feat: ChunkStreamer tracks failed chunks to prevent retry storms

VoxelEngine.Tests/Streaming/ChunkStreamerTests.cs

@@ -317,4 +317,38 @@ public class ChunkStreamerTests
         // Only the chunk in the load box was created; no spurious remesh.
         Assert.Single(created);
     }
+
+    [Fact]
+    public void Tick_GeneratorThrows_LogsAndDoesNotRetry()
+    {
+        var cfg = new Configuration
+        {
+            RenderDistanceHorizontal = 0,
+            RenderDistanceVertical = 0,
+            MaxGenerateJobsInFlight = 100,
+            MaxMeshUploadsPerFrame = 100,
+        };
+        var registry = new BlockRegistry();
+        var store = new InMemoryChunkModificationStore();
+        var world = new World.World(registry, store);
+        var mesher = new FakeMesher();
+        var executor = new SynchronousJobExecutor();
+        int generateCalls = 0;
+        Func<Vector3i, VoxelChunk> generate = _ =>
+        {
+            generateCalls++;
+            throw new InvalidOperationException("boom");
+        };
+        Func<float[], IChunkRenderer> factory = m => new FakeRenderer(m);
+
+        var streamer = new ChunkStreamer(cfg, world, generate, mesher, registry, executor, factory);
+
+        streamer.Tick(new Vector3i(0, 0, 0));
+        Assert.Equal(1, generateCalls);
+        Assert.False(streamer.IsReady(new Vector3i(0, 0, 0)));
+
+        // Tick again — same chunk, same position. Should NOT call generate again.
+        streamer.Tick(new Vector3i(0, 0, 0));
+        Assert.Equal(1, generateCalls);
+    }
 }

World/Streaming/ChunkStreamer.cs

@@ -29,6 +29,7 @@ public sealed class ChunkStreamer : IDisposable
     private readonly PriorityQueue<Vector3i, int> _pendingLoad = new();
     private readonly ConcurrentQueue<ChunkJobResult> _completed = new();
     private readonly Queue<Vector3i> _pendingUnload = new();
+    private readonly HashSet<Vector3i> _failed = new();
 
     private Vector3i _lastPlayerChunk = new(int.MinValue, int.MinValue, int.MinValue);
     private int _inFlight;
@@ -118,6 +119,7 @@ public sealed class ChunkStreamer : IDisposable
 
         foreach (var pos in target)
         {
+            if (this._failed.Contains(pos)) continue;
             if (this._tracked.Add(pos))
             {
                 int priority = (pos.X - p.X) * (pos.X - p.X)
@@ -162,6 +164,7 @@ public sealed class ChunkStreamer : IDisposable
             }
             this._world.RemoveChunk(pos);
             this._ready.Remove(pos);
+            this._failed.Remove(pos);
             Log.Debug("Unloaded {Pos}", pos);
         }
     }
@@ -190,6 +193,7 @@ public sealed class ChunkStreamer : IDisposable
     {
         if (result.Error != null || result.Mesh == null)
         {
+            this._failed.Add(result.Pos);
             Log.Error(result.Error, "Chunk {Pos} failed to load", result.Pos);
             return;
         }