if not game then script = require "test/relative-string" end

local graph = require(script.Parent.graph)
type Node<T> = graph.Node<T>

export type Source<T> = (() -> T) & ((value: T) -> T)

local function sibling<T>(fn: () -> T): (() -> (), T)
    local node = graph.get_scope()
    if not node then error("") end

    local parent_node = node.owner
    if not parent_node then error("") end

    local sibling = graph.create_node(parent_node :: Node<unknown>, false, false)

    graph.push_scope(sibling)

    local ok, result = pcall(fn)

    graph.pop_scope()

    if not ok then error(result, 0) end

    local function destroy()
        graph.destroy(sibling)
    end

    return destroy, result
end

return sibling :: (<T>(fn: () -> T) -> (() -> (), T)) & ((fn: () -> ()) -> () -> ())