This is completely untested but it probably works. Maybe Fixes #2966

src/main/java/com/gmail/nossr50/skills/herbalism/Herbalism.java

@@ -10,10 +10,12 @@ import com.gmail.nossr50.mcMMO;
 import com.gmail.nossr50.config.AdvancedConfig;
 import com.gmail.nossr50.util.skills.SkillUtils;
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.LinkedHashSet;
 import java.util.List;
 
 public class Herbalism {
+
     public static int farmersDietRankLevel1 = AdvancedConfig.getInstance().getFarmerDietRankChange();
     public static int farmersDietRankLevel2 = farmersDietRankLevel1 * 2;
     public static int farmersDietMaxLevel   = farmersDietRankLevel1 * 5;
@@ -24,80 +26,94 @@ public class Herbalism {
     /**
      * Convert blocks affected by the Green Thumb & Green Terra abilities.
      *
-     * @param blockState The {@link BlockState} to check ability activation for
+     * @param blockState
+     *            The {@link BlockState} to check ability activation for
      * @return true if the ability was successful, false otherwise
      */
     protected static boolean convertGreenTerraBlocks(BlockState blockState) {
         switch (blockState.getType()) {
-            case COBBLE_WALL:
+            case COBBLE_WALL :
                 blockState.setRawData((byte) 0x1);
                 return true;
 
-            case SMOOTH_BRICK:
+            case SMOOTH_BRICK :
                 ((SmoothBrick) blockState.getData()).setMaterial(Material.MOSSY_COBBLESTONE);
                 return true;
 
-            case DIRT:
-            case GRASS_PATH:
+            case DIRT :
+            case GRASS_PATH :
                 blockState.setType(Material.GRASS);
                 return true;
 
-            case COBBLESTONE:
+            case COBBLESTONE :
                 blockState.setType(Material.MOSSY_COBBLESTONE);
                 return true;
 
-            default:
+            default :
                 return false;
         }
     }
-    
-    public static List<Block> findChorusPlant(Block target) {
-        return findChorusPlant(target, true);
+
+    public static HashSet<Block> findChorusPlant(Block target) {
+        return findChorusPlant(target, new HashSet<Block>());
     }
-    
-    private static List<Block> findChorusPlant(Block target, boolean origin) {
-        List<Block> blocks = new ArrayList<Block>();
-        
-        if(target.getType() != Material.CHORUS_PLANT) {
-            return blocks;
+
+    private static HashSet<Block> findChorusPlant(Block target, HashSet<Block> traversed) {
+        if (target.getType() != Material.CHORUS_PLANT) {
+            return traversed;
         }
-        
-        blocks.add(target);
-        
+        // Prevent any infinite loops, who needs more than 64 chorus anyways
+        if (traversed.size() > 64)
+        {
+            return traversed;
+        }
+
+        traversed.add(target);
+
         Block relative = target.getRelative(BlockFace.UP, 1);
-        if(relative.getType() == Material.CHORUS_PLANT) {
-            blocks.addAll(findChorusPlant(relative, false));
+        if (!traversed.contains(relative)) {
+            if (relative.getType() == Material.CHORUS_PLANT) {
+                traversed.addAll(findChorusPlant(relative, traversed));
+            }
         }
-        
-        if(origin || target.getRelative(BlockFace.DOWN, 1).getType() == Material.CHORUS_PLANT) {
-            relative = target.getRelative(BlockFace.NORTH, 1);
-            if(relative.getType() == Material.CHORUS_PLANT) {
-                blocks.addAll(findChorusPlant(relative, false));
+
+        relative = target.getRelative(BlockFace.NORTH, 1);
+        if (!traversed.contains(relative)) {
+            if (relative.getType() == Material.CHORUS_PLANT) {
+                traversed.addAll(findChorusPlant(relative, traversed));
             }
-            
-            relative = target.getRelative(BlockFace.SOUTH, 1);
-            if(relative.getType() == Material.CHORUS_PLANT) {
-                blocks.addAll(findChorusPlant(relative, false));
+        }
+
+        relative = target.getRelative(BlockFace.SOUTH, 1);
+        if (!traversed.contains(relative)) {
+            if (relative.getType() == Material.CHORUS_PLANT) {
+                traversed.addAll(findChorusPlant(relative, traversed));
             }
+        }
 
