feat: Improve TransferV2 API

contracts/ibc-callbacks/src/contract.rs

@@ -93,9 +93,11 @@ fn execute_transfer(
         }
         ChannelVersion::V2 => {
             let builder = TransferMsgBuilderV2::new(
-                channel_id,
                 to_address.clone(),
                 info.funds.into_iter().map(Into::into).collect(),
+            )
+            .with_direct_transfer(
+                channel_id,
                 IbcTimeout::with_timestamp(env.block.time.plus_seconds(timeout_seconds as u64)),
             );
             match callback_type {

packages/go-gen/tests/cosmwasm_std__IbcMsg.go

@@ -15,19 +15,16 @@ type TransferMsg struct {
 	ToAddress string `json:"to_address"`
 }
 type TransferV2Msg struct {
-	// Existing channel to send the tokens over.
-	ChannelID  string      `json:"channel_id"`
-	Forwarding *Forwarding `json:"forwarding,omitempty"`
 	// An optional memo. See the blog post ["Moving Beyond Simple Token Transfers"](https://medium.com/the-interchain-foundation/moving-beyond-simple-token-transfers-d42b2b1dc29b) for more information.
 	//
 	// There is no difference between setting this to `None` or an empty string.
 	Memo string `json:"memo,omitempty"`
-	// when packet times out, measured on remote chain.
-	Timeout IBCTimeout `json:"timeout"`
 	// Address on the remote chain to receive these tokens.
 	ToAddress string `json:"to_address"`
 	// MsgTransfer in v2 version supports multiple coins.
 	Tokens Array[Coin] `json:"tokens"`
+	// The transfer can be of type: * Direct, * Forwarding, * Forwarding with unwind flag set.
+	TransferType TransferV2Type `json:"transfer_type"`
 }
 type SendPacketMsg struct {
 	ChannelID string `json:"channel_id"`
@@ -102,10 +99,6 @@ type Coin struct {
 	Amount string `json:"amount"`
 	Denom  string `json:"denom"`
 }
-type Forwarding struct {
-	Hops   Array[Hop] `json:"hops"`
-	Unwind bool       `json:"unwind"`
-}
 type Hop struct {
 	ChannelID string `json:"channel_id"`
 	PortID    string `json:"port_id"`
@@ -131,4 +124,27 @@ type IBCTimeoutBlock struct {
 	Height uint64 `json:"height"`
 	// the version that the client is currently on (e.g. after resetting the chain this could increment 1 as height drops to 0)
 	Revision uint64 `json:"revision"`
+}
+type DirectType struct {
+	// Existing channel to send the tokens over.
+	ChannelID string `json:"channel_id"`
+	// When packet times out, measured on remote chain.
+	IBCTimeout IBCTimeout `json:"ibc_timeout"`
+}
+type MultiHopType struct {
+	// Existing channel to send the tokens over.
+	ChannelID string     `json:"channel_id"`
+	Hops      Array[Hop] `json:"hops"`
+	// When packet times out, measured on remote chain. TimestampHeight is not supported in ibc-go Transfer V2.
+	Timeout Uint64 `json:"timeout"`
+}
+type UnwindingType struct {
+	Hops Array[Hop] `json:"hops"`
+	// When packet times out, measured on remote chain. TimestampHeight is not supported in ibc-go Transfer V2.
+	Timeout Uint64 `json:"timeout"`
+}
+type TransferV2Type struct {
+	Direct    *DirectType    `json:"direct,omitempty"`
+	MultiHop  *MultiHopType  `json:"multi_hop,omitempty"`
+	Unwinding *UnwindingType `json:"unwinding,omitempty"`
 }

packages/std/src/ibc.rs

@@ -31,9 +31,35 @@ pub struct Hop {
 
 #[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq, JsonSchema)]
 #[serde(rename_all = "snake_case")]
-pub struct Forwarding {
-    pub unwind: bool,
-    pub hops: Vec<Hop>,
+pub enum TransferV2Type {
+    Direct {
+        /// Existing channel to send the tokens over.
+        channel_id: String,
+        /// When packet times out, measured on remote chain.
+        ibc_timeout: IbcTimeout,
+    },
+    MultiHop {
+        /// Existing channel to send the tokens over.
+        channel_id: String,
+        // A struct containing the list of next hops,
+        // determining where the tokens must be forwarded next.
+        // More info can be found in the `MsgTransfer` IBC docs:
+        // https://ibc.cosmos.network/main/apps/transfer/messages/
+        hops: Vec<Hop>,
+        /// When packet times out, measured on remote chain.
+        /// TimestampHeight is not supported in ibc-go Transfer V2.
+        timeout: Timestamp,
+    },
+    Unwinding {
+        // A struct containing the list of next hops,
+        // determining where the tokens must be forwarded next.
+        // More info can be found in the `MsgTransfer` IBC docs:
+        // https://ibc.cosmos.network/main/apps/transfer/messages/
+        hops: Vec<Hop>,
+        /// When packet times out, measured on remote chain.
+        /// TimestampHeight is not supported in ibc-go Transfer V2.
+        timeout: Timestamp,
+    },
 }
 
 /// These are messages in the IBC lifecycle. Only usable by IBC-enabled contracts
@@ -77,25 +103,21 @@ pub enum IbcMsg {
     /// module to.
     #[cfg(feature = "cosmwasm_3_0")]
     TransferV2 {
-        /// Existing channel to send the tokens over.
-        channel_id: String,
+        /// The transfer can be of type:
+        ///  * Direct,
+        ///  * Forwarding,
+        ///  * Forwarding with unwind flag set.
+        transfer_type: TransferV2Type,
         /// Address on the remote chain to receive these tokens.
         to_address: String,
         /// MsgTransfer in v2 version supports multiple coins.
         tokens: Vec<Coin>,
-        /// when packet times out, measured on remote chain.
-        timeout: IbcTimeout,
         /// An optional memo. See the blog post
         /// ["Moving Beyond Simple Token Transfers"](https://medium.com/the-interchain-foundation/moving-beyond-simple-token-transfers-d42b2b1dc29b)
         /// for more information.
         ///
         /// There is no difference between setting this to `None` or an empty string.
         memo: Option<String>,
-        // A struct containing the list of next hops,
-        // determining where the tokens must be forwarded next.
-        // More info can be found in the `MsgTransfer` IBC docs:
-        // https://ibc.cosmos.network/main/apps/transfer/messages/
-        forwarding: Option<Forwarding>,
     },
     /// Sends an IBC packet with given data over the existing channel.
     /// Data should be encoded in a format defined by the channel version,