Add ERC-4337 bundler RPC client

[ch4r10t33r]

Title

Add ERC-4337 bundler RPC client

Labels

enhancement, account-abstraction, rpc, bundler

Description

Implement RPC client for interacting with ERC-4337 bundlers to submit and manage UserOperations, similar to viem's bundler client.

Requirements

Bundler Namespace

• Create BundlerNamespace similar to existing EthNamespace
• Implement bundler-specific RPC methods:
  • eth_sendUserOperation(userOp: UserOperation, entryPoint: Address) -> Hash
  • eth_estimateUserOperationGas(userOp: UserOperation, entryPoint: Address) -> UserOpGasEstimate
  • eth_getUserOperationByHash(hash: Hash) -> ?UserOperation
  • eth_getUserOperationReceipt(hash: Hash) -> ?UserOperationReceipt
  • eth_supportedEntryPoints() -> []Address

UserOperationReceipt Type

• Define UserOperationReceipt struct with:
  • userOpHash: Hash - UserOperation hash
  • entryPoint: Address - EntryPoint contract used
  • sender: Address - Account that sent the operation
  • nonce: u256 - Nonce used
  • paymaster: ?Address - Paymaster if used
  • actualGasUsed: u256 - Total gas used
  • actualGasCost: u256 - Total gas cost in wei
  • success: bool - Execution status
  • reason: ?[]u8 - Revert reason if failed
  • logs: []Log - Event logs emitted
  • receipt: Receipt - Inner transaction receipt

UserOpGasEstimate

• Define gas estimation result struct:
  • preVerificationGas: u256
  • verificationGasLimit: u256
  • callGasLimit: u256
  • paymasterVerificationGasLimit: ?u256
  • paymasterPostOpGasLimit: ?u256

Error Handling

• Add bundler-specific error types:
  • InvalidUserOp
  • SimulationFailed
  • OpcodeValidationFailed
  • PaymasterRejected
  • AccountNotDeployed

File Location

src/rpc/bundler.zig           # Bundler RPC namespace
src/account_abstraction/
  └── types.zig               # AA-specific types

References

• ERC-4337 Bundler API: https://eips.ethereum.org/EIPS/eip-4337#rpc-methods-eth-namespace
• Viem implementation: https://github.com/wevm/viem/tree/main/src/account-abstraction