Can ReentrancyGuard be used in Proxies?

Question

ReentrancyGuard's _status is set in the constructor & we can't set it anywhere else: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/64e48203cecad94f02de9891ecdeed4d629c6dae/contracts/security/ReentrancyGuard.sol#L39-L41.

And in the proxy contract we can't have a constructor, only the initialize(), can the ReentrancyGuard's nonReentrant modifier be used in a proxy contract?

Answer 1

Okay, we can use the ReentrancyGuardUpgradeable contract from import "@openzeppelin/contracts-upgradeable/security/ReentrancyGuardUpgradeable.sol";

Then simply call the __ReentrancyGuard_init() which set's the _status.

The modifier name remains nonReentrant(). This works for me!

Answer 2

Like @DiamondDust said, you can call __ReentrancyGuard_init()

But when you check the contract ReentrancyGuardUpgradeable, you'll see that the modifier nonReentrant() checks _status first.

require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

Even without initializing _status, the check can succeed.