SyncQueue

Overview

SyncQueue is the abstract base contract for synchronous queues: queues that settle a deposit or redemption in the same transaction the user sends. It is not deployable on its own. It is extended by:

SyncDepositQueue: instant deposits
SyncRedeemQueue: instant redemptions

Unlike Queue, a sync queue keeps no request history and does not wait for a future oracle report. It prices each action against the latest stored oracle report for its asset, which must be non-suspicious and no older than a configured maxAge. Unlike SignatureQueue, a sync queue needs no offchain signatures. Any eligible user can call it directly, and the vault’s deposit or redeem fee applies.

How sync queues compare

Property	Async (`DepositQueue` / `RedeemQueue`)	Signature queues	Sync queues
Settlement	After a later oracle report	Same transaction	Same transaction
Price source	Report submitted after the request	Signed order, checked against oracle	Latest stored report, within `maxAge`
Claim step	Yes	No	No
Offchain approval	No	Consensus signatures	No
Deposit/redeem fee	Applied	Not applied	Applied
Extra safeguards	`depositInterval` / `redeemInterval`	Nonce, deadline, signer quorum	`maxAge`, `penaltyD6`, daily limit (redeem only)

Storage

struct SyncQueueStorage {
    address vault;   // Vault (ShareModule) that owns this queue
    address asset;   // ERC20 token or native ETH handled by the queue
}

Storage lives in a custom slot derived with SlotLibrary.getSlot("SyncQueue", name_, version_).

Initialization

function __SyncQueue_init(address asset_, address vault_) internal

Called by child contracts from initialize
Reverts with ZeroValue if asset_ or vault_ is the zero address
Initializes the reentrancy guard

Creating a sync queue

Sync queues are deployed through the vault’s queue factories, like any other queue, with ShareModule.createQueue. The standard deployment registers queue implementations in this order:

Factory	Version `0`	Version `1`	Version `2`
`depositQueueFactory`	`DepositQueue`	`SignatureDepositQueue`	`SyncDepositQueue`
`redeemQueueFactory`	`RedeemQueue`	`SignatureRedeemQueue`	`SyncRedeemQueue`

Confirm the version on your network with factory.implementationAt(version) before you create a queue.

Interface compatibility

Sync queues are registered in ShareModule like any other queue, so they implement the methods the vault calls on every queue:

handleReport(priceD18, timestamp): no-op. Oracle reports do not change sync queue state.
canBeRemoved(): always true, because a sync queue holds no pending requests.
vault() and asset(): return the configured addresses.
name(): returns "SyncDepositQueue" or "SyncRedeemQueue".

Because canBeRemoved() is true, OracleHelper skips sync redeem queues when it subtracts outstanding redeem demand from vault TVL.

Errors

Error	Reason
`ZeroValue()`	Zero address at initialization, or a zero amount in a user action
`QueuePaused()`	The vault has paused this queue with `setQueueStatus`
`InvalidReport()`	The latest oracle report for the asset is suspicious or has price 0

Overview

Core Vaults

Lido Earn

stRATEGY Vault

USDG Yield Vault

Integrations

Resources

Overview

How sync queues compare

Storage

Initialization

Creating a sync queue

Interface compatibility

Errors

​Overview

​How sync queues compare

​Storage

​Initialization

​Creating a sync queue

​Interface compatibility

​Errors

Overview

How sync queues compare

Storage

Initialization

Creating a sync queue

Interface compatibility

Errors