content.Server/AI/Pathfinding/Pathfinders/AStarPathfindingJob.cs
index 59679fb8fd..6107c0c4ec 100644
--- a/Content.Server/AI/Pathfinding/Pathfinders/AStarPathfindingJob.cs
+++ b/Content.Server/AI/Pathfinding/Pathfinders/AStarPathfindingJob.cs
@@ -16,17 +16,20 @@ namespace Content.Server.AI.Pathfinding.Pathfinders
         private readonly PathfindingNode? _startNode;
         private PathfindingNode? _endNode;
         private readonly PathfindingArgs _pathfindingArgs;
+        private readonly IEntityManager _entityManager;
 
         public AStarPathfindingJob(
             double maxTime,
             PathfindingNode startNode,
             PathfindingNode endNode,
             PathfindingArgs pathfindingArgs,
-            CancellationToken cancellationToken) : base(maxTime, cancellationToken)
+            CancellationToken cancellationToken,
+            IEntityManager entityManager) : base(maxTime, cancellationToken)
         {
             _startNode = startNode;
             _endNode = endNode;
             _pathfindingArgs = pathfindingArgs;
+            _entityManager = entityManager;
         }
 
         protected override async Task<Queue<TileRef>?> Process()
@@ -44,6 +47,9 @@ namespace Content.Server.AI.Pathfinding.Pathfinders
                 return null;
             }
 
+            if (_entityManager.Deleted(_pathfindingArgs.Start.GridIndex))
+                return null;
+
             var frontier = new PriorityQueue<ValueTuple<float, PathfindingNode>>(new PathfindingComparer());
             var costSoFar = new Dictionary<PathfindingNode, float>();
             var cameFrom = new Dictionary<PathfindingNode, PathfindingNode>();
diff --git a/Content.Server/AI/Pathfinding/PathfindingSystem.cs b/Content.Server/AI/Pathfinding/PathfindingSystem.cs
index e02066638f..37bd2438ff 100644
--- a/Content.Server/AI/Pathfinding/PathfindingSystem.cs
+++ b/Content.Server/AI/Pathfinding/PathfindingSystem.cs
@@ -36,7 +36,7 @@ namespace Content.Server.AI.Pathfinding
         {
             var startNode = GetNode(pathfindingArgs.Start);
             var endNode = GetNode(pathfindingArgs.End);
-            var job = new AStarPathfindingJob(0.003, startNode, endNode, pathfindingArgs, cancellationToken);
+            var job = new AStarPathfindingJob(0.003, startNode, endNode, pathfindingArgs, cancellationToken, EntityManager);
             _pathfindingQueue.EnqueueJob(job);
 
             return job;