GitHub actions is a very useful service that is provided free to public and private repositories. It allows you to automatically run commands or *actions* when an event happens.

To find errors, we'll be using the push and pull_request events.

First of all, create a file called error_action.yml in .github/workflows/ where your git repository is.

Put the following inside:

error_action.yml

name: Gradle Error Checker

on: [ push, pull_request ]
jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v2
        with:
          fetch-depth: 0

This will run the Checkout step when a pull request is made or a commit is push. However, we want it to lint our code and find those darn errors.

Luckily for us, GitHub has a built in tool that can help us with that called SuperLinter.

To add super linter, add the following underneath the Checkout step.

- name: Check for errors.
        uses: github/super-linter@v3
        env:
          VALIDATE_ALL_CODEBASE: false

The VALIDATE_ALL_CODEBASE: false option makes sure we dont waste our time linting stuff that has already been checked. Superlinter will only check the files that have been changed in the commit or pull request. You can set this to true if you want to check the entire code.

Now, if an error is found. Github reports it to us!

Aha! GitHub has found an error for us!

/home/runner/work/MyRepo/MyMod/src/main/java/com/mymod/blocks/MyModBlocks.java:65: error: variable RAINBOW_GRASS not initialized in the default constructor
    public static final Block RAINBOW_GRASS;