Fallback Queued Liquidations

Technical Implementation Details

The liquidation process follows a tiered approach with three distinct phases:

1. Priority Phase (priorityDuration):

   1. Duration: Configurable (default 1 second)

   2. Only liquidators who previously called queueLiquidation() can execute liquidations

   3. Creates a short exclusive window for early liquidation detectors

   4. Prevents gas wars by giving priority to those who identified liquidation opportunities first

2. Regular Phase (regularDuration):

   1. Duration: Configurable (default 3 seconds)

   2. Any liquidator can execute liquidations regardless of whether they called queueLiquidation()

   3. Ensures liquidations proceed even if priority liquidators fail to execute

   4. Starts immediately after the priority phase ends

3. End Phase (endDuration):

   1. Duration: Configurable (default 30 seconds)

   2. Window during which liquidations can execute before the queue resets

   3. After this period, a new liquidation cycle with a new nonce must be initiated

   4. Prevents indefinite liquidation windows that could be exploited

Queue Management

The contract manages liquidation queues through several key mappings:

• regularQueue[bytes32 => LiqQueue]: Tracks liquidation windows for accounts/tokens

• priorityAccess[bytes32 => uint256]: Maps liquidator access rights to timestamps

• Queuing requires validation through canLiquidate() checks to prevent gaming the system

• Critical hash construction: keccak256(abi.encodePacked(account, liquidationTarget))

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User Interaction Functions

queueLiquidation()

Description: Queues a token-specific liquidation for an account, liquidating a specific pToken collateral by repaying active debt in the specified eToken. This function is called by the eToken itself to validate that liquidation is allowed based on the account's current liquidity.

Contract: Etoken

Function signature:

function queueLiquidation(
    address eToken,
    address pToken,
    address liquidator,
    address account
) external

Type	Name	Description
address	eToken	The earning token debt position to be repaid from the account
address	pToken	The position token to be liquidated from the account
address	liquidator	The account to execute the liquidation once queued
address	account	The account being liquidated and debt repaid on behalf of

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queueAccountLiquidation()

Description: Queues an account liquidation for an entire account, allowing a liquidator to repay a portion of the account's active debt. This function is called by the liquidator themselves to queue up a different account's liquidation.

Contract: MarketManager/MarketManagerIsolated

Function signature:

function queueAccountLiquidation(address account) external

Type	Name	Description
address	account	The account being liquidated and debt repaid on behalf of

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liquidateAccount()

Description: Liquidates an entire account by partially paying down debts, distributing all of the account's collateral, and recognizing remaining debt as bad debt. This function updates the account's EToken interest before solvency is checked and includes extensive run invariant checks to prevent potential asset callback exploits.

Contract: MarketManager/MarketManagerIsolated

Function signature:

function liquidateAccount(address account) external

Type	Name	Description
address	account	The address to liquidate completely

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liquidateExact()

Description: Liquidates a specific amount of borrowed assets from a borrower who has fallen below the collateral maintenance requirement. The liquidator repays a portion of the borrower's debt and receives a proportional amount of the borrower's collateral in return, plus a liquidation incentive.

Contract: Etoken

Function signature:

function liquidateExact(
    address account,
    uint256 amount,
    address pToken
) external returns (uint256)

Type	Name	Description
address	account	The account to be liquidated
uint256	amount	The exact amount of underlying asset to be repaid
address	pToken	The address of the pToken collateral to be seized

Return data:

Type	Description
uint256	The number of collateral tokens seized

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liquidate()

Description: Liquidates a borrower who has fallen below the collateral maintenance requirement. The liquidator repays a portion of the borrower's debt and receives a proportional amount of the borrower's collateral in return, plus a liquidation incentive. This function attempts to liquidate the maximum amount possible.

Contract: Etoken

Function signature:

function liquidate(
    address account,
    address pToken
) external returns (uint256)

Type	Name	Description
address	account	The account to be liquidated
address	pToken	The address of the pToken collateral to be seized

Return data:

Type	Description
uint256	The number of collateral tokens seized

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