MODIFIER_PROPERTY_MODEL_CHANGE caused the game to crash

[bleak moth]

Here is my modifier:

modifier_test = class({})


function modifier_test:OnCreated(table)
    self:GetParent():AddNewModifier(
        self:GetParent(),
        self:GetAbility(),
        "modifier_lich_frostnova_slow",
        { duration = 10 }
    )
end

function modifier_test:DeclareFunctions(self)
    return { MODIFIER_PROPERTY_MODEL_SCALE, MODIFIER_PROPERTY_MODEL_CHANGE }
end

function modifier_test:GetModifierModelChange(self)
    print("model change")
    return "models/heroes/clinkz/clinkz_back_default.vmdl"
end

function modifier_test:GetModifierModelScale(self)
    print("model scale change")
    return 1
end

When I create a unit with this modifier before destroying the fort,the game end then scoreboard is displayed.the modifier('modifier_lich_frostnova_slow') expires and the game crashes. i have already tried remove MODIFIER_PROPERTY_MODEL_CHANGE that the crash fixed. what's the problem.

[bleak pendant]

this property crush game only when model is unavailable

[manic pine]

Why are you passing self into the function? Thats already how class functions work
But yeah dota crashes if you try and set a units model to ones thats undefined, so it clearly doesnt like that model you're trying to use

[bleak moth]

But it only crashes when the modifier it added expires after the game ends. Other times it works well

[manic pine]

Does the game crash if you remove the modifier without the game ending?

[bleak moth]

No ,just wait it expires and destroy

[manic pine]

so its the vanilla modifier that crashing the game, not the modifier that changes the model right?

because if its the vanilla one, why are you using it?

[bleak moth]

The "modifier_lich_frostnova_slow" is a built-in modifier, and replacing it with any other modifier will cause a crash.

This might be intended to understand the cause of crashes related to modifiers, so similar issues can be avoided when creating modifiers in the future.

[verbal grove]

"models/heroes/clinkz/clinkz_back_default.vmdl" doesn't exists in my dota installation and if this model is not your custom one issue probably in that string

You can also try delete "self" from every function args above because this is dota and anything may happen (like idk dota fails to pass self correctly when required and crash)

modifier_test also sounds like something that can be used by valve already (and exists in dota) so try make it name more unique like "modifier_test_custom"

[bleak moth]

alright, I’ll try out your suggestions. ty guys!

[spice hedge]

That is not likely to be the case. No game engine doesn't fail at passing "self" to its own functions.

However, what can happen is that the modifier is removed from game memory while a script is still trying to access it via self (or variable holding self). This is usually handled by IsNull() checks

[verbal grove]

After debugging dedicated server only crashes caused by accessing c++ null entity from lua or random crashes caused by dota failing to call lua ability:GetCastRange correctly (that was fixed by overriding this function with wrapper to match valve args and later broken again because valve pushed fix) i believe something like that can happen

[spice hedge]

Sounds like the order of the arguments broke, rather than self wasn't being passed