auto_snapshot_update.yml

# Experimental workflow to automate updating to a new Minecraft snapshot.

# Currently this is very similar to the semi-automatic scripts I already use,
# but moving them to GitHub Actions means I don't have to be around to start
# them. This should allow for further automation in the future.

# TODO:
# - Add more thorough automated testing where it runs the game, creates a test
#   world and takes screenshots, similar to what Fabric API does in their
#   GitHub Actions workflow.
# - Set up a server to trigger this workflow when a new snapshot is out and
#   Fabric has updated to it. This might end up running twice per snapshot,
#   because there is no way to know ahead of time if the previous Fabric API
#   build still works or if we have to wait for a new build made specifically
#   for the new snapshot.
# - Add a step to automatically release the new snapshot build if all tests
#   have passed. This will only ever run on small snapshots that don't break
#   anything, but should save a ton of time at the end of each snapshot cycle
#   when Mojang is spamming tiny pre-releases every day.

# In case it isn't obvious, these todos are very ambitious and might not end
# up working as planned.

name: Auto Snapshot Update

on:
  workflow_dispatch:
    inputs:
      mc_version:
        description: "Minecraft version to update to"
        required: true
      yarn_mappings:
        description: "Yarn mappings version"
        required: true
      fabric_loader:
        description: "Fabric Loader version"
        required: true
      fapi_version:
        description: "Fabric API version"
        required: true
      distinct_id:
        description: "Automatically set by the return-dispatch action (leave blank if running manually)"
        required: false

permissions:
  # To push changes to the new snapshot branch.
  contents: write
  # To trigger the CI workflow.
  actions: write

jobs:
  update:
    runs-on: ubuntu-latest
    steps:

    - name: Echo distinct ID ${{ github.event.inputs.distinct_id }}
      run: echo ${{ github.event.inputs.distinct_id }}

    - name: Checkout repository
      uses: actions/checkout@v4
      with:
        # Include all branches in case the new snapshot branch already exists.
        fetch-depth: 0

    - name: Set up Python 3.12
      uses: actions/setup-python@v5
      with:
        python-version: "3.12"

    - name: Set up Java 21
      uses: actions/setup-java@v4
      with:
        java-version: "21"
        distribution: "microsoft"

    - name: Grant execute permission for gradlew
      run: chmod +x gradlew

    - name: Setup Gradle
      uses: gradle/actions/setup-gradle@v4
      with:
        build-scan-publish: true
        build-scan-terms-of-use-url: "https://gradle.com/help/legal-terms-of-use"
        build-scan-terms-of-use-agree: "yes"

    - name: Create and checkout new snapshot branch
      run: |
        BRANCH_NAME="${{ github.event.inputs.mc_version }}"
        CURRENT_BRANCH=$(git rev-parse --abbrev-ref HEAD)
        
        if [ "$CURRENT_BRANCH" = "$BRANCH_NAME" ]; then
          echo "Already on branch $BRANCH_NAME. Skipping branch creation."
        elif git show-ref --quiet refs/heads/$BRANCH_NAME; then
          echo "Branch $BRANCH_NAME already exists but is not currently checked out. Failing the workflow."
          exit 1
        else
          git checkout -b $BRANCH_NAME
          echo "Created and checked out new branch: $BRANCH_NAME"
        fi
      shell: bash

    - name: Run migrateMappings task
      run: |
        ./gradlew migrateMappings --mappings ${{ github.event.inputs.yarn_mappings }}
      shell: bash

    - name: Replace src/main/java with remapped files
      run: |
        rm -rf ./src/main/java
        mv ./remappedSrc ./src/main/java
      shell: bash

    - name: Update version constants
      run: |
        python scripts/update_version_constants.py "${{ github.event.inputs.mc_version }}" "${{ github.event.inputs.yarn_mappings }}" "${{ github.event.inputs.fabric_loader }}" "${{ github.event.inputs.fapi_version }}"
      shell: bash

    # To fix any style issues that the migration scripts might cause
    - name: Run spotlessApply task
      run: ./gradlew spotlessApply

    - name: Commit and push changes
      run: |
        git config --global user.name "Wurst-Bot"
        git config --global user.email "contact.wurstimperium@gmail.com"
        git add .
        git commit -m "[Wurst-Bot] Update to ${{ github.event.inputs.mc_version }}"
        git push --set-upstream origin ${{ github.event.inputs.mc_version }}
      shell: bash

    # For some reason the commit above doesn't automatically trigger the CI
    # workflow, so we need to explicitly start it here.
    - name: Trigger CI on the new branch
      env:
        GH_TOKEN: ${{ github.token }}
      run: |
        gh workflow run gradle.yml --ref ${{ github.event.inputs.mc_version }}
      shell: bash