This repo provides template code to complete Polymer Testnet Challenge 3: https://forum.polymerlabs.org/t/challenge-3-cross-contract-query-with-polymer/475

There's some basic information here in the README but a more comprehensive documentation can be found in the official Polymer documentation.

The repo is compatible with both Hardhat and Foundry development environments.

• Have git installed
• Have node installed (v18+)
• Have Foundry installed (Hardhat will be installed when running npm install)
• Have just installed (recommended but not strictly necessary)

You'll need some API keys from third party's:

• Optimism Sepolia and Base Sepolia Blockscout Explorer API keys
• Have an Alchemy API key for OP and Base Sepolia

Some basic knowledge of all of these tools is also required, although the details are abstracted away for basic usage.

To compile your contracts and start testing, make sure that you have all dependencies installed.

From the root directory run:

just install

to install the vIBC core smart contracts as a dependency.

Additionally Hardhat will be installed as a dev dependency with some useful plugins. Check package.json for an exhaustive list.

Note: In case you're experiencing issues with dependencies using the just install recipe, check that all prerequisites are correctly installed. If issues persist with forge, try to do the individual dependency installations...

Convert the .env.example file into an .env file. This will ignore the file for future git commits as well as expose the environment variables. Add your private keys and update the other values if you want to customize (advanced usage feature).

cp .env.example .env

This will enable you to sign transactions with your private key(s). If not added, the scripts from the justfile will fail.

The configuration file is where all important data is stored for the just commands and automation. We strive to make direct interaction with the config file as little as possible.

By default the configuration file is stored at root as config.json.

The configuration file is pre-set with the contract you will need to interact with on Base. Do not change it in order to correctly complete the challenge

The account associated with your private key must have both Base Sepolia and Optimism Sepolia ETH. To obtain the testnet ETH visit:

• Optimism Sepolia Faucet
• Base Sepolia Faucet

The project comes with an almost complete contract CCQueryUC.sol in the contracts directory. Your task is to implement two functions:

1. sendUniversalPacket - You will need to configure the payload to correctly be decoded and pass conditional logic of the base contract you are sending the packet to.
2. onUniversalAcknowledgement - You will need to emit the event LogAcknowledgment in order to provide evidence to complete this challenge.

Once you have completed the implementation of these two functions, run:

just run-challenge-3

This will:

1. Deploy your CCQueryUC.sol contract to Optimism
2. Send a packet to the Base Contract

Feel free to open an issue for questions, suggestions, or discussions related to this repository. For further discussion as well as a showcase of some community projects, check out the Polymer developer forum.

Thank you for being a part of our community!