SyncRedeemQueue

Overview

The SyncRedeemQueue contract enables synchronous (instant) redemptions of vault shares. Unlike RedeemQueue, where requests are batched and settled after an oracle report and liquidity handling, shares are burned and assets paid out in the same transaction at the latest oracle price. Instant exits are constrained by a price penalty, available vault liquidity, and a leaky-bucket daily limit.

Roles and Permissions

Role	Permission
SET_SYNC_REDEEM_PARAMS_ROLE	Updates the synchronous redemption penalty, maximum report age, and daily limit

The role is checked against the vault's ACL.

Configuration and State

Parameters

function syncRedeemParams()
    external
    view
    returns (uint256 penaltyD6, uint32 maxAge, uint256 usage, uint256 dailyLimit, uint256 latestRequestTimestamp)

Parameter	Description	Update rule or constraint
penaltyD6	Penalty applied to synchronous redemptions, in D6 precision (1e4 = 1%)	At most 5e5 (50%)
maxAge	Maximum allowed age of the oracle report used for pricing, in seconds	Non-zero, at most 365 days
usage	Stored leaky-bucket usage before decay since the last synchronization	Updated when a redemption or parameter change synchronizes usage
dailyLimit	Leaky-bucket capacity for synchronous redemptions, denominated in shares	Divisible by 86400
latestRequestTimestamp	Timestamp of the latest usage synchronization	Updated together with usage

The configurable parameters are set during initialization and updated via setSyncRedeemParams(penaltyD6, maxAge, dailyLimit).

Behavior

Redeem Flow

A user calls redeem(shares, receiver). The queue then completes the following steps in one transaction:

1. Rejects the call if the queue is paused by the vault.

2. Reads the latest oracle report for the queue's asset and validates it:

   • the report must not be flagged as suspicious and must have a non-zero price;
   • the report must be fresh: report.timestamp + maxAge >= block.timestamp, otherwise the call reverts with StaleReport().

3. Applies the penalty and the redeem fee to the share amount:

   sharesToRedeem = shares * (1e6 - penaltyD6) / 1e6;
   feeShares = feeManager.calculateRedeemFee(sharesToRedeem);
   assets = (sharesToRedeem - feeShares) * 1e18 / priceD18;

4. Reverts with InsufficientAssets(uint256 requested, uint256 available) if the vault's liquid assets do not cover the payout.

5. Reverts with DailyLimitOverflow() if the full shares amount exceeds the remaining daily limit; otherwise adds it to the current usage.

6. Burns shares from the caller, mints feeShares to the fee recipient, triggers the vault's redeem hook, and transfers the assets to receiver.

7. Updates the RiskManager vault balance.

Daily Limit (Leaky Bucket)

The queue throttles instant exits with a leaky-bucket counter denominated in shares:

• Every redemption adds its share amount to usage.
• usage decays linearly over time at a rate of dailyLimit / 24 hours.
• A redemption reverts if shares > dailyLimit - usage at execution time.

Because capacity refills continuously, dailyLimit is not a strict rolling 24-hour cap: up to 2 * dailyLimit shares can be redeemed within some 24-hour windows (dailyLimit from initially available capacity plus dailyLimit from refill). Risk limits should account for this burst behavior.

dailyLimit must be divisible by 24 hours (86400) so the linear decay is exact; otherwise setSyncRedeemParams reverts with InvalidDailyLimit().

Functions

View Functions

Function	Description
name()	Returns "SyncRedeemQueue"
syncRedeemParams()	Returns the configured parameters and stored usage state
remainingDailyLimit()	Returns usage after linear decay and the currently available redemption capacity
getLiquidAssets()	Returns liquidity reported by the vault for this queue
canBeRemoved()	Returns true because the queue keeps no pending requests

getLiquidAssets() delegates to vault.getLiquidAssets(). If no redeem hook is configured, the vault returns its direct asset balance; otherwise it returns the hook's liquidity estimate.

State-Changing Functions

Function	Access	Description
setSyncRedeemParams(penaltyD6, maxAge, dailyLimit)	SET_SYNC_REDEEM_PARAMS_ROLE in the vault ACL	Synchronizes usage, then updates the pricing and limit parameters
redeem(shares, receiver)	Public	Burns shares and transfers assets immediately after all checks pass

Events

• Redeemed(address indexed account, uint256 shares, uint256 assets, uint256 feeShares): Emitted on a successful synchronous redemption.
• SyncRedeemParamsSet(uint256 penaltyD6, uint32 maxAge, uint256 dailyLimit): Emitted when queue parameters are updated.

Errors

Error	Reason
ZeroValue()	Zero shares, zero receiver, the payout rounds to zero, or maxAge == 0 in the setter
QueuePaused()	Redemptions disabled via vault pause mechanism
InvalidReport()	Latest oracle report is suspicious or zero-priced
StaleReport()	Latest oracle report is older than maxAge
InsufficientAssets(uint256 requested, uint256 available)	Vault lacks liquid assets to cover the payout
DailyLimitOverflow()	Redemption exceeds the remaining daily limit
InvalidDailyLimit()	dailyLimit is not divisible by 86400
Forbidden()	Caller lacks SET_SYNC_REDEEM_PARAMS_ROLE
TooLarge()	Parameter exceeds the allowed maximum

Invariants and Limitations

Key Invariants

1. Instant Execution: shares are burned and assets paid out in the redeem transaction; no pending requests exist.
2. Fresh Pricing: redemptions revert if the latest oracle report is older than maxAge or flagged as suspicious.
3. Liquidity-Bounded: without a redeem hook, available liquidity is the vault's direct asset balance. With a hook, liquidity is determined by that hook and may include assets available from eligible subvaults (for example, BasicRedeemHook counts both).
4. Rate-Limited: total instant redemptions are throttled by the leaky-bucket daily limit.

Source

SyncRedeemQueue.sol at 69bbaf1