AaveMigrator

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Overview

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Constructor parameters

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Requirements

• The AaveMigrator contract calls both subvaults through Subvault.call, so it must hold the verifier CALLER_ROLE on the vault.
• It always sends an ONCHAIN_COMPACT verification payload, so the calls below must be allowed with allowCalls in each subvault’s verifier. A Merkle-only permission is not enough.

• The target must already have borrowing capacity in Aave, because every step starts with a borrow from the target. In practice, the target needs some collateral supplied in advance.
• If the position relies on an Aave e-mode category, enable the same category on the target first. Otherwise its borrowing capacity and health factor are lower.

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Function: migrate

function migrate(uint256 maxUtilizationD18, uint256 percentageD6) external

1. Reverts with InvalidMaxUtilizationD18 or InvalidPercentageD6 if an argument is out of range, and with AlreadyMigrated if the migrator has finished or been killed.
2. Calls calculateSteps to get the number of steps, the debt and collateral per step and the expected remaining source debt.
3. Checks that both health factors are at or above their minimums and records each subvault’s equity.
4. Runs each step:
   1. The target borrows debtPerStep of the debt asset at variable rate.
   2. The target transfers it to the source.
   3. The source approves the pool and repays debtPerStep.
   4. The source withdraws collateralPerStep of collateral, sent straight to the target.
   5. The target approves the pool and supplies the collateral.
5. Checks both health factors again and adds up how much each subvault’s equity changed. Reverts with CumulativeErrorTooHigh if the total exceeds maxAllowedError.
6. Reverts with TooHighDeviation if the source’s remaining debt differs from the expected amount by more than maxAllowedError in value.
7. If the source’s remaining debt is worth maxAllowedError or less, marks the migration as finished and emits Migrated. Otherwise emits PartiallyMigrated, and the owner can call migrate again.

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Function: calculateSteps

function calculateSteps(uint256 maxUtilizationD18, uint256 percentageD6)
    external view
    returns (uint256 iterations, uint256 debtPerStep, uint256 collateralPerStep, uint256 expectedDebtAfter)

1. debtToMigrate is percentageD6 of the source’s variable debt. Reverts with InsufficientDebt if it is below minAllowedMigratingDebt.
2. Reverts with InvalidDebtAfterMigration if the leftover debt is worth more than maxAllowedError but is below minAllowedMigratingDebt. That would leave debt too large to ignore and too small to migrate later.
3. The largest step is the target’s available borrowing capacity times maxUtilizationD18, converted to the debt asset. It is also capped by the debt asset liquidity available in the Aave reserve.
4. iterations is debtToMigrate divided by the largest step, rounded up. Reverts with TooManyIterations if it exceeds MAX_ALLOWED_ITERATIONS (30) or no borrowing is possible.
5. debtPerStep is debtToMigrate / iterations, and collateralPerStep is collateral of the same value at oracle prices. Reverts with NotEnoughCollateral if the source does not hold enough collateral for all steps.

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Function: checkHFAndGetEquity

function checkHFAndGetEquity(address holder, uint256 minAllowedHealthFactorD18) external view returns (uint256)

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Function: kill

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Events

event Migrated(uint256 indexed timestamp, address indexed caller, uint256 indexed cumulativeError);
event PartiallyMigrated(uint256 indexed timestamp, address indexed caller, uint256 indexed cumulativeError, uint256 percentageD6);
event Killed(uint256 indexed timestamp, address indexed caller);

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Errors

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Notes

• Assets move between the subvaults through Aave, not through Vault.pushAssets or Vault.pullAssets. The RiskManager subvault balances are not updated by a migration.
• The vault’s total equity stays the same within maxAllowedError, so a migration should not change the vault’s reported value. Only the split between subvaults changes.