Program: 22400
Project: 22400
Buggy source:
@SubscribeEvent public void onBlockBreak(BlockEvent.BreakEvent event){
  EntityPlayer player=event.getPlayer();
  Block block=event.block;
  int meta=event.blockMetadata;
  int x=event.x;
  int y=event.y;
  int z=event.z;
  World world=event.world;
  if (player == null) {
    return;
  }
  ItemStack equipped=player.getCurrentEquippedItem();
  if (equipped == null || equipped.getItem() == null || block == null) {
    return;
  }
  if (equipped.getItem() instanceof ItemSteamDrill) {
    ItemSteamDrill drill=(ItemSteamDrill)equipped.getItem();
    ArrayList<Item> upgrades=UtilSteamTool.getHarvestLevelModifiers(equipped);
    if (upgrades != null && drill.isWound(player)) {
      for (      Item upgrade : upgrades) {
        if (upgrade == null) {
          continue;
        }
        if (RecipeHelper.blockMaterials.get(upgrade).right >= block.getHarvestLevel(meta)) {
          block.harvestBlock(world,player,x,y,z,meta);
          world.setBlockToAir(x,y,z);
        }
        event.setCanceled(true);
      }
    }
    if (UtilSteamTool.hasUpgrade(equipped,SteamcraftItems.bigDrill) && drill.isWound(player)) {
      mineExtraBlocks(getExtraBlockCoordinates(sideHit),x,y,z,world,drill,equipped,player);
    }
  }
 else   if (equipped.getItem() instanceof ItemSteamShovel) {
    ItemSteamShovel shovel=(ItemSteamShovel)equipped.getItem();
    if (UtilSteamTool.hasUpgrade(equipped,SteamcraftItems.rotaryBlades) && shovel.isWound(player)) {
      mineExtraBlocks(getExtraBlockCoordinates(sideHit),x,y,z,world,shovel,equipped,player);
    }
  }
}

Fixed version (ground truth):
@SubscribeEvent public void onBlockBreak(BlockEvent.BreakEvent event){
  EntityPlayer player=event.getPlayer();
  Block block=event.block;
  int meta=event.blockMetadata;
  int x=event.x;
  int y=event.y;
  int z=event.z;
  World world=event.world;
  if (player == null) {
    return;
  }
  ItemStack equipped=player.getCurrentEquippedItem();
  if (equipped == null || equipped.getItem() == null || block == null) {
    return;
  }
  if (equipped.getItem() instanceof ItemSteamDrill) {
    ItemSteamDrill drill=(ItemSteamDrill)equipped.getItem();
    ArrayList<Item> upgrades=UtilSteamTool.getHarvestLevelModifiers(equipped);
    if (upgrades != null && drill.isWound(player)) {
      for (      Item upgrade : upgrades) {
        if (upgrade == null) {
          continue;
        }
        if (RecipeHelper.blockMaterials.get(upgrade).right >= block.getHarvestLevel(meta)) {
          block.harvestBlock(world,player,x,y,z,meta);
          world.setBlockToAir(x,y,z);
        }
        event.setCanceled(true);
      }
    }
    if (UtilSteamTool.hasUpgrade(equipped,SteamcraftItems.bigDrill) && drill.isWound(player)) {
      mineExtraBlocks(getExtraBlockCoordinates(sideHit),x,y,z,world,drill,equipped,player);
    }
  }
 else   if (equipped.getItem() instanceof ItemSteamShovel) {
    ItemSteamShovel shovel=(ItemSteamShovel)equipped.getItem();
    if (!shovel.isWound(player)) {
      return;
    }
    if (UtilSteamTool.hasUpgrade(equipped,SteamcraftItems.rotaryBlades)) {
      mineExtraBlocks(getExtraBlockCoordinates(sideHit),x,y,z,world,shovel,equipped,player);
    }
 else     if (UtilSteamTool.hasUpgrade(equipped,SteamcraftItems.gravityDigging)) {
      for (int i=y - Config.gravityDiggingRange; i < y + Config.gravityDiggingRange; i++) {
        if (i < 0) {
          continue;
        }
        Block block1=world.getBlock(x,i,z);
        int meta1=world.getBlockMetadata(x,i,z);
        if (!block1.isToolEffective("String_Node_Str",meta) || !block1.canHarvestBlock(player,meta)) {
          continue;
        }
        if (Item.getItemFromBlock(block) == Item.getItemFromBlock(block1)) {
          world.setBlockToAir(x,i,z);
          block.harvestBlock(world,player,x,i,z,meta1);
        }
      }
    }
  }
}