Fixed extrinsic encoding

core/sr-primitives/src/generic/unchecked_extrinsic.rs

@@ -103,9 +103,9 @@ where
 	fn decode<I: Input>(input: &mut I) -> Option<Self> {
 		// This is a little more complicated than usual since the binary format must be compatible
 		// with substrate's generic `Vec<u8>` type. Basically this just means accepting that there
-		// will be a prefix of u32, which has the total number of bytes following (we don't need
+		// will be a prefix of vector length (we don't need
 		// to use this).
-		let _length_do_not_remove_me_see_above: u32 = Decode::decode(input)?;
+		let _length_do_not_remove_me_see_above: Vec<()> = Decode::decode(input)?;
 
 		Some(UncheckedExtrinsic {
 			signature: Decode::decode(input)?,
@@ -125,15 +125,14 @@ where
 	fn encode(&self) -> Vec<u8> {
 		let mut v = Vec::new();
 
-		// need to prefix with the total length as u32 to ensure it's binary comptible with
-		// Vec<u8>. we'll make room for it here, then overwrite once we know the length.
-		v.extend(&[0u8; 4]);
-
 		self.signature.encode_to(&mut v);
 		self.function.encode_to(&mut v);
 
-		let length = (v.len() - 4) as u32;
-		length.using_encoded(|s| v[0..4].copy_from_slice(s));
+		// need to prefix with the total length to ensure it's binary comptible with
+		// Vec<u8>.
+		let mut length: Vec<()> = Vec::new();
+		length.resize(v.len(), ());
+		length.using_encoded(|s| { v.splice(0..0, s.iter().cloned()); });
 
 		v
 	}
@@ -150,3 +149,20 @@ impl<Address, Index, Call, Signature> fmt::Debug for UncheckedExtrinsic<Address,
 		write!(f, "UncheckedExtrinsic({:?}, {:?})", self.signature.as_ref().map(|x| (&x.0, &x.2)), self.function)
 	}
 }
+
+#[cfg(test)]
+mod test {
+	use codec::{Decode, Encode};
+	use super::UncheckedExtrinsic;
+
+	#[test]
+	fn encoding_matches_vec() {
+		type Extrinsic = UncheckedExtrinsic<u32, u32, u32, u32>;
+		let ex = Extrinsic::new_unsigned(42);
+		let encoded = ex.encode();
+		let decoded = Extrinsic::decode(&mut encoded.as_slice()).unwrap();
+		assert_eq!(decoded, ex);
+		let as_vec: Vec<u8> = Decode::decode(&mut encoded.as_slice()).unwrap();
+		assert_eq!(as_vec.encode(), encoded);
+	}
+}

core/sr-primitives/src/generic/unchecked_mortal_extrinsic.rs

@@ -113,9 +113,9 @@ where
 	fn decode<I: Input>(input: &mut I) -> Option<Self> {
 		// This is a little more complicated than usual since the binary format must be compatible
 		// with substrate's generic `Vec<u8>` type. Basically this just means accepting that there
-		// will be a prefix of u32, which has the total number of bytes following (we don't need
+		// will be a prefix of vector length (we don't need
 		// to use this).
-		let _length_do_not_remove_me_see_above: u32 = Decode::decode(input)?;
+		let _length_do_not_remove_me_see_above: Vec<()> = Decode::decode(input)?;
 
 		let version = input.read_byte()?;
 
@@ -143,10 +143,6 @@ where
 	fn encode(&self) -> Vec<u8> {
 		let mut v = Vec::new();
 
-		// need to prefix with the total length as u32 to ensure it's binary comptible with
-		// Vec<u8>. we'll make room for it here, then overwrite once we know the length.
-		v.extend(&[0u8; 4]);
-
 		// 1 byte version id.
 		match self.signature.as_ref() {
 			Some(s) => {
@@ -159,8 +155,11 @@ where
 		}
 		self.function.encode_to(&mut v);
 
-		let length = (v.len() - 4) as u32;
-		length.using_encoded(|s| v[0..4].copy_from_slice(s));
+		// need to prefix with the total length to ensure it's binary comptible with
+		// Vec<u8>.
+		let mut length: Vec<()> = Vec::new();
+		length.resize(v.len(), ());
+		length.using_encoded(|s| { v.splice(0..0, s.iter().cloned()); });
 
 		v
 	}
@@ -275,4 +274,14 @@ mod tests {
 		assert!(ux.is_signed());
 		assert_eq!(<Ex as Checkable<TestContext>>::check(ux, &TestContext), Err("bad signature in extrinsic"));
 	}
-}
+
+	#[test]
+	fn encoding_matches_vec() {
+		let ex = Ex::new_unsigned(DUMMY_FUNCTION);
+		let encoded = ex.encode();
+		let decoded = Ex::decode(&mut encoded.as_slice()).unwrap();
+		assert_eq!(decoded, ex);
+		let as_vec: Vec<u8> = Decode::decode(&mut encoded.as_slice()).unwrap();
+		assert_eq!(as_vec.encode(), encoded);
+	}
+}

node/executor/src/lib.rs

@@ -312,7 +312,7 @@ mod tests {
 		construct_block(
 			2,
 			block1(false).1,
-			hex!("703efd5294ae5677c3c975593c64796cce27b471f27936c0cf31fda0a55ede19").into(),
+			hex!("022372996f312fc57b4649a8e3427a989803652d6d08735f4e4c8510f6b89ff8").into(),
 			None,
 			vec![
 				CheckedExtrinsic {