CatServer/patches/net/minecraft/world/gen/feature/WorldGenShrub.java.patch

--- ../src-base/minecraft/net/minecraft/world/gen/feature/WorldGenShrub.java
+++ ../src-work/minecraft/net/minecraft/world/gen/feature/WorldGenShrub.java
@@ -22,14 +22,14 @@
 
     public boolean generate(World worldIn, Random rand, BlockPos position)
     {
-        for (IBlockState iblockstate = worldIn.getBlockState(position); (iblockstate.getMaterial() == Material.AIR || iblockstate.getMaterial() == Material.LEAVES) && position.getY() > 0; iblockstate = worldIn.getBlockState(position))
+        for (IBlockState iblockstate = worldIn.getBlockState(position); (iblockstate.getBlock().isAir(iblockstate, worldIn, position) || iblockstate.getBlock().isLeaves(iblockstate, worldIn, position)) && position.getY() > 0; iblockstate = worldIn.getBlockState(position))
         {
             position = position.down();
         }
 
-        Block block = worldIn.getBlockState(position).getBlock();
+        IBlockState state = worldIn.getBlockState(position);
 
-        if (block == Blocks.DIRT || block == Blocks.GRASS)
+        if (state.getBlock().canSustainPlant(state, worldIn, position, net.minecraft.util.EnumFacing.UP, ((net.minecraft.block.BlockSapling)Blocks.SAPLING)))
         {
             position = position.up();
             this.setBlockAndNotifyAdequately(worldIn, position, this.woodMetadata);
@@ -50,9 +50,9 @@
                         if (Math.abs(i1) != k || Math.abs(k1) != k || rand.nextInt(2) != 0)
                         {
                             BlockPos blockpos = new BlockPos(l, i, j1);
-                            Material material = worldIn.getBlockState(blockpos).getMaterial();
+                            state = worldIn.getBlockState(blockpos);
 
-                            if (material == Material.AIR || material == Material.LEAVES)
+                            if (state.getBlock().canBeReplacedByLeaves(state, worldIn, blockpos))
                             {
                                 this.setBlockAndNotifyAdequately(worldIn, blockpos, this.leavesMetadata);
                             }
@@ -60,6 +60,9 @@
                     }
                 }
             }
+        // CraftBukkit start - Return false if gen was unsuccessful
+        } else {
+            return false;
         }
 
         return true;