Program: 187529
Project: 187529
Buggy source:
public void upgrade(ISkillInfo upgrade,boolean quiet){
  if (upgrade instanceof RangedInfo) {
    boolean isPassive=damage <= 0;
    if (getProperties().getValue().containsKey("String_Node_Str")) {
      int damage=((IntTag)getProperties().getValue().get("String_Node_Str")).getValue();
      getProperties().getValue().remove("String_Node_Str");
      DoubleTag doubleTag=new DoubleTag("String_Node_Str",damage);
      getProperties().getValue().put("String_Node_Str",doubleTag);
    }
    if (upgrade.getProperties().getValue().containsKey("String_Node_Str")) {
      if (!upgrade.getProperties().getValue().containsKey("String_Node_Str") || ((StringTag)upgrade.getProperties().getValue().get("String_Node_Str")).getValue().equals("String_Node_Str")) {
        damage+=((DoubleTag)upgrade.getProperties().getValue().get("String_Node_Str")).getValue();
      }
 else {
        damage=((DoubleTag)upgrade.getProperties().getValue().get("String_Node_Str")).getValue();
      }
      if (!quiet) {
        myPet.sendMessageToOwner(MyPetBukkitUtil.setColors(MyPetLocales.getString("String_Node_Str",myPet.getOwner().getLanguage())).replace("String_Node_Str",myPet.getPetName()).replace("String_Node_Str","String_Node_Str" + damage));
      }
    }
    if (upgrade.getProperties().getValue().containsKey("String_Node_Str")) {
      String projectileName=((StringTag)upgrade.getProperties().getValue().get("String_Node_Str")).getValue();
      for (      Projectiles projectile : Projectiles.values()) {
        if (projectile.name().equalsIgnoreCase(projectileName)) {
          selectedProjectile=projectile;
        }
      }
    }
    if (isPassive != (damage <= 0)) {
      if (myPet.getStatus() == PetState.Here) {
        getMyPet().getCraftPet().getHandle().petPathfinderSelector.clearGoals();
        getMyPet().getCraftPet().getHandle().petTargetSelector.clearGoals();
        getMyPet().getCraftPet().getHandle().setPathfinder();
        if (damage == 0) {
          getMyPet().getCraftPet().getHandle().setGoalTarget(null);
        }
      }
    }
  }
}

Fixed version (ground truth):
public void upgrade(ISkillInfo upgrade,boolean quiet){
  if (upgrade instanceof RangedInfo) {
    boolean isPassive=damage <= 0;
    if (upgrade.getProperties().getValue().containsKey("String_Node_Str")) {
      int damage=((IntTag)upgrade.getProperties().getValue().get("String_Node_Str")).getValue();
      upgrade.getProperties().getValue().remove("String_Node_Str");
      DoubleTag doubleTag=new DoubleTag("String_Node_Str",damage);
      upgrade.getProperties().getValue().put("String_Node_Str",doubleTag);
    }
    if (upgrade.getProperties().getValue().containsKey("String_Node_Str")) {
      if (!upgrade.getProperties().getValue().containsKey("String_Node_Str") || ((StringTag)upgrade.getProperties().getValue().get("String_Node_Str")).getValue().equals("String_Node_Str")) {
        damage+=((DoubleTag)upgrade.getProperties().getValue().get("String_Node_Str")).getValue();
      }
 else {
        damage=((DoubleTag)upgrade.getProperties().getValue().get("String_Node_Str")).getValue();
      }
      if (!quiet) {
        myPet.sendMessageToOwner(MyPetBukkitUtil.setColors(MyPetLocales.getString("String_Node_Str",myPet.getOwner().getLanguage())).replace("String_Node_Str",myPet.getPetName()).replace("String_Node_Str","String_Node_Str" + damage));
      }
    }
    if (upgrade.getProperties().getValue().containsKey("String_Node_Str")) {
      String projectileName=((StringTag)upgrade.getProperties().getValue().get("String_Node_Str")).getValue();
      for (      Projectiles projectile : Projectiles.values()) {
        if (projectile.name().equalsIgnoreCase(projectileName)) {
          selectedProjectile=projectile;
        }
      }
    }
    if (isPassive != (damage <= 0)) {
      if (myPet.getStatus() == PetState.Here) {
        getMyPet().getCraftPet().getHandle().petPathfinderSelector.clearGoals();
        getMyPet().getCraftPet().getHandle().petTargetSelector.clearGoals();
        getMyPet().getCraftPet().getHandle().setPathfinder();
        if (damage == 0) {
          getMyPet().getCraftPet().getHandle().setGoalTarget(null);
        }
      }
    }
  }
}