-            relative = target.getRelative(BlockFace.EAST, 1);
-            if(relative.getType() == Material.CHORUS_PLANT) {
-                blocks.addAll(findChorusPlant(relative, false));
+        relative = target.getRelative(BlockFace.EAST, 1);
+        if (!traversed.contains(relative)) {
+            if (relative.getType() == Material.CHORUS_PLANT) {
+                traversed.addAll(findChorusPlant(relative, traversed));
             }
+        }
 
-            relative = target.getRelative(BlockFace.WEST, 1);
-            if(relative.getType() == Material.CHORUS_PLANT) {
-                blocks.addAll(findChorusPlant(relative, false));
+        relative = target.getRelative(BlockFace.WEST, 1);
+        if (!traversed.contains(relative)) {
+            if (relative.getType() == Material.CHORUS_PLANT) {
+                traversed.addAll(findChorusPlant(relative, traversed));
             }
         }
-        
-        return new ArrayList<Block>(new LinkedHashSet<Block>(blocks));
+
+        return traversed;
     }
 
     /**
-     * Calculate the drop amounts for multi block plants based on the blocks relative to them.
+     * Calculate the drop amounts for multi block plants based on the blocks
+     * relative to them.
      *
-     * @param blockState The {@link BlockState} of the bottom block of the plant
+     * @param blockState
+     *            The {@link BlockState} of the bottom block of the plant
      * @return the number of bonus drops to award from the blocks in this plant
      */
     protected static int calculateMultiBlockPlantDrops(BlockState blockState) {
@@ -105,20 +121,21 @@ public class Herbalism {
         Material blockType = blockState.getType();
         int dropAmount = mcMMO.getPlaceStore().isTrue(block) ? 0 : 1;
 
-        if(blockType == Material.CHORUS_PLANT) {
+        if (blockType == Material.CHORUS_PLANT) {
             dropAmount = 1;
-            
-            if(block.getRelative(BlockFace.DOWN, 1).getType() == Material.ENDER_STONE) {
-                List<Block> blocks = findChorusPlant(block);
-                
+
+            if (block.getRelative(BlockFace.DOWN, 1).getType() == Material.ENDER_STONE) {
+                HashSet<Block> blocks = findChorusPlant(block);
+
                 dropAmount = blocks.size();
-				
-                /*for(Block b : blocks) {
-                    b.breakNaturally();
-                }*/
+
+                /*
+                 * for(Block b : blocks) {
+                 * b.breakNaturally();
+                 * }
+                 */
             }
-        }
-        else {
+        } else {
             // Handle the two blocks above it - cacti & sugar cane can only grow 3 high naturally
             for (int y = 1; y < 3; y++) {
                 Block relativeBlock = block.getRelative(BlockFace.UP, y);
@@ -129,8 +146,7 @@ public class Herbalism {
 
                 if (mcMMO.getPlaceStore().isTrue(relativeBlock)) {
                     mcMMO.getPlaceStore().setFalse(relativeBlock);
-                }
-                else {
+                } else {
                     dropAmount++;
                 }
             }
@@ -142,18 +158,19 @@ public class Herbalism {
     /**
      * Convert blocks affected by the Green Thumb & Green Terra abilities.
      *
-     * @param blockState The {@link BlockState} to check ability activation for
+     * @param blockState
+     *            The {@link BlockState} to check ability activation for
      * @return true if the ability was successful, false otherwise
      */
     protected static boolean convertShroomThumb(BlockState blockState) {
         switch (blockState.getType()) {
-            case DIRT:
-            case GRASS:
-            case GRASS_PATH:
+            case DIRT :
+            case GRASS :
+            case GRASS_PATH :
                 blockState.setType(Material.MYCEL);
                 return true;
 
-            default:
+            default :
                 return false;
         }
     }
@@ -161,7 +178,8 @@ public class Herbalism {
     /**
      * Check if the block has a recently grown crop from Green Thumb
      *
-     * @param blockState The {@link BlockState} to check green thumb regrown for
+     * @param blockState
+     *            The {@link BlockState} to check green thumb regrown for
      * @return true if the block is recently regrown, false otherwise
      */
     public static boolean isRecentlyRegrown(BlockState blockState) {