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In our project, we have on-chain storage items equivalent to the type AuthorityId which is the Public type coming out of the app_crypto! macro in sp-authority-discovery.

We would like to configure the runtime in a way that the <Runtime as frame_system::Config>::AccountId is AuthorityId, because our dispatchable function needs to be able to associate the caller aka origin: OriginFor<T> with the stored AuthorityId.

As the signature check let who = ensure_signed!(origin)?; gives us T::AccountId or concretely <Runtime as frame_system::Config>::AccountId we set type AccountId = AuthorityId in the impl frame_system::Config for Runtime block, which should allow us to make sure that each caller of extrinsics is identified using AuthorityId.

This results in the following:

error[E0599]: the function or associated item `execute_block` exists for struct `Executive<Runtime, Block<Header<u32, BlakeTwo256>, UncheckedExtrinsic<Public, ..., ..., ...>>, ..., ..., ...>`, but its trait bounds were not satisfied
     --> /home/magewe/rust/gensyn/node/chain_node/runtime/src/lib.rs:699:15
      |
  699 |             Executive::execute_block(block);
      |                        ^^^^^^^^^^^^^ function or associated item cannot be called due to unsatisfied trait bounds
      |
     ::: /home/magewe/.cargo/git/checkouts/substrate-7e08433d4c370a21/76fed9b/primitives/runtime/src/generic/unchecked_extrinsic.rs:44:1
      |
  44  | pub struct UncheckedExtrinsic<Address, Call, Signature, Extra>
      | -------------------------------------------------------------- doesn't satisfy `_: Checkable<ChainContext<Runtime>>`
      |
      = note: the full type name has been written to '/home/magewe/rust/gensyn/node/chain_node/target/debug/wbuild/gensyn-runtime/target/wasm32-unknown-unknown/release/deps/gensyn_runtime-13d0535547ae2d3c.long-type-6182207052186516563.txt'
      = note: the following trait bounds were not satisfied:
              `_sp_runtime::generic::UncheckedExtrinsic<sp_authority_discovery::app::Public, RuntimeCall, sp_authority_discovery::app::Signature, (CheckNonZeroSender<Runtime>, CheckSpecVersion<Runtime>, CheckTxVersion<Runtime>, CheckGenesis<Runtime>, CheckEra<Runtime>, CheckNonce<Runtime>, CheckWeight<Runtime>, ChargeTransactionPayment<Runtime>)>: Checkable<ChainContext<Runtime>>`

This indicates to me that using app_crypto! types does not work out of the box here, as the extrinsics do not implement Checkable<_>.

What is the proper way of using types such as AuthorityId as AccountId?

Edit:

Alternatively specifying the associated type as such: type AccountId = <<AuthoritySignature as Verify>::Signer as IdentifyAccound>::AccountId; gives hundreds of errors including the following, potentially more useful error:

error[E0277]: the trait bound `sp_authority_discovery::app::Signature: _sp_runtime::traits::Verify` is not satisfied
     --> /home/magewe/rust/gensyn/node/chain_node/runtime/src/lib.rs:876:3
      |
  876 | /         fn authorities() -> Vec<AuthorityDiscoveryId> {
  877 | |             let current_session_index = <pallet_session_info::Pallet<Runtime>>::session_index();
  878 | |             let earliest_stored_session = <pallet_session_info::Pallet<Runtime>>::earliest_stored_session();
  879 | |
  ...   |
  897 | |
  898 | |         }
      | |_________^ the trait `_sp_runtime::traits::Verify` is not implemented for `sp_authority_discovery::app::Signature`
      |
      = help: the following other types implement trait `_sp_runtime::traits::Verify`:
                AnySignature
                MultiSignature
                sp_core::ecdsa::Signature
                sp_core::ed25519::Signature
                sp_core::sr25519::Signature

Manually implementing Verify here seems weird as I would have expected that a Signature should always be verifiable.

1 Answer 1

4

The solution that works inside the extrinsic is the following:

let who = ensure_signed(origin)?;
let who: AuthorityId = sp_application_crypto::sr25519::Public::from_raw(who.into()).into();

This keeps the AccountId as:

pub type AccountId = <MultiSignature as Verify>::Signer as IdentifyAccount>::AccountId;

I hope this solution is the right way to do the conversion.

If not, please let me know!

1

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