clonefunction

Allocates a new LClosure (or CClosure) that shares the same Proto* pointer and upvalueUpvalueA variable captured from an enclosing scope. When a function references a local variable from an outer function, that variable becomes an upvalue — stored in an UpVal struct that persists even after the outer function returns. references as the original. The clone is a distinct object in the GC but executes identical bytecodeBytecodeThe compiled binary representation of Luau source code. A sequence of 32-bit instructions (opcodes + operands) stored in a Proto's code[] array. Executed by the Luau VM interpreter. and sees identical upvalues. Changes to upvalues via debug.setupvalue affect both the original and the clone.

For Luau closures: the clone gets its own LClosure allocation but the p (proto) and upvals[] pointers are copied by reference, not deep-cloned. This means the clone shares upvalueUpvalueA variable captured from an enclosing scope. When a function references a local variable from an outer function, that variable becomes an upvalue — stored in an UpVal struct that persists even after the outer function returns. slots with the original — both read/write the same UpVal objects.

The primary use is preserving a reference to a function's original behavior before hooking it — unlike hookfunction's trampolineTrampolineA wrapper function that bounces (redirects) calls to another function. In executor context, newcclosure creates a C closure trampoline that calls the Luau function stored in its first upvalue., clonefunction creates a reference that remains valid even if the original is hooked again later.