Map `ScrollSpecId::Feynman` to `SpecId::Prague`

[greged93]

Currently the Euclid fork maps to the Ethereum Shanghai fork, due to missing EIPs that Scroll doesn't support. Below is an overview of the required work to allow for ScrollSpecId::Feynman to map to the Ethereum Prague fork, which would avoid to much overloading of the revm fork.

Cancun

• EIP-1153: Transient storage opcodes → already active for Scroll since Curie.
• EIP-5656: MCOPY - Memory copying instruction → already active for Scroll since Curie.
• EIP-4788: Beacon block root in the EVM → would be implemented in Reth, so activating it should not influence the behavior of Revm.
• EIP-4844: Shard Blob Transactions → Would require setting the blob_excess_gas_and_price field of the BlockEnv to Some(0), and would activate EIP-4844 transactions in revm. If we prevent these transactions at mempool level and validate their absence at block validation level, this should be acceptable. This is similar to what OP does.
• EIP-6780: SELFDESTRUCT only in same transaction → NOT ACTIVE
• EIP-7516: BLOBBASEFEE opcode → NOT ACTIVE

Shanghai

• EIP-7702: Set EOA account code → already active for Scroll since Euclid.
• EIP-2537: Precompile for BLS12-381 curve operations → NOT ACTIVE
• EIP-7623: Increase calldata cost → planned for Feynman.
• EIP-2935: Save historical block hashes in state → would be implemented in Reth, so activating it should not influence the behavior of revm.

Changes required in revm

• Map Feynman to Prague
• Deactivate BLOBBASEFEE from the instructions.
• Deactivate BLS12-381 from precompiles.

Changes required in Reth

• Set blob_excess_gas_and_price to Some(0) in all places that prepare a BlockEnv. Similar to the ConfigureEvm implementation to Op.

[Thegaram]

So we can do this, even though we won't support the BLS precompiles?

[greged93]

So we can do this, even though we won't support the BLS precompiles?

I think it's more a notion of definition, because code wise I couldn't find anything that would prevent us from just activating PRAGUE and disabling any opcode or precompile that we don't want to support (neither from revm nor Reth).

I think if we want to do this we would probably do it in the correct way, as OP did, meaning also setting the blobGasUsed and excessBlobGas fields on blocks, setting them to 0.