Upgradeable Proxy

An Upgradeable Proxy is designed to allow changing the logic of a contract after it has been deployed, while keeping the same address and state.

Key Idea

• Suppose you deploy a Wallet contract.

• Later, you discover a bug or want to add a new feature (e.g., a new function fun()).

• Normally, you'd have to deploy a new contract with the updated logic.

  But this would give a new contract address, which is a problem because:

  • Users or DApps interacting with the old address would break.
  • All old state data would be lost.

Solution:

• Use a Proxy Contract that holds:
  • The storage (state).
  • A pointer (address) to the Implementation Contract (logic).
• When you call the proxy, it delegates the call to the logic contract using DELEGATECALL.
• If you need to upgrade, you simply deploy a new Implementation Contract and point the proxy to it.
• The address of the proxy remains the same, so all users still interact with the same contract address.

Why Upgradeable Proxy?

• Upgradability: You can fix bugs or add features without changing the contract address.
• Persistent State: The proxy’s state remains intact across upgrades.
• Use Case: DeFi protocols, DAOs, and complex contracts that need continuous improvements.