From 510e80848203ce866a363c465dc775c9c85982cb Mon Sep 17 00:00:00 2001
From: Cecile Tonglet <cecile@parity.io>
Date: Fri, 26 Jun 2020 15:36:03 +0200
Subject: [PATCH] Impl From<UncheckedExtrinsic> for OpaqueExtrinsic (#6522)

---
 substrate/bin/node/cli/src/service.rs         | 12 +++------
 .../src/generic/unchecked_extrinsic.rs        | 27 +++++++++++++++++++
 substrate/primitives/runtime/src/lib.rs       |  9 ++++++-
 3 files changed, 39 insertions(+), 9 deletions(-)

diff --git a/substrate/bin/node/cli/src/service.rs b/substrate/bin/node/cli/src/service.rs
index afc9e23d68..3279490363 100644
--- a/substrate/bin/node/cli/src/service.rs
+++ b/substrate/bin/node/cli/src/service.rs
@@ -424,13 +424,12 @@ mod tests {
 	use node_primitives::{Block, DigestItem, Signature};
 	use node_runtime::{BalancesCall, Call, UncheckedExtrinsic, Address};
 	use node_runtime::constants::{currency::CENTS, time::SLOT_DURATION};
-	use codec::{Encode, Decode};
+	use codec::Encode;
 	use sp_core::{crypto::Pair as CryptoPair, H256};
 	use sp_runtime::{
 		generic::{BlockId, Era, Digest, SignedPayload},
 		traits::{Block as BlockT, Header as HeaderT},
 		traits::Verify,
-		OpaqueExtrinsic,
 	};
 	use sp_timestamp;
 	use sp_finality_tracker;
@@ -605,16 +604,13 @@ mod tests {
 					signer.sign(payload)
 				});
 				let (function, extra, _) = raw_payload.deconstruct();
-				let xt = UncheckedExtrinsic::new_signed(
+				index += 1;
+				UncheckedExtrinsic::new_signed(
 					function,
 					from.into(),
 					signature.into(),
 					extra,
-				).encode();
-				let v: Vec<u8> = Decode::decode(&mut xt.as_slice()).unwrap();
-
-				index += 1;
-				OpaqueExtrinsic(v)
+				).into()
 			},
 		);
 	}
diff --git a/substrate/primitives/runtime/src/generic/unchecked_extrinsic.rs b/substrate/primitives/runtime/src/generic/unchecked_extrinsic.rs
index 41ff2609fc..d16d404ddf 100644
--- a/substrate/primitives/runtime/src/generic/unchecked_extrinsic.rs
+++ b/substrate/primitives/runtime/src/generic/unchecked_extrinsic.rs
@@ -27,6 +27,7 @@ use crate::{
 	},
 	generic::CheckedExtrinsic,
 	transaction_validity::{TransactionValidityError, InvalidTransaction},
+	OpaqueExtrinsic,
 };
 
 const TRANSACTION_VERSION: u8 = 4;
@@ -316,6 +317,23 @@ where
 	}
 }
 
+impl<Address, Call, Signature, Extra> From<UncheckedExtrinsic<Address, Call, Signature, Extra>>
+	for OpaqueExtrinsic
+where
+	Address: Encode,
+	Signature: Encode,
+	Call: Encode,
+	Extra: SignedExtension,
+{
+	fn from(extrinsic: UncheckedExtrinsic<Address, Call, Signature, Extra>) -> Self {
+		OpaqueExtrinsic::from_bytes(extrinsic.encode().as_slice())
+			.expect(
+				"both OpaqueExtrinsic and UncheckedExtrinsic have encoding that is compatible with \
+				raw Vec<u8> encoding; qed"
+			)
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use super::*;
@@ -424,4 +442,13 @@ mod tests {
 		let as_vec: Vec<u8> = Decode::decode(&mut encoded.as_slice()).unwrap();
 		assert_eq!(as_vec.encode(), encoded);
 	}
+
+	#[test]
+	fn conversion_to_opaque() {
+		let ux = Ex::new_unsigned(vec![0u8; 0]);
+		let encoded = ux.encode();
+		let opaque: OpaqueExtrinsic = ux.into();
+		let opaque_encoded = opaque.encode();
+		assert_eq!(opaque_encoded, encoded);
+	}
 }
diff --git a/substrate/primitives/runtime/src/lib.rs b/substrate/primitives/runtime/src/lib.rs
index 881ba3d724..b27cb0c633 100644
--- a/substrate/primitives/runtime/src/lib.rs
+++ b/substrate/primitives/runtime/src/lib.rs
@@ -714,7 +714,14 @@ macro_rules! assert_eq_error_rate {
 /// Simple blob to hold an extrinsic without committing to its format and ensure it is serialized
 /// correctly.
 #[derive(PartialEq, Eq, Clone, Default, Encode, Decode)]
-pub struct OpaqueExtrinsic(pub Vec<u8>);
+pub struct OpaqueExtrinsic(Vec<u8>);
+
+impl OpaqueExtrinsic {
+	/// Convert an encoded extrinsic to an `OpaqueExtrinsic`.
+	pub fn from_bytes(mut bytes: &[u8]) -> Result<Self, codec::Error> {
+		OpaqueExtrinsic::decode(&mut bytes)
+	}
+}
 
 #[cfg(feature = "std")]
 impl parity_util_mem::MallocSizeOf for OpaqueExtrinsic {