pyth-crosschain/ethereum/README.md

# Pyth Ethereum Contract

This directory contains The Pyth contract on Ethereum and utilities to deploy it in EVM chains.

## Installation

Run the following command to install required dependencies for the contract:

```
# xc-governance-sdk-js is a local dependency that should be built
# it is used in deployment (truffle migrations) to generate/sanity check
# the governance VAAs 
pushd third_party/pyth/xc-governance-sdk-js && npm ci && popd
npm ci
```

## Deployment
Please refer to [Deploying.md](./Deploying.md) for more information.

## Foundry

Foundry can be installed by the official installer, or by running our helper script which will automatically pull the correct installation script individually for Foundry and the Solidity compiler for your current OS. This may work better if you are running into networking/firewall issues using Foundry's Solidity installer. To use helper script, run the command below from this directory:

``` sh
pyth-crosschain/ethereum $ bash ../scripts/install-foundry.sh
```

You need to install npm dependencies as described in [Installation](#installation). Also, you need to run the following
command to install forge dependencies:

```
npm run install-forge-deps
```

After installing the dependencies. Run `forge build` to build the contracts and `forge test` to
test the contracts using tests in `forge-test` directory.

### Gas Benchmark

You can use foundry to run benchmark tests written in [`forge-test/GasBenchmark.t.sol`](./forge-test/GasBenchmark.t.sol). To run the tests with gas report
you can run `forge test --gas-report --match-contract GasBenchmark`. However, as there are multiple benchmarks, this might not be useful. You can run a
specific benchmark test by passing the test name using `--match-test`. A full command to run `testBenchmarkUpdatePriceFeedsFresh` benchmark test is like this:

```
forge test --gas-report --match-contract GasBenchmark --match-test testBenchmarkUpdatePriceFeedsFresh
```

A gas report should have a couple of tables like this:

```
╭───────────────────────────────────────────────────────────────────────────────────────────┬─────────────────┬────────┬────────┬─────────┬─────────╮
│ node_modules/@openzeppelin/contracts/proxy/ERC1967/ERC1967Proxy.sol:ERC1967Proxy contract ┆                 ┆        ┆        ┆         ┆         │
╞═══════════════════════════════════════════════════════════════════════════════════════════╪═════════════════╪════════╪════════╪═════════╪═════════╡
│ Deployment Cost                                                                           ┆ Deployment Size ┆        ┆        ┆         ┆         │
├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤
│ 164236                                                                                    ┆ 2050            ┆        ┆        ┆         ┆         │
├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤
│ Function Name                                                                             ┆ min             ┆ avg    ┆ median ┆ max     ┆ # calls │
├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤
│ .............                                                                             ┆ .....           ┆ .....  ┆ .....  ┆ .....   ┆ ..      │
├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤
│ updatePriceFeeds                                                                          ┆ 383169          ┆ 724277 ┆ 187385 ┆ 1065385 ┆ 2       │
├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤
│ .............                                                                             ┆ .....           ┆ .....  ┆ .....  ┆ .....   ┆ ...     │
╰───────────────────────────────────────────────────────────────────────────────────────────┴─────────────────┴────────┴────────┴─────────┴─────────╯
```

For most of the methods, the minimum gas usage is an indication of our desired gas usage. Because the calls that store something in the storage
for the first time in `setUp` use significantly more gas. For example, in the above table, there are two calls to `updatePriceFeeds`. The first
call has happend in the `setUp` method and costed over a million gas and is not intended for our Benchmark. So our desired value is the
minimum value which is around 380k gas.

If you like to optimize the contract and measure the gas optimization you can get gas snapshots using `forge snapshot` and evaluate your
optimization with it. For more information, please refer to [Gas Snapshots documentation](https://book.getfoundry.sh/forge/gas-snapshots).
Once you optimized the code, please share the snapshot difference (generated using `forge snapshot --diff <old-snapshot>`) in the PR too.
This snapshot gas value also includes an initial transaction cost as well as reading from the contract storage itself. You can get the
most accurate result by looking at the gas report or the gas shown in the call trace with `-vvvv` argument to `forge test`.