This Fourmolu Action helps to ensure that your Haskell project is formatted with Fourmolu. The action tries to find all Haskell source code files in your repository and fails if any of them are not formatted. In case of failure it prints the diff between the actual contents of the file and its formatted version.
In the simple case all you need to do is to add this step to your job:
- uses: fourmolu/fourmolu-action@v1
The @v1
after fourmolu-action
should be replaced with the version of the
Fourmolu Action you want to use. See
Releases for all
versions available. Each version of the Fourmolu Action generally has a
corresponding version of fourmolu
. Make sure you pick a Fourmolu Action
version that uses the version of fourmolu
you use locally.
Here's a full YAML file you can copy and paste into your repo that runs
fourmolu-action
. Add this as a file like .github/workflows/fourmolu.yaml
.
This Workflow will run everytime you push to a branch.
name: fourmolu
on: push
jobs:
format:
runs-on: ubuntu-latest
steps:
# Note that you must checkout your code before running fourmolu/fourmolu-action
- uses: actions/checkout@v2
- uses: fourmolu/fourmolu-action@v1
Here's a more complicated example that shows more options being used:
- uses: fourmolu/fourmolu-action@v1
with:
# Only check the format of .hs in the src/ directory.
pattern: |
src/**/*.hs
# Don't follow symbolic links to .hs files.
follow-symbolic-links: false
# Extra args to pass to fourmolu on the command line.
extra-args: "--indent-wheres true"
If you are using a build matrix, then it is more efficient to have a separate job for checking of formatting:
jobs:
fourmolu:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v2
- uses: fourmolu/fourmolu-action@v1
build:
runs-on: ubuntu-latest
needs: fourmolu
...
Here, the build
job depends on fourmolu
and will not run unless fourmolu
passes.
The available options are defined in ./action.yml
. See that
file for more explanation.
In order to do development on this repo, you first need to install NodeJS and
npm
to your system. This has been confirmed to work with the following
versions, but newer (or slightly older) versions may work as well:
- NodeJS: 14.19.1
npm
: 6.14.16
Next, clone this repo:
$ git clone git@github.com:fourmolu/fourmolu-action.git
Then, within this repo, install all dependencies defined in package.json
:
$ npm install
Now, you should be setup to start development. Development consists of hacking
on the ./index.js
file. After making changes to this file,
you'll need to regenerate the files in ./dist/
. You can do that
with the following command:
$ npm run prepare
When sending a PR, make sure to run npm run prepare
and commit the changes
to ./dist
whenever you make a change in ./index.js
.