When to check if entity is valid?

[raulitop]

This thread is to talk about when is a must to check if entity is valid.

For example, I see on many plugins that check if entity is valid inside:

• Fakemeta hooks like FM_ShouldCollide.
• Hamsandwich hooks like Ham_Item_AddToPlayer.
• Engine hooks like register_touch.

Is this check necessary?
I'm trying to achieve remove unnecessary calls to pev_valid or similars like is_nullent introduced on ReAPI.

I'm talking about this:

register_forward(FM_ShouldCollide, "fw_ShouldCollide");

public fw_ShouldCollide(playerindex, entindex) {
    if( !pev_valid(playerindex) || !pev_valid(entindex) )
        return FMRES_IGNORED;
    
    // continue code....
}

 

[raulitop]

This is the maximum information I have found:

https://forums.alliedmods.net/showthread.php?t=90710

https://forums.alliedmods.net/showthread.php?t=291997

Just explains how are the natives working, but not about when we must use it.

 

[fl0wer]

raulitop, entity can be removed and you get invalid entity in next function inside frame.

 

[raulitop]

raulitop, entity can be removed and you get invalid entity in next function inside frame.

Well, that doesn't quite answer the question.
That could be a reason to check if you have some plugins interacting, like this dude: https://forums.alliedmods.net/showthread.php?t=302217

So basically every single time that ent touches me, it gets destroyed, then it triggers the FM_Touch in my other plugin and causes invalid entity errors for pev().

I remember to read one comment from @PRoSToTeM@ (don't know his name here) saying on hamsandwich hooks, the entity is already verifyed to be valid.
Now I only found this comment: https://forums.alliedmods.net/showthread.php?p=2535131#post2535131

if(pev_valid(iWeapon) >= 2) is not need here.

 

[mlibre]

In some cases I've seen they tend to skip the call to native, they just check to see if it returns null.

if( !playerindex || !entindex )
        return FMRES_IGNORED;

 

[bizon]

Вы занимаетесь слишком усердной оптимизацией.
Добавляйте проверку is_nullent в описанных вами событиях, чтобы быть уверенным в том, что работа каких-то плагинов не приведёт к падению сервера.
Нагрузки вы не увидите из-за этой функции.

17 Мар 2024

mlibre, некоторые null возвращают -1. Так что логичнее проверять < 0. Хотя тоже сомнительно это.

17 Мар 2024

И, в конце концов, используйте уже ReAPI.

 

[raulitop]

Вы занимаетесь слишком усердной оптимизацией.
Добавляйте проверку is_nullent в описанных вами событиях, чтобы быть уверенным в том, что работа каких-то плагинов не приведёт к падению сервера.

This thread is not about optimization, it's about doing things correctly.

For example, on my tests I checked Hamsandwich hooks call always valid entities.
So, we can avoid the valid entity check here, is redundant.

But I have the doubt about Fakemeta and Engine hooks.

 

[mlibre]

on my tests I checked Hamsandwich hooks call always valid entities.
So, we can avoid the valid entity check here, is redundant.

this means that in all RegisterHams this can be omitted?

 

[fl0wer]

mlibre, yes, but if you remove_entity (not FL_KILLME) in pre and do something in post it's was error.