Compound Comet

Getting started

1. Clone the repo
2. Run yarn install

Env variables

The following env variables are used in the repo. One way to set up these env variables is to create a .env in the root directory of this repo.

Required env variables:

ETHERSCAN_KEY=<key>
INFURA_KEY=<key>

Optional env variables:

SNOWTRACE_KEY=<key>
COINMARKETCAP_API_KEY=<key>
REPORT_GAS=true
ETH_PK=<eth-key>             # takes precedence over MNEMONIC
MNEMONIC=<mnemonic>

Git hooks

The repo's Git hooks are defined the .githooks/ directory.

You can enable them by running:

# requires git version 2.9 or greater
git config core.hooksPath .githooks

You can skip pre-commit checks with the -n flag:

git commit -n -m "commit without running pre-commit hook"

Multi-chain support

Currently, Avalanche mainnet and testnet (fuji) are supported. This means that deployment scripts, scenarios, and spider all work for Avalanche.

To use this project with other chains, the block explorer API key for your target chain must be set in .env (e.g. SNOWTRACE_KEY for Avalanche).

An example deployment command looks like:

yarn hardhat deploy --network fuji --deployment usdc

Comet protocol contracts

Comet.sol - Contract that inherits CometMainInterface.sol and is the implementation for most of Comet's core functionalities. A small set of functions that do not fit within this contract are implemented in CometExt.sol instead, which Comet DELEGATECALLs to for unrecognized function signatures.

CometExt.sol - Contract that inherits CometExtInterface.sol and is the implementation for extra functions that do not fit within Comet.sol, such as approve.

CometInterface.sol - Abstract contract that inherits CometMainInterface.sol and CometExtInterface.sol. This interface contains all the functions and events for Comet.sol and CometExt.sol and is ERC-20 compatible.

CometMainInterface.sol - Abstract contract that inherits CometCore.sol and contains all the functions and events for Comet.sol.

CometExtInterface.sol - Abstract contract that inherits CometCore.sol and contains all the functions and events for CometExt.sol.

CometCore.sol - Abstract contract that inherits CometStorage.sol, CometConfiguration.sol, and CometMath.sol. This contracts contains functions and constants that are shared between Comet.sol and CometExt.sol.

CometStorage.sol - Contract that defines the storage variables used for the Comet protocol.

CometConfiguration.sol - Contract that defines the configuration structs passed into the constructors for Comet.sol and CometExt.sol.

CometMath.sol - Contract that defines math functions that are used throughout the Comet codebase.

CometFactory.sol - Contract that inherits CometConfiguration.sol and is used to deploy new versions of Comet.sol. This contract will mainly be called by the Configurator during the governance upgrade process.

Configurator contracts

Configurator.sol - Contract that inherits ConfiguratorStorage.sol. This contract manages Comet's configurations and deploys new implementations of Comet.

ConfiguratorStorage.sol - Contract that inherits CometConfiguration.sol and defines the storage variables for Configurator.sol.

Supplementary contracts

Bulker.sol - Contract that allows multiple Comet functions to be called in a single transaction.

CometRewards.sol - Contract that allows Comet users to claim rewards based on their protocol participation.

Vendor contracts

Third-party contracts (e.g. OZ proxies) live under contracts/vendor.

There are currently two Comet-related contracts that extend directly from the vendor contracts. The contracts are:

ConfiguratorProxy.sol - This contract inherits OZ's TransparentUpgradeableProxy.sol. We override the _beforeFallback function so that the proxy's admin can directly call the implementation. We only need this feature for the Configurator's proxy.

CometProxyAdmin.sol - This contract inherits OZ's ProxyAdmin.sol. We created a new function called deployAndUpgradeTo, which calls Configurator.deploy(0xCometProxy) and upgrades Comet proxy's implementation to this newly deployed Comet contract. This function is needed so we can pass the address of the new Comet to the Proxy.upgrade() call in one transaction.

Usage

Look at the scripts section inside package.json to find all commands.

Build contracts

Compiles contracts.

yarn build

Lint contracts

Contract linting is done via Solhint.

yarn lint-contracts
yarn lint-contracts:fix // will attempt to automatically fix errors

Solhint configuration is saved in .solhint.json.

Run tests

Runs all tests in the test directory.

yarn test

Run tests with coverage tool

Runs all tests while also evaluating code coverage.

yarn test:coverage

The coverage report will be saved in the coverage directory.

Run tests with gas profiler

Set up the following env variables:

• REPORT_GAS=true
• COINMARKETCAP_API_KEY=your_coinmarket_api_key optional, only if you want to see cost in USD

Run forge tests

Experimental support for foundry has been added, so assuming forge is installed:

forge test

See the GitHub workflow for an example.

Deploy contracts

Deploys contracts to a specified chain using a deployment script.

yarn hardhat deploy --network mainnet --deployment usdc

Spider

Spider is a tool for programmatically fetching all protocol-related contracts from a desired network. Contracts are pulled in starting from the root set of contracts defined in roots.json. Then, it discovers and pulls in the web of related contracts (relations defined in relations.json), recursively iterating over new contracts until there are no more contracts left to discover. With spider, we can generate the comprehensive list of relevant contracts for each deployment directly from the blockchain without having to manually maintain all the addresses.

Once run locally, the spider task will generate a list of all the relevant contracts for a specific deployment in a file called aliases.json.

Note: Spider relies on the Etherscan API to pull in contract-related info such as ABIs.

Run spider task

Note: Make sure $ETHERSCAN_KEY is set as an env variable.

npx hardhat spider --network mainnet --deployment usdc

Delete spider artifacts

You can delete all spider artifacts using the --clean flag:

npx hardhat spider --clean

Spider configs

The spider script uses configuration from two files to start its crawl:

• roots.json
• relations.json

Both these contracts are committed to the repo under deployments/<network>/<deployment>/<file>.json. The roots.json config contains the address of the root contract for spider to start crawling from. The relations.json config defines all the different relationships and rules that spider will follow when crawling. The following section will go over in detail the set of rules defined in relations.json.

Defining relations

Currently, these are the 3 types of rules in relations.json that can be defined for a contract:

1. Alias - A rule to derive the key that is assigned to this contract in pointers.json. If this rule is not provided, the contract name will be used as the alias instead. This rule has two special characters: @ and +. @ followed by a function name is used to read a value from that contract's function. + is used as a delimiter. Example: @symbol+Delegator will equate to cDaiDelegator for cDai's delegator contract.
2. Relations - The names of the contract's functions to call to fetch dependent contracts.
3. Implementation - The name of the contract's function to call to grab its implementation address. This should only be defined for proxy contracts.

Scenarios

Scenarios are high-level property and ad-hoc tests for the Comet protocol. To run and check scenarios:

npx hardhat scenario

For more information, see SCENARIO.md.

Migrations

Migrations are used to make proposals to governance, for changes to the live protocol. A migration script has two parts: prepare and enact. The prepare step can perform necessary preparation of artifacts for the enact step, which is where the proposal gets made.

Migrations integrate with scenarios, so that changes are automatically tested against the entire scenario suite, with and without the proposal. In fact, all combination