[Application Development] How can I submit a withdrawal proof myself

[threetoeddinosaur]

Did you check the documentation?

• Yes
• No

Documentation Feedback (Optional)

Unclear on where I can find the required details to make the call proveWithdrawalTransaction on OptimismPortal contract. Also unsure if L2OutputOracle is still a valid Contract

What type of issue are you experiencing?

• Error
• Feature Request
• General Question

Issue Description

I am following the withdrawal flow as given per the documentation but instead of using the sdk for proof submittion, I am submitting the proof myself by making call to this function

function proveWithdrawalTransaction(
        Types.WithdrawalTransaction memory _tx,
        uint256 _disputeGameIndex,
        Types.OutputRootProof calldata _outputRootProof,
        bytes[] calldata _withdrawalProof
    )

of OptimismPortal2 Contract.

I am struggling with and how to achieve the values uint256 _disputeGameIndex,Types.OutputRootProof calldata _outputRootProof and bytes[] calldata _withdrawalProof

Steps to Reproduce

I called the sendMessage function on L2CrossDomainMessenger which internally calls the initializeWithdrawal function of L2ToL1MessageParser contract

Are you using a specific library or SDK?

• OP-SDK
• Viem
• Other
• Not Sure

Are you using the latest version of the library/SDK?

• Yes
• No

Environment Details

No response

Troubleshooting Attempts

No response

What type of support do you need?

• Technical support for issue resolution
• Feature implementation guidance
• General advice or consultation
• Documentation or learning resources

Additional Information

No response

Feedback

No response

[Incede]

One way to get those params would be to use viem op-stack library. I suspect the following code block in this script would get you the needed param(s).

const proveArgs = await publicClientL2.buildProveWithdrawal({
  output,
  withdrawal,
})

[threetoeddinosaur]

@Incede Hey thanks, so I am keen on not using any libraries, what is the workaround to do it without any sdks?

[threetoeddinosaur]

Also viem op-stack is using L2OutputOracle contract but on testnet it is not in use. So I am confused.

[joohhnnn]

Hi there, you can read the source code of VIEM or SDK then build you own script to make the withdraw, there are some clues may give you a help

L2 to L1 Withdrawal Process

Contract Methods

1. L2 Contract: L2_TO_L1_MESSAGE_PASSER

initiateWithdrawal(
    address _target,    // receiving address
    uint256 _gasLimit,  // gas limit
    bytes _data        // additional data
) payable              // withdrawal amount passed via value

2. L1 Contract: PORTAL

proveWithdrawalTransaction(
    WithdrawalTx _tx,          // withdrawal transaction info
    uint256 _l2OutputIndex,    // L2 output index
    OutputRootProof _proof,    // output root proof
    bytes[] _withdrawalProof   // withdrawal proof
)

finalizeWithdrawalTransaction(
    WithdrawalTx _tx           // withdrawal transaction info
)

Process Flow

1. Initiate (on L2)

• User calls L2_TO_L1_MESSAGE_PASSER.initiateWithdrawal()
• Locks funds on L2 and emits a MessagePassed event

2. Prove (on L1)

• After L2 block is finalized on L1
• User proves the withdrawal by submitting proof to PORTAL contract
• Starts challenge period

3. Finalize (on L1)

• After challenge period ends
• User calls PORTAL to finalize and receive funds

These native contract calls complete the withdrawal process from L2 to L1.

[Padraic-O-Mhuiris]

To clarify, is there not an additional call to resolveClaim() and resolve() in the disputeGame? I have a test deployment which use the PermissionedGame as default but it appears by our experiments that this is also required?

[joohhnnn]

If you've enabled Fault Proofs, it means you've also activated the op-challenger component. The op-challenger will handle tasks like resolve() or resolveClaim()operations on your behalf.