How do I check that a part was :Destroy()'ed?

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#1

How do I check that a part was :Destroy()'ed?. Just checking if the part’s Parent is nil doesn’t work because it would also include parts which were parented to nil directly via script.

I could possibly do a check by parenting the part to Lighting (or somewhere else that the player can’t see) and checking if it gets forcefully parented back to nil, but I was hoping that there would be a better way.

If you’re curious, I’m writing a module that generates and maintains list of parts with certain tag(s) (for tag-based ignore lists and whitelists, for example), and I’m wary of cases where parts are recycled.

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#2

There is not a way to do this currently.

1 Like
#3

Okay, it turns out :GetInstanceAddedSignal() fires whenever the part is either is parented to nil or is :Destroy()'ed anyway, so it turns out this isn’t necessary. Huh.

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#4

Here’s a hacky way to do it:

local function Destroyed(x)
	if x.Parent then return false end
	local _, result = pcall(function() x.Parent = x end)
	return result:match("locked") and true or false
end

local x = Instance.new("Part")
print(Destroyed(x)) -- false
x:Destroy()
print(Destroyed(x)) -- true
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Will Mouse.TargetFilter cause Memory Leak?
#5

You can always also just return the boolean of the pcall; I’m not aware of any other errors interrupting reparenting (besides RobloxLocked but that’s evadable on its own).

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#6

If it doesn’t error that its parent is locked then it will error because I’m trying to set its parent to itself.

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#7

I wasn’t aware of such a case erroring, although I’ve probably never tried it myself besides the odd missclick and window popup in Studio.

3 Likes
#8

Another solution is to give it a special tag with CollectionService before being destroyed, and then check if they still have that tag. When a part is destroyed, all its tags are removed. This is also the way to implement a “Destroyed” event, rather than continuously checking if you can still set its parent.

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#9

Couldn’t you just do:

local destroyed = not part:IsDescendantOf(workspace)

EDIT: This check seems to only work on the client, if the :Destroyed was called on the part via server.

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#10

If the part is parented to ReplicatedStorage, then that code wouldn’t work.

If you instead check that it’s a descendant of game (or that its parent is nil), it still wouldn’t work. You can parent things directly to nil and still reparent them back to workspace afterwards, but when you :Destroy() something, you can’t set its parent afterwards anymore.

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#11

What I’m doing in my case is that I’m creating a part on the workspace.

Then on a loop in the client, I’m using that code

to detect if it’s destroyed. It never gets parented to nil or anywhere else besides workspace.

Do you see anything wrong with it?

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#12

Depends how you’re doing the loop. This would be the best.

while true do
    part.AncestryChanged:Wait()
    if not part:IsDescendantOf(game) then
        break
    end
end

-- destroyed at this point

Or you can just connect AncestryChanged itself.

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#13

Why does this work on the client but not on the server?

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#14

It does, what are you detecting?

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#15

Well if something like this works

part.AncestryChanged:connect(function()
if (not part:IsDescendantOf(workspace)) then
end
end)

why would we need this:

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#16

You don’t need that.

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#17

That only detects when the part was parented to nil, not when it’s destroyed.

waffle’s way of checking if a part is destroyed is pretty much the only way.

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#18

No it works when it’s destroyed i just tested it

EDIT: nvm

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#19

How often do you need to know when something is destroyed specifically instead of just when it’s out of the game world?

Inaccurate information

If you truly want a destroyed signal, you can use CollectionService.

CollectionService:AddTag(instance, "__DESTROYED")

…then…

CollectionService:GetInstanceRemovedSignal("__DESTROYED", function(instance)
   -- Called when anything with __DESTROYED is destroyed
end)

To check if it’s destroyed, CollectionService:HasTag(instance, "__DESTROYED").

But you never really need to do that. Again, how often do you need to know when specifically :Destroy() has been called?

2 Likes
#20

So say that my part should only be parented to the workspace, and if it’s not, it’s destroyed in my game (bc I won’t ever parent the part to anything else other than workspace).

So would this code suffice for my scenario?

part.AncestryChanged:connect(function()
if (not part:IsDescendantOf(workspace)) then
--stuff
end
end)
1 Like