Upgradeable smart contracts - Remix Tutorial 18

Key Concepts:

• Proxy Smart Contracts
• UUPS (Universal Upgradeable Proxy Standard)
• Remix IDE
• Upgradable ERC20 Token
• Proxy Contract
• Implementation Contract
• Initialization Function
• Contract Upgrade
• Contract Verification

1. Introduction to Proxy Smart Contracts and UUPS

• The video introduces the concept of proxy smart contracts, highlighting their use for upgradability.
• It specifically focuses on the UUPS (Universal Upgradeable Proxy Standard) as a popular standard for proxy contracts.
• The demonstration is conducted within the Remix IDE, a widely used platform for smart contract development.

2. Setting up the UUPS Template in Remix

• The video demonstrates how to create a new project using a UUPS template within Remix.
• Step 1: Navigate to the file explorer's hamburger menu.
• Step 2: Select "Create using template."
• Step 3: Search for "UUPS templates."
• Step 4: Choose the "Upgradable ERC20 token" template.
• This template provides the initial code for an upgradable token contract.

3. Deploying the Initial Contract with a Proxy

• The video explains the deployment process, emphasizing the options provided by Remix for upgradable contracts.
• Remix automatically detects the upgradable nature of the contract and offers extra deployment options.
• Step 1: Go to the "Deploy" tab in Remix.
• Step 2: Select the "Deploy with proxy" checkbox.
• Step 3: Provide the argument for the initialized function (this function sets up the initial state of the contract).
• Step 4: Click "Deploy" and approve the two resulting transactions.
• The deployment involves two transactions: one for the token contract and one for the proxy contract.
• The video notes that while the Remix VM provides near-instantaneous transactions, deployments on public blockchains require waiting for each transaction to be mined before proceeding.

4. Interacting with the Token via the Proxy

• The video demonstrates how to interact with the deployed token contract through the proxy contract.
• It emphasizes that you must use the interface of the proxy to interact with the token's functions.
• Example: Reading the name of the token using the proxy's interface.

5. Upgrading the Contract Implementation

• The core of the video focuses on the upgrade process, showcasing how to deploy a new implementation and update the proxy.
• Step 1: Create a new file in the file explorer for the new implementation contract.
• Step 2: Implement the new logic in the new contract (in this case, a version function is added).
• Step 3: In the "Deploy" tab, clear the deployed contracts (this is a UI-level action and doesn't affect the blockchain state).
• Step 4: Select the "Upgrade with proxy" option.
• Step 5: Input the address of the existing proxy contract.
• Step 6: Click "Deploy" and approve the two resulting transactions.
• The upgrade process involves deploying the new token implementation and then updating the proxy contract to point to the new implementation's address.

6. Verifying the Upgrade and New Functionality

• The video demonstrates how to verify that the upgrade was successful and that the new functionality is accessible.
• After the upgrade, the new token contract is visible in the "Deployed Contracts" section.
• The new version function is available and returns the expected output.

7. Contract Verification (Side Note)

• The video briefly mentions the importance of verifying proxy smart contracts using the verification plugin.
• It refers viewers to another video for detailed instructions on contract verification.

8. Conclusion

• The video concludes by summarizing the process of using upgradable smart contracts in Remix.
• It highlights the use of UUPS and the steps involved in deploying, interacting with, and upgrading proxy contracts.