fix: fix deadlock in finding world spawn point

AllayMC · Oct 28, 2024 · 024ec3c · 024ec3c
1 parent 0114e0b
commit 024ec3c
Showing 1 changed file with 14 additions and 10 deletions.
diff --git a/server/src/main/java/org/allaymc/server/world/AllayWorld.java b/server/src/main/java/org/allaymc/server/world/AllayWorld.java
@@ -161,20 +161,24 @@ protected void checkFirstTick() {
         }
         isFirstTick = true;
 
-        // Check spawn point
-        if (!isSafeStandingPos(new Position3i(worldData.getSpawnPoint(), getOverWorld()))) {
-            var newSpawnPoint = getOverWorld().findSuitableGroundPosAround(this::isSafeStandingPos, 0, 0, 32);
-            if (newSpawnPoint == null) {
-                log.warn("Cannot find a safe spawn point in the overworld dimension of world {}", worldData.getName());
-                newSpawnPoint = new Vector3i(0, getOverWorld().getHeight(0, 0) + 1, 0);
-            }
-            worldData.setSpawnPoint(newSpawnPoint);
-        }
-
         if (Server.SETTINGS.worldSettings().loadSpawnPointChunks()) {
             // Add spawn point chunk loader
             getOverWorld().getChunkService().addChunkLoader(new SpawnPointChunkLoader());
         }
+
+        // Shouldn't block world tick poll here, otherwise there will be a deadlock because
+        // Dimension#findSuitableGroundPosAround() -wait-> Dimension#getBlockState() -wait-> ChunkService#getOrLoadChunkSync()
+        // -wait-> WorldGenerator#generateChunk(), and WorldGenerator should be ticked in order to generate chunk normally
+        Thread.ofVirtual().name("World " + worldData.getName() + " Spawn Point Finding Thread").start(() -> {
+            if (!isSafeStandingPos(new Position3i(worldData.getSpawnPoint(), getOverWorld()))) {
+                var newSpawnPoint = getOverWorld().findSuitableGroundPosAround(this::isSafeStandingPos, 0, 0, 32);
+                if (newSpawnPoint == null) {
+                    log.warn("Cannot find a safe spawn point in the overworld dimension of world {}", worldData.getName());
+                    newSpawnPoint = new Vector3i(0, getOverWorld().getHeight(0, 0) + 1, 0);
+                }
+                worldData.setSpawnPoint(newSpawnPoint);
+            }
+        });
     }
 
     protected boolean isSafeStandingPos(Position3ic pos) {