ScopeLift Foundry Template

An opinionated template for Foundry projects.

Please read the full README before using this template.

• Usage
• Overview
  • foundry.toml
  • CI
  • Test Structure
• Configuration
  • Coverage
  • Slither
  • GitHub Code Scanning

Usage

To use this template, use one of the below approaches:

1. Run forge init --template ScopeLift/foundry-template in an empty directory.
2. Click here to generate a new repository from this template.
3. Click the "Use this template" button from this repo's home page.

It's also recommend to install scopelint, which is used in CI. You can run this locally with scopelint fmt and scopelint check. Note that these are supersets of forge fmt and forge fmt --check, so you do not need to run those forge commands when using scopelint.

Overview

This template is designed to be a simple but powerful configuration for Foundry projects, that aims to help you follow Solidity and Foundry best practices Writing secure contracts is hard, so it ships with strict defaults that you can loosen as needed.

foundry.toml

The foundry.toml config file comes with:

• A fmt configuration.
• default, lite, and ci profiles.

Both of these can of course be modified. The default and ci profiles use the same solc build settings, which are intended to be the production settings, but the ci profile is configured to run deeper fuzz and invariant tests. The lite profile turns the optimizer off, which is useful for speeding up compilation times during development.

It's recommended to keep the solidity configuration of the default and ci profiles in sync, to avoid accidentally deploying contracts with suboptimal configuration settings when running forge script. This means you can change the solc settings in the default profile and the lite profile, but never for the ci profile.

Note that the foundry.toml file is formatted using Taplo via scopelint fmt.

CI

Robust CI is also included, with a GitHub Actions workflow that does the following:

• Runs tests with the ci profile.
• Verifies contracts are within the size limit of 24576 bytes.
• Runs forge coverage and verifies a minimum coverage threshold is met.
• Runs slither, integrated with GitHub's code scanning. See the Configuration section to learn more.

The CI also runs scopelint to verify formatting and best practices:

• Checks that Solidity and TOML files have been formatted.
  • Solidity checks use the foundry.toml config.
  • Currently the TOML formatting cannot be customized.
• Validates test names follow a convention of test(Fork)?(Fuzz)?_(Revert(If_|When_){1})?\w{1,}. ¹
• Validates constants and immutables are in ALL_CAPS.
• Validates internal functions in src/ start with a leading underscore.
• Validates function names and visibility in forge scripts to 1 public run method per script. ²

Note that the foundry-toolchain GitHub Action will cache RPC responses in CI by default, and it will also update the cache when you update your fork tests.

Test Structure

The test structure is configured to follow recommended best practices. It's strongly recommended to read that document, as it covers a range of aspects. Consequently, the test structure is as follows:

• The core protocol deploy script is script/Deploy.sol. This deploys the contracts and saves their addresses to storage variables.
• The tests inherit from this deploy script and execute Deploy.run() in their setUp method. This has the effect of running all tests against your deploy script, giving confidence that your deploy script is correct.
• Each test contract serves as describe block to unit test a function, e.g. contract Increment to test the increment function.

Configuration

After creating a new repository from this template, make sure to set any desired branch protections on your repo.

Coverage

The ci.yml has coverage configured by default, and contains comments explaining how to modify the configuration. It uses: The [lcov] CLI tool to filter out the test/ and script/ folders from the coverage report.

• The romeovs/lcov-reporter-action action to post a detailed coverage report to the PR. Subsequent commits on the same branch will automatically delete stale coverage comments and post new ones.
• The zgosalvez/github-actions-report-lcov action to fail coverage if a minimum coverage threshold is not met.

Be aware of foundry's current coverage limitations:

• You cannot filter files/folders from forge directly, so lcov is used to do this.
• forge coverage always runs with the optimizer off and without via-ir, so if you need either of these to compile you will not be able to run coverage.

Remember not to optimize for coverage, but to optimize for well thought-out tests.

Slither

In ci.yml, you'll notice Slither is configured as follows:

slither-args: --filter-paths "./lib|./test" --exclude naming-convention,solc-version

This means Slither is not run on the lib or test folders, and the naming-convention and solc-version checks are disabled.

This slither-args field is where you can change the Slither configuration for your project, and the defaults above can of course be changed.

Notice that Slither will run against script/ by default. Carefully written and tested scripts are key to ensuring complex deployment and scripting pipelines execute as planned, but you are free to disable Slither checks on the scripts folder if it feels like overkill for your use case.

For more information on configuration Slither, see the documentation. For more information on configuring the slither action, see the slither-action repo.

GitHub Code Scanning

As mentioned, the Slither CI step is integrated with GitHub's code scanning feature. This means when your jobs execute, you'll see two related checks:

1. CI / slither-analyze
2. Code scanning results / Slither

The first check is the actual Slither analysis. You'll notice in the ci.yml file that this check has a configuration of fail-on: none. This means this step will never fail CI, no matter how many findings there are or what their severity is. Instead, this check outputs the findings to a SARIF file³ to be used in the next check.

The second check is the GitHub code scanning check. The slither-analyze job uploads the SARIF report to GitHub, which is then analyzed by GitHub's code scanning feature in this step. This is the check that will fail CI if there are Slither findings.

By default when you create a repository, only alerts with the severity level of Error will cause a pull request check failure, and checks will succeed with alerts of lower severities. However, you can configure which level of slither results cause PR check failures.

It's recommended to conservatively set the failure level to Any to start, and to reduce the failure level if you are unable to sufficiently tune Slither or find it to be too noisy.

Findings are shown directly on the PR, as well as in your repo's "Security" tab, under the "Code scanning" section. Alerts that are dismissed are remembered by GitHub, and will not be shown again on future PRs.

Note that code scanning integration only works for public repos, or private repos with GitHub Enterprise Cloud and a license for GitHub Advanced Security. If you have a private repo and don't want to purchase a license, the best option is probably to:

• Remove the Upload SARIF file step from CI.
• Change the Run Slither step to fail-on whichever level you like, and remove the sarif output.
• Use triage mode locally and commit the resulting slither.db.json file, and make sure CI has access to that file.

Footnotes

1. A rigorous test naming convention is important for ensuring that tests are easy to understand and maintain, while also making filtering much easier. For example, one benefit is filtering out all reverting tests when generating gas reports. ↩

2. Limiting scripts to a single public method makes it easier to understand a script's purpose, and facilitates composability of simple, atomic scripts. ↩

3. SARIF (Static Analysis Results Interchange Format) is an industry standard for static analysis results. You can read learn more about SARIF here and read about GitHub's SARIF support here. ↩