Fix a dupe bug that resulted from yet another change to piston code a couple mc patches ago. Oh well.

src/main/java/com/gmail/nossr50/listeners/BlockListener.java

@@ -67,24 +67,15 @@ public class BlockListener implements Listener {
     @EventHandler(priority = EventPriority.MONITOR, ignoreCancelled = true)
     public void onBlockPistonExtend(BlockPistonExtendEvent event) {
         BlockFace direction = event.getDirection();
-        Block futureEmptyBlock = event.getBlock().getRelative(direction); // Block that would be air after piston is finished
+        Block movedBlock = event.getBlock();
+        movedBlock = movedBlock.getRelative(direction, 2);
 
-        if (futureEmptyBlock.getType() == Material.AIR) {
-            return;
-        }
-
-        List<Block> blocks = event.getBlocks();
-
-        for (Block b : blocks) {
+        for (Block b : event.getBlocks()) {
             if (BlockUtils.shouldBeWatched(b.getState()) && mcMMO.getPlaceStore().isTrue(b)) {
-                Block nextBlock = b.getRelative(direction);
-                mcMMO.getPlaceStore().setTrue(nextBlock);
-                //b.getRelative(direction).setMetadata(mcMMO.blockMetadataKey, mcMMO.metadataValue);
+                movedBlock = b.getRelative(direction);
+                mcMMO.getPlaceStore().setTrue(movedBlock);
             }
         }
-
-        // Needed because blocks sometimes don't move when two pistons push towards each other
-        //new PistonTrackerTask(blocks, direction, futureEmptyBlock).runTaskLater(plugin, 2);
     }
 
     /**
@@ -94,36 +85,15 @@ public class BlockListener implements Listener {
      */
     @EventHandler(priority = EventPriority.MONITOR, ignoreCancelled = true)
     public void onBlockPistonRetract(BlockPistonRetractEvent event) {
-        // event.isSticky() always returns false
-        // if (!event.isSticky()){
-        //     return;
-        // }
-
-        // Sticky piston return PISTON_MOVING_PIECE and normal piston PISTON_BASE
-        if (event.getBlock().getType() != Material.PISTON_MOVING_PIECE) {
-            return;
-        }
-
         // Get opposite direction so we get correct block
-        BlockFace direction = event.getDirection().getOppositeFace();
+        BlockFace direction = event.getDirection();
         Block movedBlock = event.getBlock().getRelative(direction);
         mcMMO.getPlaceStore().setTrue(movedBlock);
 
-        // If we're pulling a slime block, it might have something attached to it!
-        if (movedBlock.getRelative(direction).getState().getType() == Material.SLIME_BLOCK) {
-            for (Block block : event.getBlocks()) {
-                movedBlock = block.getRelative(direction);
-                mcMMO.getPlaceStore().setTrue(movedBlock);
-//            // Treat the slime blocks as if it is the sticky piston itself, because pulling
-//            // a slime block with a sticky piston is effectively the same as moving a sticky piston.
-               // new StickyPistonTrackerTask(direction, event.getBlock(), block).runTaskLater(plugin, 2);
-            }
-
-            return;
+        for (Block block : event.getBlocks()) {
+            movedBlock = block.getRelative(direction);
+            mcMMO.getPlaceStore().setTrue(movedBlock);
         }
-
-        // Needed only because under some circumstances Minecraft doesn't move the block
-        //new StickyPistonTrackerTask(direction, event.getBlock(), movedBlock).runTaskLater(plugin, 2);
     }
 
     /**