Function: backstopLiquidate(address account, uint256 subaccount, uint256 leverage, Settlement settlement)

The positionTakeover function allows a liquidator to take over the entire position of the liquidatee that has become liquidatable.

Inputs

• account

  • Control: Full control.

  • Constraints: A valid address that own a position in the specified subaccount. The account must be eligible for liquidation.

  • Impact: Identifies which user’s subaccount will be liquidated.

• subaccount

  • Control: Full control.

  • Constraints: A valid subaccount of account — must contain active positions, which can be liquidated.

  • Impact: Determines the subaccount that will be liquidated.

• leverage

  • Control: Full control.

  • Constraints: Must be a valid leverage value.

  • Impact: new applied leverage.

• settlement

  • Control: Full control.

  • Constraints: Must be a valid settlement type.

  • Impact: Decides where the collateral goes.

Branches and code coverage

Intended branches

• marginDelta, gtlRpnl and liquidateeRpnl are calculated correctly.

  Test coverage

Negative behavior

• Reverts if position is not liquidatable.

  Negative test

• Reverts if position amount is zero.

  Negative test

• Invalid leverage.

  Negative test

• Caller is not a GTLOperator.

  Negative test

Function call analysis

• self.isLiquidatable({account: account, subaccount: subaccount, margin: self.collateralManager.getMarginAccountBalance(account, subaccount).toInt256() - liquidateeFundingPayment})

  • What is controllable? account, subaccount, and settlement.

  • If the return value is controllable, how is it used and how can it go wrong? If margin is less than zero, it returns true, even if totalPnL covers the debt.

  • What happens if it reverts, reenters or does other unusual control flow? There are not any problems here.