Tween:Clone() does not preserve Instance

Bug Reports Engine Bugs
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1

Description

Tween:Clone() does not preserve the Tween’s Instance. A cloned Tween’s Instance will always be nil instead of the Tween’s original Instance. The clone becomes useless since Instance is a read-only property and therefore cannot be set again.

Code example

local TweenService = game:GetService("TweenService")

--// Create a part
local part = Instance.new("Part", workspace)
part.Anchored = true

--// Create a tween
local tween = TweenService:Create(
	part,
	TweenInfo.new(),
	{Position = Vector3.one}
)

--// Clone the tween
local clone = tween:Clone()
print(tween.Instance) -- Part
print(clone.Instance) -- nil

Example place file

This contains the same code as above.

TweenCloneBug.rbxl (49.7 KB)

2

Recreating the tween through TweenService:Create() works around this, but it doesn’t resolve the unexpected cloning behaviour. Is this an intentional limitation of Tween cloning?

2 Likes
3

The cloning issue seems like just an oversight. If it was an intentional limitation, I would expect it to be in the documentation.

4

I’m not 100% sure I follow - is the intended workflow to clone these tweens on the same instance and then you modify them?

To be clear: I believe you are correct that Instance cloning doesn’t work on tweens. But my instinct would be to disable it, not to attempt to fix it, since a lot of tween configuration is constructor-only.

1 Like
5

The one potential useful workflow for cloning Tweens (if they could be cloned properly) is to use each Completed event for connecting different functions. This is the only case I can think of since the properties of Tweens are read-only. However, this could still be accomplished by using :Create() for the same Tween multiple times.

Example:

local TweenService = game:GetService("TweenService")

--// Create a part
local part = Instance.new("Part", workspace)
part.Anchored = true

--// Create a tween
local tween = TweenService:Create(
	part,
	TweenInfo.new(),
	{Position = Vector3.one}
)

--// Functions
function foo(): ()
	print("foo")
end
function bar(): ()
	print("bar")
end

--// Clone and connect functions
local clone = tween:Clone()

tween.Completed:Connect(foo)
clone.Completed:Connect(bar)

--// Play tweens
tween:Play()
task.delay(5, clone.Play, clone)

I thought it was worth a bug report since this behavior isn’t listed anywhere in the documentation. Disabling cloning of Tweens would be a fine fix for this since the only use is extremely situational and probably not worth the effort of fixing.