In Unity 3D, Why Destroy(gameObject) doesn't work here?

Question

I'm making a 3rd person shooter and currently working on projectiles. My projectiles are rigidbodies, and when they are instantiated, they instantiate a geometry according to the weapon used. Anyway, I'm trying to make the projectile destroy itself when it collides but it don't works. Here's the code:

void Update()
{
    if(Physics.CheckSphere(transform.position, 0.5f)) {
        
        Collider[] hitted = Physics.OverlapSphere(transform.position, 0.5f, enemy);
        foreach(var hit in hitted) {
            hit.transform.gameObject.GetComponent<BasicAI>().damage((int)Random.Range(damageAmount[0], damageAmount[1]), sender.transform);
        }

        Destroy(gameObject);
    }        
}

Hope you can help me!

Answer 1

The call to Destroy(gameObject) should work. The dangerous line that stands out to me is

hit.transform.gameObject.GetComponent<BasicAI>().damage((int)Random.Range(damageAmount[0], damageAmount[1]), sender.transform);

If the gameObject doesn't have a BasicAI component, you'll run into a NullReferenceException. This in Unity won't crash your game right there and then. It will however no longer execute the rest of the Update() , and show you an error in the console.

It's tempting to make assumptions about an object having a particular component, upon which you can then call one of its methods. It's probably better to be a bit more defensive. For example, change it to

foreach(var hit in hitted) {
    var basicAI = hit.transform.gameObject.GetComponent<BasicAI>();
    if(basicAI != null)
    {
        basicAI.damage((int)Random.Range(damageAmount[0], damageAmount[1]), sender.transform);
    }
    else
    {
        Debug.LogError("Expected GameObject to have a BasicAI component, but it didn't!");
    }
}

But even if you decide not to do that, pay close attention to your console whenever you encounter strange behaviour like this.