fix: use Binary as checksum type for InstantiateMsg

ibc-clients/cw-context/src/handlers.rs

@@ -27,7 +27,7 @@ where
 
         let any_consensus_state = Any::decode(&mut msg.consensus_state.as_slice())?;
 
-        self.set_checksum(msg.checksum);
+        self.set_checksum(msg.checksum.to_array()?.into());
 
         client_state.initialise(self, &self.client_id(), any_consensus_state)?;
 

ibc-clients/cw-context/src/types/msgs.rs

@@ -1,7 +1,7 @@
 //! Defines the messages sent to the CosmWasm contract by the 08-wasm proxy
 //! light client.
 use cosmwasm_schema::{cw_serde, QueryResponses};
-use cosmwasm_std::{Binary, Checksum};
+use cosmwasm_std::Binary;
 use ibc_core::client::types::proto::v1::Height as RawHeight;
 use ibc_core::client::types::Height;
 use ibc_core::commitment_types::commitment::{CommitmentPrefix, CommitmentProofBytes};
@@ -20,7 +20,16 @@ use super::error::ContractError;
 pub struct InstantiateMsg {
     pub client_state: Binary,
     pub consensus_state: Binary,
-    pub checksum: Checksum,
+    /// The checksum of the contract.
+    ///
+    /// NOTE: The checksum included in any type of 08-wasm messages, such as
+    /// [`WasmClientState`](ibc_client_wasm_types::client_state::ClientState),
+    /// is hex-encoded bytes. The ibc-go 08-wasm light client initially
+    /// hex-decodes this to a valid checksum. In a subsequent step, the entire
+    /// payload, including the checksum, is base64-encoded by the VM before
+    /// being passed to a CosmWasm contract entry point. Therefore, we use the
+    /// `Binary` type here to properly deserialize a base64-encoded checksum.
+    pub checksum: Binary,
 }
 
 // ------------------------------------------------------------

tests-integration/tests/cosmwasm/helper.rs

@@ -1,7 +1,7 @@
 use std::str::FromStr;
 
 use cosmwasm_std::testing::{message_info, mock_dependencies, mock_env};
-use cosmwasm_std::{coins, Checksum, Env, MessageInfo, Timestamp as CwTimestamp};
+use cosmwasm_std::{coins, Binary, Checksum, Env, MessageInfo, Timestamp as CwTimestamp};
 use ibc::clients::tendermint::types::ConsensusState;
 use ibc::core::primitives::Timestamp as IbcTimestamp;
 use tendermint::Hash;
@@ -13,9 +13,12 @@ pub fn dummy_msg_info() -> MessageInfo {
     message_info(&creator, &coins(1000, "ibc"))
 }
 
-pub fn dummy_checksum() -> Checksum {
-    Checksum::from_hex("2469f43c3ca20d476442bd3d98cbd97a180776ab37332aa7b02cae5a620acfc6")
-        .expect("Never fails")
+pub fn dummy_checksum() -> Binary {
+    let hex_bytes =
+        Checksum::from_hex("2469f43c3ca20d476442bd3d98cbd97a180776ab37332aa7b02cae5a620acfc6")
+            .expect("Never fails");
+
+    hex_bytes.as_slice().into()
 }
 
 pub fn dummy_sov_consensus_state(timestamp: IbcTimestamp) -> ConsensusState {