I have some code that benchmarks one of my extrinsic.

benchmarks! {
    create_supersig {
        let z in 0 .. 10;

        let alice: T::AccountId = get_account::<T>("ALICE");
        let bob: T::AccountId = get_account::<T>("BOB");
        let charlie: T::AccountId = get_account::<T>("CHARLIE");
        let val: BalanceOf<T> = 4_000_000_000u32.into();
        T::Currency::make_free_balance_be(&alice, val.saturating_mul(4_000_000_000u32.into()));

        let mut vec_members = vec!{(alice.clone(), Role::Standard), (bob, Role::Standard), (charlie, Role::Standard)};
        let oui = "oui";
        for i in 0 .. z {
            let acc = benchmark_account(oui, i, 0);
            vec_members.push((acc, Role::Standard));
        let members: BoundedVec<_, _> = vec_members.try_into().unwrap();
    }: _(RawOrigin::Signed(alice.clone()), members.clone())
    verify {
        assert_eq!(Pallet::<T>::nonce_supersig(), 1);

members is a bounded Vec of the members of the organization I'm creating. The code (and other variations I tried) panic when I try to build the BoundedVec, at:

        let members: BoundedVec<_, _> = vec_members.try_into().unwrap();

If I remove the loop filling the Vec, which means that the bounded Vec will always be the same length (aka the same type), it doesn't panic anymore.

Is it because:

  • I'm not using BoundedVec the right way
  • I cannot use BoundedVec like this in benchmarks (probably due to the work done by the macro)

What should I do?

  1. change the type expected by my extrinsic from BoundedVec to Vec ?
  2. find a way to specify the size/type of my BoundedVec in the benchmarks

It's defined in my pallet config:

    pub trait Config: frame_system::Config {
        /// The maximum number of account that can added or removed in a single call
        type MaxAccountsPerTransaction: Get<u32>;

And use in the extrinsic signature:

        #[pallet::weight(T::WeightInfo::create_supersig(members.len() as u32))]
        pub fn create_supersig(
            origin: OriginFor<T>,
            members: BoundedVec<(T::AccountId, Role), T::MaxAccountsPerTransaction>,
        ) -> DispatchResult {

1 Answer 1


You could use BoundedVec anywhere.

What is the value of MaxAccountsPerTransaction you used in the mock runtime?

If z + 3 > MaxAccountsPerTransaction, then you got this error.

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