# GC withdrawal contract ## Background From [Spec Gnosis Chain withdrawals #1](https://github.com/gnosischain/specs/pull/1) - During block processing, state transition must call `WITHDRAWAL_CONTRACT` function ```solidity function withdrawals(uint64[] amounts, address[] addresses) ``` - If transaction reverts, the block is invalid. So if a specific state (i.e. not enough funds) causes a revert in all cases, the network halts ## Deposit flow 1. Bridge GNO from mainnet to Gnosis Chain 2. Swap GNO for mGNO 3. Deposit mGNO to deposit contract Contract deployments - GBC deposit contract on xDai Mainnet ([ref](https://github.com/gnosischain/configs/blob/3a571e1c3e753757ccbde13fdbef51eb6930ba23/mainnet/config.yaml#L59)): [`0x0B98057eA310F4d31F2a452B414647007d1645d9`](https://gnosisscan.io/address/0x0b98057ea310f4d31f2a452b414647007d1645d9). Contract source at: [gnosischain/deposit-contract](https://github.com/gnosischain/deposit-contract/blob/c7217fccac3049901f78547f4024127fa1dcdcd4/contracts/SBCDepositContract.sol#L52) - mGNO contract on Gnosis [`0x722fc4DAABFEaff81b97894fC623f91814a1BF68`](https://gnosisscan.io/address/0x722fc4DAABFEaff81b97894fC623f91814a1BF68) - SBC wrapper proxy mGNO [`0x647507A70Ff598F386CB96ae5046486389368C66`](https://blockscout.com/xdai/mainnet/address/0x647507A70Ff598F386CB96ae5046486389368C66/contracts#address-tabs) - GNO token on xDAI [`0x9C58BAcC331c9aa871AFD802DB6379a98e80CEdb`](https://blockscout.com/xdai/mainnet/token/0x9C58BAcC331c9aa871AFD802DB6379a98e80CEdb/token-transfers) ## Withdrawal flow If the system transaction reverts due to lack of funds the chain halts. If the system is temporarily insolvent, which transaction should revert and when? To ensure the contract never reverts: - Allow the contract to mint some token, so it never runs out of funds - Queue the withdrawal action for latter processing with chosen mechanism - Add indirection, require the user to claim funds with a transaction that can safely revert - (unsafe) always pre-fund with maximum possible withdrawn value. This in potentially impossible since the deposit flow is unbounded given long enough timescales ### Flow A: auto-transfer + queue - System transaction: - Execution client calls withdrawal contract - Withdrawal contract calls checks for mGNO solvency: - If solvent: - Clear max of X pending withdrawals from queued state, then - `transfer` on mGNO contract to target address, or - (optional) withdrawal contract unwraps mGNO to GNO and transfers GNO to target address - If insolvent: - Add block's withdrawals to pending withdrawals contract state Withdrawal contract must be pre-funded but lack of funds do not halt the chain. After a period of insolvency, queue is cleared automatically during block processing. No input is required by users in any case. ### Flow B: user initiated claim - System transaction: - Execution client calls withdrawal contract - Withdrawal contract adds allowance to target address for withdrawal amount - User transaction - User calls `claim` on withdrawal contract - (optional) withdrawal contract unwraps mGNO to GNO and transfers to user If the system is not properly funded the second transaction will revert, but the chain will not halt. Requires an action on the user to obtain the funds. Allows the user to choose to claim mGNO or GNO. ### Flow C: mGNO mint - System transaction: - Execution client calls withdrawal contract - Withdrawal contract mints mGNO to target address - 2.1. User unwraps mGNO to GNO (reverts if wrapper contract insolvent) ## Source of funds _Numbers from Jan 26 2023_ - SBC wrapper proxy mGNO: holds wrapped GNO (145,337 GNO ~ 15,382,523 USD) - Deposit contract: holds staked mGNO (3,646,880 mGNO ~ 113,965 GNO). BTW: where is the rest of mGNO from the wrapper? - GNO on xDAI: current supply = 363,927.033 GNO ### Reward payout solvency estimation Withdrawal contract should have access to the deposit contract such that the principal of the stake is always available. Staking rewards must be supplied externally. This section estimates their upper bound: - Deposit inflows are technically unbounded in the Gnosis Chain. The practical upper bound is the entire supply of GNO. - TODO: APY estimation for Gnosis Beacon Chain # Withdrawal contract - System transaction that unwraps automatically to GNO - There should be an admin variable to switch to not unwrap - In the case the transfer fails, store withdrawable amount in a map. That value is claimable by the withdrawee, but can triggered by anyone - The WITHDRAWAL_CONTRACT = DEPOSIT_CONTRACT, to prevent need of allowances - WITHDRAWAL_CONTRACT may never became insolvent, as its a ponzi new deposit inflows pay for outflows, deposit contract balance may not - There must exist a way to topup the contract without triggering a deposit
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Increase `CHURN_LIMIT_QUOTIENT`

Rationale Current CHURN_LIMIT_QUOTIENT in Gnosis is low such that the network's validator set can change significantly in short periods of time posing unnecessary risks to the network. The original value was chosen without a great deal of care to facilitate staker onboarding UX. Even that argument will no longer apply with eip6110 (in-protocol deposits). CHURN_LIMIT_QUOTIENT dictates the validator_churn_limit which is constant through an epoch variable only to active validator count. def get_validator_churn_limit(state: BeaconState) -> uint64: """ Return the validator churn limit for the current epoch. """ active_validator_indices = get_active_validator_indices(state, get_current_epoch(state))

4/19/2023
How to run Hive with Lodestar

Get repo and build it (requires Go lang) git clone https://github.com/ethereum/hive go build . Checkout branch depending on current progress. For capella Mario's working on eth2-withdrawals-interop. Check with Mario Vega on current branch if working on new forks. master should reflect configurations that are somewhat stable. To run a test do: ./hive --client go-ethereum,lodestar-bn,lodestar-vc --sim eth2/withdrawals --sim.limit "/test-capella-fork" --sim.loglevel 5 client: flag sets which combo to run. For the example above, if you don't provide EL, CL and VC the test breaks: client go-ethereum,lodestar-bn,lodestar-vc. To test an interaction between Lodestar and Teku, do: client go-ethereum,lodestar-bn,lodestar-vc,teku-bn,teku-vc.

1/23/2023
Blobs booby-trap :bomb:

Given the conditions: To ensure an upper-bounded disk size, consensus clients must only store blobs within the MIN_EPOCHS_FOR_BLOBS_SIDECARS_REQUESTS time range Blobs from finalized blocks are considered available If the latest finalized checkpoint is before MIN_EPOCHS_FOR_BLOBS_SIDECARS_REQUESTS, there exist a range of blocks which cannot be checked for is_data_available. More context on ethereum/consensus-specs/pull/3141 Range sync When performing a range sync the client cannot know the latest finalized checkpoint until it syncs to the head. There are two possible scenarios:

1/23/2023
Gnosis merge client releases

Releases EL client Client Merge ready release Status Nethermind v1.14.6 ✅ Available https://github.com/NethermindEth/nethermind/releases/tag/1.14.6

11/24/2022
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