Fix eth_signTransaction request and response

[alisinabh]

Motivation

As per Ethereum JSON-RPC API Specification, the eth_signTransaction method should return an RLP encoded transaction payload. Anvil is just returning the signature.

Also the parameters of the transaction MUST be part of a sequence.

Solution

This PR returns the signed payload in eth_signTransaction request and also configures the deserializer to deserialize params using a sequence.

A happy path test was also added in tests/it/sign.rs (Was not sure if I should put the test there or in tests/it/transaction.rs)

Thank you!

[alisinabh]

I think there still is a bug (probably in alloy) for signing EIP1559 transactions. The signed result (like the example added here in test) has an invalid y_parity value. It looks like alloy is returning an EIP155 enum value when signing a EIP1559 transaction. For EIP1559, the parity value should be a true/false since chain_id value is already present in the payload.

[alisinabh]

I think there still is a bug (probably in alloy) for signing EIP1559 transactions. The signed result (like the example added here in test) has an invalid y_parity value. It looks like alloy is returning an EIP155 enum value when signing a EIP1559 transaction. For EIP1559, the parity value should be a true/false since chain_id value is already present in the payload.

The change in this PR (alloy-rs/alloy#647) fixes the issue above with signing. I'm not sure if it was the correct place to do that and opened that PR for discussion.

[alisinabh]

Sorry to ping again @DaniPopes. Please let me know if anything else is required and if I can help further with the EIP155 issue in transaction signatures.

[DaniPopes]

thanks, @mattsse ptal