Program: 86713
Project: 86713
Buggy source:
private void player(Player player,String[] args){
  if (args.length == 2) {
    LineTracer tracer=new LineTracer(player);
    Block b=tracer.getTargetBlock();
    if (b != null) {
      Entity mob=Canary.factory().getEntityFactory().newEntity(EntityType.valueOf(args[1].toUpperCase()),b.getLocation());
      mob.spawn();
      player.sendMessage(Colors.YELLOW + Translator.translateAndFormat("String_Node_Str",args[1]));
    }
 else {
      player.notice("String_Node_Str");
    }
  }
  if (args.length == 3) {
    if (args[2].matches("String_Node_Str")) {
      int amount=Integer.parseInt(args[2]);
      LineTracer tracer=new LineTracer(player);
      Block b=tracer.getTargetBlock();
      boolean spawnSuccess=true;
      for (int i=0; i < amount; ++i) {
        if (b != null) {
          Entity e=Canary.factory().getEntityFactory().newEntity(EntityType.valueOf(args[1].toUpperCase()),b.getLocation());
          e.spawn();
        }
 else {
          spawnSuccess=false;
          break;
        }
      }
      if (spawnSuccess) {
        player.sendMessage(Colors.YELLOW + Translator.translateAndFormat("String_Node_Str",args[1]));
      }
 else {
        player.notice(Translator.translate("String_Node_Str"));
      }
    }
 else {
      LineTracer tracer=new LineTracer(player);
      Block b=tracer.getTargetBlock();
      if (b != null) {
        Entity mob=Canary.factory().getEntityFactory().newEntity(EntityType.valueOf(args[1].toUpperCase()),b.getLocation());
        Entity rider=Canary.factory().getEntityFactory().newEntity(EntityType.valueOf(args[2].toUpperCase()));
        mob.spawn(rider);
        player.sendMessage(Colors.YELLOW + Translator.translateAndFormat("String_Node_Str",args[1],args[2]));
      }
    }
  }
  if (args.length == 4) {
    if (!args[3].matches("String_Node_Str")) {
      player.notice(Translator.translate("String_Node_Str"));
      player.notice(Translator.translateAndFormat("String_Node_Str","String_Node_Str"));
      return;
    }
    int amount=Integer.parseInt(args[2]);
    LineTracer tracer=new LineTracer(player);
    Block b=tracer.getTargetBlock();
    boolean spawnSuccess=true;
    if (b != null) {
      for (int i=0; i < amount; ++i) {
        Entity mob=Canary.factory().getEntityFactory().newEntity(EntityType.valueOf(args[1].toUpperCase()),b.getLocation());
        Entity rider=Canary.factory().getEntityFactory().newEntity(EntityType.valueOf(args[2].toUpperCase()));
        mob.spawn(rider);
      }
      if (spawnSuccess) {
        player.sendMessage(Colors.YELLOW + Translator.translateAndFormat("String_Node_Str",args[1],args[2]));
      }
 else {
        player.notice(Translator.translate("String_Node_Str"));
      }
    }
  }
}

Fixed version (ground truth):
private void player(Player player,String[] args){
  if (args.length == 2) {
    LineTracer tracer=new LineTracer(player);
    Block b=tracer.getTargetBlock();
    if (b != null) {
      Entity mob=Canary.factory().getEntityFactory().newEntity(EntityType.valueOf(args[1].toUpperCase()),b.getLocation());
      mob.spawn();
      player.sendMessage(Colors.YELLOW + Translator.translateAndFormat("String_Node_Str",args[1]));
    }
 else {
      player.notice("String_Node_Str");
    }
  }
  if (args.length == 3) {
    if (args[2].matches("String_Node_Str")) {
      int amount=Integer.parseInt(args[2]);
      LineTracer tracer=new LineTracer(player);
      Block b=tracer.getTargetBlock();
      boolean spawnSuccess=true;
      for (int i=0; i < amount; ++i) {
        if (b != null) {
          Entity e=Canary.factory().getEntityFactory().newEntity(EntityType.valueOf(args[1].toUpperCase()),b.getLocation());
          e.spawn();
        }
 else {
          spawnSuccess=false;
          break;
        }
      }
      if (spawnSuccess) {
        player.sendMessage(Colors.YELLOW + Translator.translateAndFormat("String_Node_Str",args[1]));
      }
 else {
        player.notice(Translator.translate("String_Node_Str"));
      }
    }
 else {
      LineTracer tracer=new LineTracer(player);
      Block b=tracer.getTargetBlock();
      if (b != null) {
        Entity mob=Canary.factory().getEntityFactory().newEntity(EntityType.valueOf(args[1].toUpperCase()),b.getLocation());
        Entity rider=Canary.factory().getEntityFactory().newEntity(EntityType.valueOf(args[2].toUpperCase()));
        mob.spawn(rider);
        player.sendMessage(Colors.YELLOW + Translator.translateAndFormat("String_Node_Str",args[1],args[2]));
      }
    }
  }
  if (args.length == 4) {
    if (!args[3].matches("String_Node_Str")) {
      player.notice(Translator.translate("String_Node_Str"));
      Canary.help().getHelp(player,"String_Node_Str");
      return;
    }
    int amount=Integer.parseInt(args[2]);
    LineTracer tracer=new LineTracer(player);
    Block b=tracer.getTargetBlock();
    boolean spawnSuccess=true;
    if (b != null) {
      for (int i=0; i < amount; ++i) {
        Entity mob=Canary.factory().getEntityFactory().newEntity(EntityType.valueOf(args[1].toUpperCase()),b.getLocation());
        Entity rider=Canary.factory().getEntityFactory().newEntity(EntityType.valueOf(args[2].toUpperCase()));
        mob.spawn(rider);
      }
      if (spawnSuccess) {
        player.sendMessage(Colors.YELLOW + Translator.translateAndFormat("String_Node_Str",args[1],args[2]));
      }
 else {
        player.notice(Translator.translate("String_Node_Str"));
      }
    }
  }
}