Add documentation to SubmitSignedTransaction and actually make it work (#4200)

* Add documentation to signed transactions and actually make them work.

* Fix naming and bounds.

* Forgotten import.

* Remove warning.

* Make accounts optional, fix logic.

* Split the method to avoid confusing type error message.

* Move executor tests to integration.

* Add submit transactions tests.

* Make `submit_transaction` tests compile

* Remove a file that was accidently committed

* Add can_sign helper function.

* Fix compilation.

* Add a key to keystore.

* Fix the tests.

* Remove env_logger.

* Fix sending multiple transactions.

* Remove commented code.

* Bring back criterion.

* Remove stray debug log.

* Apply suggestions from code review

Co-Authored-By: Bastian Köcher <bkchr@users.noreply.github.com>

* Make sure to initialize block correctly.

* Initialize block for offchain workers.

* Add test for transaction validity.

* Fix tests.

* Review suggestions.

* Remove redundant comment.

* Make sure to use correct block number of authoring.

* Change the runtime API.

* Support both versions.

* Bump spec version, fix RPC test.

Co-authored-by: Hernando Castano <HCastano@users.noreply.github.com>
Co-authored-by: Gavin Wood <github@gavwood.com>
Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

substrate/bin/node/runtime/src/lib.rs

@@ -22,7 +22,7 @@
 
 use sp_std::prelude::*;
 use frame_support::{
-	construct_runtime, parameter_types,
+	construct_runtime, parameter_types, debug,
 	weights::Weight,
 	traits::{SplitTwoWays, Currency, Randomness},
 };
@@ -35,7 +35,7 @@ use sp_runtime::{
 use sp_runtime::curve::PiecewiseLinear;
 use sp_runtime::transaction_validity::TransactionValidity;
 use sp_runtime::traits::{
-	self, BlakeTwo256, Block as BlockT, NumberFor, StaticLookup, SaturatedConversion,
+	self, BlakeTwo256, Block as BlockT, StaticLookup, SaturatedConversion,
 	OpaqueKeys,
 };
 use sp_version::RuntimeVersion;
@@ -448,7 +448,8 @@ impl pallet_sudo::Trait for Runtime {
 	type Proposal = Call;
 }
 
-type SubmitTransaction = TransactionSubmitter<ImOnlineId, Runtime, UncheckedExtrinsic>;
+/// A runtime transaction submitter.
+pub type SubmitTransaction = TransactionSubmitter<ImOnlineId, Runtime, UncheckedExtrinsic>;
 
 parameter_types! {
 	pub const SessionDuration: BlockNumber = EPOCH_DURATION_IN_SLOTS as _;
@@ -517,7 +518,11 @@ impl frame_system::offchain::CreateTransaction<Runtime, UncheckedExtrinsic> for
 			.checked_next_power_of_two()
 			.map(|c| c / 2)
 			.unwrap_or(2) as u64;
-		let current_block = System::block_number().saturated_into::<u64>();
+		let current_block = System::block_number()
+			.saturated_into::<u64>()
+			// The `System::block_number` is initialized with `n+1`,
+			// so the actual block number is `n`.
+			.saturating_sub(1);
 		let tip = 0;
 		let extra: SignedExtra = (
 			frame_system::CheckVersion::<Runtime>::new(),
@@ -528,7 +533,9 @@ impl frame_system::offchain::CreateTransaction<Runtime, UncheckedExtrinsic> for
 			pallet_transaction_payment::ChargeTransactionPayment::<Runtime>::from(tip),
 			Default::default(),
 		);
-		let raw_payload = SignedPayload::new(call, extra).ok()?;
+		let raw_payload = SignedPayload::new(call, extra).map_err(|e| {
+			debug::warn!("Unable to create signed payload: {:?}", e);
+		}).ok()?;
 		let signature = TSigner::sign(public, &raw_payload)?;
 		let address = Indices::unlookup(account);
 		let (call, extra, _) = raw_payload.deconstruct();
@@ -649,8 +656,8 @@ impl_runtime_apis! {
 	}
 
 	impl sp_offchain::OffchainWorkerApi<Block> for Runtime {
-		fn offchain_worker(number: NumberFor<Block>) {
-			Executive::offchain_worker(number)
+		fn offchain_worker(header: &<Block as BlockT>::Header) {
+			Executive::offchain_worker(header)
 		}
 	}
 
@@ -750,22 +757,29 @@ impl_runtime_apis! {
 #[cfg(test)]
 mod tests {
 	use super::*;
-	use frame_system::offchain::SubmitSignedTransaction;
-
-	fn is_submit_signed_transaction<T>(_arg: T) where
-		T: SubmitSignedTransaction<
-			Runtime,
-			Call,
-			Extrinsic=UncheckedExtrinsic,
-			CreateTransaction=Runtime,
-			Signer=ImOnlineId,
-		>,
-	{}
+	use frame_system::offchain::{SignAndSubmitTransaction, SubmitSignedTransaction};
 
 	#[test]
-	fn validate_bounds() {
-		let x = SubmitTransaction::default();
-		is_submit_signed_transaction(x);
+	fn validate_transaction_submitter_bounds() {
+		fn is_submit_signed_transaction<T>() where
+			T: SubmitSignedTransaction<
+				Runtime,
+				Call,
+			>,
+		{}
+
+		fn is_sign_and_submit_transaction<T>() where
+			T: SignAndSubmitTransaction<
+				Runtime,
+				Call,
+				Extrinsic=UncheckedExtrinsic,
+				CreateTransaction=Runtime,
+				Signer=ImOnlineId,
+			>,
+		{}
+
+		is_submit_signed_transaction::<SubmitTransaction>();
+		is_sign_and_submit_transaction::<SubmitTransaction>();
 	}
 
 	#[test]