debug.setupvalue

Sets a captured upvalue of a function to a new value.

debug.setupvalue(func: function | number, index: number, value: any): ()

New to upvalues? Learn more here.

Give it a number instead of a function and it targets the closure running at that stack level.

Most commonly used to change a closure’s captured state mid-run - for example, swapping a config table for one that skips a check.

Parameters

Parameter	Type	Description
func	function | number	The closure to change, or a stack level pointing at one.
index	number	Which upvalue to overwrite.
value	any	What to store in the slot.

Returns

void

Aliases

• setupvalue

Example

Jump a closure’s captured counter to any value without calling it that many times.

Example 1

debug.setupvalue(function(...) end, 1, "test")

Give it a number instead of a function and it targets the closure running at that stack level.