foundry-toolchain Action

This GitHub Action installs Foundry, the blazing fast, portable and modular toolkit for Ethereum application development.

Example workflow

name: CI

permissions: {}

on:
  push:
  pull_request:
  workflow_dispatch:

env:
  FOUNDRY_PROFILE: ci

jobs:
  check:
    name: Foundry project
    runs-on: ubuntu-latest
    permissions:
      contents: read
    steps:
      - uses: actions/checkout@v6
        with:
          persist-credentials: false
          submodules: recursive

      - name: Install Foundry
        uses: foundry-rs/foundry-toolchain@v1

      - name: Show Forge version
        run: forge --version

      - name: Run Forge fmt
        run: forge fmt --check

      - name: Run Forge build
        run: forge build --sizes

      - name: Run Forge tests
        run: forge test -vvv

Inputs

Name	Required	Default	Description	Type
version	No	stable	Version to install, e.g. stable, nightly or any SemVer version with or without v prefix (e.g. v1.5.0 or 1.5.0)	string
cache	No	true	Whether to cache Foundry data or not.	bool
cache-key	No	${{ github.job }}-${{ github.ref }}-${{ github.sha }}	The cache key to use for caching.	string
cache-restore-keys	No	See Caching	The cache keys to use for restoring the cache.	string[]

Caching

By default, this action matches Forge's behavior and caches all RPC responses, Etherscan queries, and other data in the ~/.foundry/cache directory. This is done to speed up the tests and avoid hitting the rate limit of your RPC provider.

By default, the cache is restored from the first of these restore keys that matches:

1. ${{ github.job }}-${{ github.ref }}-: the latest cache for the current ref (a branch, a tag, or a PR merge ref such as refs/pull/123/merge).
2. ${{ github.job }}-refs/heads/${{ github.base_ref }}-: on pull requests only, the latest cache for the base branch, so the first run of a PR starts warm.
3. ${{ github.job }}-: the legacy job-wide prefix, kept so caches created before ref scoping remain usable. It can match caches from unrelated refs, which is why it is tried last.

A new cache is then saved under ${{ github.job }}-${{ github.ref }}-${{ github.sha }}:

• The cache is saved even when the job fails, so RPC responses fetched by a failing fork test are not lost.
• When there are no changes to the fork tests, the cache does not change but the key does, since the key is based on the commit hash.
• When the fork tests are changed, both the cache and the key are updated.
• Cache keys are immutable, so re-running a job for the same commit restores the cache saved by the first attempt and does not save a new one.

To share caches across refs on purpose, set cache-restore-keys yourself (see Custom Cache Keys).

If you would like to disable the caching (e.g. because you want to implement your own caching mechanism), you can set the cache input to false, like this:

- name: Install Foundry
  uses: foundry-rs/foundry-toolchain@v1
  with:
    cache: false

Custom Cache Keys

You have the ability to define custom cache keys by utilizing the cache-key and cache-restore-keys inputs. This feature is particularly beneficial when you aim to tailor the cache-sharing strategy across multiple jobs. It is important to ensure that the cache-key is unique for each execution to prevent conflicts and guarantee successful cache saving.

For instance, if you wish to utilize a shared cache between two distinct jobs, the following configuration can be applied:

- name: Install Foundry
  uses: foundry-rs/foundry-toolchain@v1
  with:
    cache-key: custom-seed-test-${{ github.sha }}
    cache-restore-keys: |-
      custom-seed-test-
      custom-seed-
---
- name: Install Foundry
  uses: foundry-rs/foundry-toolchain@v1
  with:
    cache-key: custom-seed-coverage-${{ github.sha }}
    cache-restore-keys: |-
      custom-seed-coverage-
      custom-seed-

Deleting Caches

You can delete caches via the GitHub Actions user interface. Just go to your repo's "Actions" page:

https://github.com/<OWNER>/<REPO>/actions/caches

Then, locate the "Management" section, and click on "Caches". You will see a list of all of your current caches, which you can delete by clicking on the trash icon.

For more detail on how to delete caches, read GitHub's docs on managing caches.

Fuzzing

Note that if you are fuzzing in your fork tests, the cache strategy above will not work unless you set a fuzz seed. You might also want to reduce your number of RPC calls by using Multicall.

Summaries

You can add the output of Forge and Cast commands to GitHub step summaries. The summaries support GitHub flavored Markdown.

For example, to add the output of forge snapshot to a summary, you would change the snapshot step to:

- name: Run snapshot
  run: NO_COLOR=1 forge snapshot >> $GITHUB_STEP_SUMMARY

See the official GitHub docs for more information.

Building

When opening a PR, you must build the action exactly following the below steps for CI to pass:

Install nvm and pnpm.

$ nvm install
$ nvm use
$ pnpm install --frozen-lockfile
$ pnpm run typecheck
$ pnpm run build

You must use the Node.js version 24.13.0 to build.