Wormhole Cross-Chain capabilities

[Jorge-Lopes]

Hello Wormhole Team,

Problem Description:

I am currently exploring the cross-chain messaging capabilities of Wormhole, specifically aiming to facilitate interaction between a contract deployed on a Cosmos-based chain and a contract deployed on Solana.
However, I have encountered some questions that are not clearly addressed in the documentation. I would appreciate your insights on the following topics:

1. Handling Message Fee Costs

The documentation refers that the costs of sending a message cross-chain is handled by the MessageSender which will include that required amount on the message as a payment to the relayer.

Although, I have noticed that the quoteCrossChainCost feature is provided by wormhole-solidity-sdk but does not appear to be present in the Rust or TypeScript SDKs implementation.

Can you clarify why this functionality is not available?
What should be the correct flow to estimate and handle message fees in both Solana and Cosmos implementations?

2. Message Receiver Requirements on Solana

From the example provided by wormhole-scaffolding , it seems that the Solana implementation relies on the wormhole_anchor_sdk to validate the authenticity of cross-chain messages by verifying the message VAA.

On the other hand, the same design pattern does not appear to be present in the EVM demo-wormhole-messaging.

Given this difference, what are the specific requirements for a contract deployed on Solana to accept and process messages originating from the Wormhole contract?

3. Testing Environment Limitations

Currently, the publishMessage and verifyMessage methods are not implemented for CosmwasmWormholeCore at the wormhole-sdk-ts. This presents a challenge when testing cross-chain messaging between Cosmos and Solana.

• Is there a plan to implement this feature in the near future?
• If so, when can we expect it to be available, and is there a roadmap or tracking mechanism for its development progress?
• In the absence of these features, are there any alternative approaches you would suggest for testing this implementation?

Any guidance or recommendations on these topics would be greatly appreciated. Thank you for your time and support!