xcvm: change XCVMAck into an enum; and swap values (#3989)

XCVMAck can hold limited set of values (success or failure) so rather
than writing it as a newtype around u8 change it into an enum.  This
simplifies any code that needs to match on an XCVMAck value since it
doesn’t need to check values greater than 1.

Furthermore, rename the variants to Ok and Fail to better fit Rust
naming and be more distinguishable; and swap the value so that Ok is
zero and Fail is one.


Required for merge:
- [x] `pr-workflow-check / draft-release-check` is ✅ success
- Other rules GitHub shows you, or can be read in
[configuration](../terraform/github.com/branches.tf)

Makes review faster:
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clear text to be part of release notes
- [x] I marked PR by `misc` label if it should not be in release notes
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- [x] I was clear on what type of deployment required to release my
changes (node, runtime, contract, indexer, on chain operation, frontend,
infrastructure) if any in PR title or description
- [x] Added reviewer into `Reviewers`
- [ ] I tagged(`@`) or used other form of notification of one person who
I think can handle best review of this PR
- [x] I have proved that PR has no general regressions of relevant
features and processes required to release into production
- [x] Any dependency updates made, was done according guides from
relevant dependency
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example when PR is big)

code/xcvm/cosmwasm/contracts/gateway/src/contract/ibc/one.rs

@@ -112,9 +112,10 @@ pub fn ibc_packet_receive(
 		Ok(SubMsg::reply_always(msg, EXEC_PROGRAM_REPLY_ID))
 	})();
 	Ok(match msg {
-		Ok(msg) => response.set_ack(XCVMAck::OK).add_submessage(msg),
-		Err(err) =>
-			response.add_event(make_ibc_failure_event(err.to_string())).set_ack(XCVMAck::KO),
+		Ok(msg) => response.set_ack(XCVMAck::Ok).add_submessage(msg),
+		Err(err) => response
+			.add_event(make_ibc_failure_event(err.to_string()))
+			.set_ack(XCVMAck::Fail),
 	})
 }
 
@@ -123,14 +124,7 @@ pub fn ibc_packet_ack(_deps: DepsMut, _env: Env, msg: IbcPacketAckMsg) -> Result
 	let ack = XCVMAck::try_from(msg.acknowledgement.data.as_slice())
 		.map_err(|_| ContractError::InvalidAck)?;
 	let _: XcPacket = decode_packet(&msg.original_packet.data).map_err(ContractError::Protobuf)?;
-	match ack {
-		// https://github.com/cosmos/ibc/pull/998
-		XCVMAck::OK => (),
-		XCVMAck::KO => (),
-		_ => return Err(ContractError::InvalidAck),
-	};
-	Ok(IbcBasicResponse::default()
-		.add_event(make_event("ack").add_attribute("ack", ack.value().to_string())))
+	Ok(IbcBasicResponse::default().add_event(make_event("ack").add_attribute("ack", ack)))
 }
 
 #[cfg_attr(not(feature = "library"), cosmwasm_std::entry_point)]

code/xcvm/cosmwasm/contracts/gateway/src/contract/mod.rs

@@ -70,8 +70,8 @@ pub fn reply(deps: DepsMut, _env: Env, msg: Reply) -> Result<Response> {
 fn handle_exec_reply(msg: Reply) -> Result {
 	let (data, event) = match msg.result {
 		SubMsgResult::Ok(_) =>
-			(XCVMAck::OK, make_event("receive").add_attribute("result", "success")),
-		SubMsgResult::Err(err) => (XCVMAck::KO, make_ibc_failure_event(err.to_string())),
+			(XCVMAck::Ok, make_event("receive").add_attribute("result", "success")),
+		SubMsgResult::Err(err) => (XCVMAck::Fail, make_ibc_failure_event(err.to_string())),
 	};
 	Ok(Response::default().add_event(event).set_data(data))
 }

code/xcvm/cosmwasm/tests/src/tests/suite.rs

@@ -769,7 +769,7 @@ mod cross_chain {
 
 		// The relayer must obtain a successful ack on the destination, and nothing on the source
 		// after relaying the ack itself.
-		assert_eq!(relay_data, vec![Some(XCVMAck::OK.into()), None]);
+		assert_eq!(relay_data, vec![Some(XCVMAck::Ok.into()), None]);
 
 		// We don't dispatch any information in the data field.
 		assert_eq!(dispatch_data, None);

code/xcvm/lib/core/src/packet.rs

@@ -1,43 +1,58 @@
 use crate::{Displayed, Funds, UserOrigin};
-use alloc::{vec, vec::Vec};
+use alloc::{string::String, vec::Vec};
 use cosmwasm_std::Binary;
 use parity_scale_codec::{Decode, Encode};
 use scale_info::TypeInfo;
 use serde::{Deserialize, Serialize};
 
-#[derive(Debug, PartialEq, Eq)]
-#[repr(transparent)]
-pub struct XCVMAck(u8);
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+pub enum XCVMAck {
+	Ok,
+	Fail,
+}
 
 impl XCVMAck {
-	pub const KO: XCVMAck = XCVMAck(0);
-	pub const OK: XCVMAck = XCVMAck(1);
-	pub fn into_vec(self) -> Vec<u8> {
-		self.into()
+	fn into_byte(self) -> u8 {
+		match self {
+			Self::Ok => 0,
+			Self::Fail => 1,
+		}
 	}
-	pub fn value(self) -> u8 {
-		self.0
+
+	fn try_from_byte(value: u8) -> Result<Self, ()> {
+		match value {
+			0 => Ok(Self::Ok),
+			1 => Ok(Self::Fail),
+			_ => Err(()),
+		}
 	}
 }
 
 impl From<XCVMAck> for Binary {
 	fn from(value: XCVMAck) -> Self {
-		Binary::from(value.into_vec())
+		Binary::from(Vec::from(value))
 	}
 }
 
 impl From<XCVMAck> for Vec<u8> {
-	fn from(XCVMAck(x): XCVMAck) -> Self {
-		vec![x]
+	fn from(value: XCVMAck) -> Self {
+		[value.into_byte()].to_vec()
+	}
+}
+
+impl From<XCVMAck> for String {
+	fn from(ack: XCVMAck) -> Self {
+		let digit = [b'0' + ack.into_byte()];
+		// SAFETY: digit is always an ASCII digit
+		Self::from(unsafe { core::str::from_utf8_unchecked(&digit[..]) })
 	}
 }
 
 impl TryFrom<&[u8]> for XCVMAck {
 	type Error = ();
 	fn try_from(value: &[u8]) -> Result<Self, Self::Error> {
 		match value {
-			[0] => Ok(XCVMAck::KO),
-			[1] => Ok(XCVMAck::OK),
+			[byte] => Self::try_from_byte(*byte),
 			_ => Err(()),
 		}
 	}