pay dispatch fee at target chain (#911)

* pay dispatch fee at target chain

* refund unspent dispatch weight to messages relayer

* test that transfer actually happens

* pay-at-target-cchain benchmarks + fix previous benchmarks (invalid signature)

* include/exclude pay-dispatch-fee weight from delivery_and_dispatch_fee/delivery tx cost

* remvoe some redundant traces

* enum DispatchFeePayment {}

* typo

* update docs

* (revert removal of valid check)

* Update modules/messages/src/benchmarking.rs

Co-authored-by: Tomasz Drwięga <tomusdrw@users.noreply.github.com>

* Update modules/messages/src/benchmarking.rs

Co-authored-by: Tomasz Drwięga <tomusdrw@users.noreply.github.com>

* Update modules/messages/src/benchmarking.rs

Co-authored-by: Tomasz Drwięga <tomusdrw@users.noreply.github.com>

* Update modules/messages/src/benchmarking.rs

Co-authored-by: Tomasz Drwięga <tomusdrw@users.noreply.github.com>

Co-authored-by: Tomasz Drwięga <tomusdrw@users.noreply.github.com>
Co-authored-by: Tomasz Drwięga <tomasz@parity.io>

bridges/relays/bin-substrate/src/cli/encode_message.rs

@@ -72,7 +72,7 @@ mod tests {
 	#[test]
 	fn should_encode_raw_message() {
 		// given
-		let msg = "01000000e88514000000000002d43593c715fdd31c61141abd04a99fd6822c8558854ccde39a5684e7a56da27d3c040130000000000000000000000000";
+		let msg = "01000000e88514000000000002d43593c715fdd31c61141abd04a99fd6822c8558854ccde39a5684e7a56da27d003c040130000000000000000000000000";
 		let encode_message = EncodeMessage::from_iter(vec!["encode-message", "MillauToRialto", "raw", msg]);
 
 		// when
@@ -101,6 +101,6 @@ mod tests {
 		let hex = encode_message.encode().unwrap();
 
 		// then
-		assert_eq!(format!("{:?}", hex), "0x01000000e88514000000000002d43593c715fdd31c61141abd04a99fd6822c8558854ccde39a5684e7a56da27d3c040130000000000000000000000000");
+		assert_eq!(format!("{:?}", hex), "0x01000000e88514000000000002d43593c715fdd31c61141abd04a99fd6822c8558854ccde39a5684e7a56da27d003c040130000000000000000000000000");
 	}
 }

bridges/relays/bin-substrate/src/cli/send_message.rs

@@ -22,6 +22,7 @@ use crate::cli::{
 	TargetSigningParams,
 };
 use bp_message_dispatch::{CallOrigin, MessagePayload};
+use bp_runtime::messages::DispatchFeePayment;
 use codec::Encode;
 use frame_support::{dispatch::GetDispatchInfo, weights::Weight};
 use relay_substrate_client::{Chain, TransactionSignScheme};
@@ -211,6 +212,7 @@ where
 		spec_version,
 		weight,
 		origin,
+		dispatch_fee_payment: DispatchFeePayment::AtSourceChain,
 		call: HexBytes::encode(call),
 	};
 
@@ -222,12 +224,14 @@ where
 		spec_version,
 		weight,
 		origin,
+		dispatch_fee_payment,
 		call,
 	} = payload;
 	MessagePayload {
 		spec_version,
 		weight,
 		origin,
+		dispatch_fee_payment,
 		call: call.0,
 	}
 }
@@ -268,6 +272,7 @@ mod tests {
 				spec_version: relay_millau_client::Millau::RUNTIME_VERSION.spec_version,
 				weight: 1345000,
 				origin: CallOrigin::SourceAccount(sp_keyring::AccountKeyring::Alice.to_account_id()),
+				dispatch_fee_payment: DispatchFeePayment::AtSourceChain,
 				call: hex!("0401081234").to_vec(),
 			}
 		);
@@ -311,6 +316,7 @@ mod tests {
 					sp_keyring::AccountKeyring::Bob.into(),
 					signature,
 				),
+				dispatch_fee_payment: DispatchFeePayment::AtSourceChain,
 				call: hex!("0701081234").to_vec(),
 			}
 		);

bridges/relays/bin-substrate/src/messages_lane.rs

@@ -204,7 +204,7 @@ mod tests {
 			// reserved for messages dispatch allows dispatch of non-trivial messages.
 			//
 			// Any significant change in this values should attract additional attention.
-			(1024, 216_583_333_334),
+			(814, 216_583_333_334),
 		);
 	}
 }