[OP Stack Deployment] - op-stack on alt-da mode + withdrawal from L2

[tiagorvmartins]

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• Yes

Did you check for duplicate questions?

• Yes

Issue Description

I am currently trying to deploy an op-stack layer 2 on alt-da mode rolling up to sepolia on l1, however I am currently not able to do withdrawals after a successful deposit L1 -> L2.

This might be related to the fact that Fault Proofs are still no available on alt-da mode, correct?

When following the tutorial guide on viem op-stack docs for the withdrawal process, the following step fails:

const { output, withdrawal } = await publicClientL1.waitToProve({
        receipt: withdrawalReceipt,
        targetChain: walletClientL2.chain
});

While debugging the code it seems like, there are no previous 'games' and thus it fails doing so.
Having said this, I would like to get an answer to the following questions:

1. when running optimism with alt-da, are withdrawals still possible to do since Fault Proof System is not there yet (according to the optimism docs) and the only thing being posted to L1 are commitments ?

2. if answer to question above is affirmative, how can I then do an withdrawal from L2 when running op-stack with alt-da?

3. In case the answer to first question and second question are positive, then if the DA layer that holds all the transaction data is lost by disaster reason or something else, are withdraws (like emergency exits) on L1 still possible even though the L2 DA layer is lost? Could the escape hatch such as a Forced Transaction mechanism help here recovering something that was on L2, like a account native token?

Answers to the questions above would be greatly appreciated!
Thank you in advance!

Logs

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Additional Information

Currently running:

op-node/v1.9.1
op-proposer/v1.9.1
op-batcher/v1.9.1
op-alt-da/v1.9.1
op-geth/latest

Added on getting-started.json while deploying the contracts.

"proofMaturityDelaySeconds": 12,
"disputeGameFinalityDelaySeconds": 6,
"respectedGameType": 254,
"useFaultProofs": true,
"useAltDA": true,
"daCommitmentType": "KeccakCommitment",
"daChallengeWindow": 16,
"daResolveWindow": 16,
"daBondSize": 1000000,
"daResolverRefundPercentage": 0

Feedback

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[hash1go]

Hello, I just wanted to confirm—have you also posted the same question in the OP Stack channel on Discord?

[tiagorvmartins]

Yes I did that previously, gonna add here the details provided by you.

Answered by @hash1go :

Even in Alt-DA mode without fault proofs, withdrawals to L1 are possible.
Furthermore, even if the DA layer loses data, as long as Layer 2 can continue posting state roots to L1, withdrawals are theoretically possible. However, in such cases, the validity of withdrawals can no longer be objectively verified by third parties.

In the absence of fault proofs, whether or not Alt-DA is used should not affect withdrawals to L1.
It only involves proving onchain that a withdrawal transaction to L1 was executed based on the state root submitted to L1.

The disputegame contract and the factory contract used to create it are related to fault proofs and are not used on L2s that do not have fault proofs. On L2s where fault proofs are enabled, output proposals are made to L1 via the disputegame factory contract.

However, in the absence of fault proofs, output proposals should be made by the L2Output Oracle. An error stating that the disputegame contract does not exist suggests there may be an issue with the setup.
That said, I do not have experience setting up an L2 with Alt-DA enabled, so I am not familiar with the specific setup process.

The op-challenger is also a component related to fault proofs and should not be necessary on L2s without fault proofs.

I understand that the Optimism SDK has been deprecated and integrated into viem, but I don’t know how on-chain proofs for L1 withdrawals were created when the Optimism SDK was being used.

Currently on hold for more information on how to trigger a withdrawal when Fault Proof system is not enabled on alt-da.
Thank you!