Style modified files in a project (non package)

[Moohan]

It would be great to have a few more example templates that can work generically on R projects that aren't packages. For example, styling or lining etc. I've developed a 'style modified files' workflow that works for me but I'm sure can be improved by people more technically competent!

name: Style Modified Files

on:
  pull_request_target: # Triggers when code is pushed to a PR's target branch
    types: [opened, synchronize, reopened]
    
permissions: write-all

jobs:
  style_check:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          ref: ${{ github.event.pull_request.head.ref }} 
          fetch-depth: 0  # Fetch full history for accurate diff

      - name: Setup R
        uses: r-lib/actions/setup-r@v2
        with:
          use-public-rspm: true
        
      - name: Install pak (will install any system dependencies too)
        run: install.packages("pak")
        shell: Rscript {0}

      - name: Install styler and other packages
        run: pak::pkg_install(pkg = c("styler", "purrr", "gh"), dependencies = TRUE)
        shell: Rscript {0}

      - name: Enable styler cache
        run: styler::cache_activate()
        shell: Rscript {0}

      - name: Determine cache location
        id: styler-location
        run: |
          cat(
            "location=",
            styler::cache_info(format = "tabular")$location,
            "\n",
            file = Sys.getenv("GITHUB_OUTPUT"),
            append = TRUE,
            sep = ""
          )
        shell: Rscript {0}

      - name: Cache styler
        uses: actions/cache@v4
        with:
          path: ${{ steps.styler-location.outputs.location }}
          key: ${{ runner.os }}-styler-${{ github.sha }}
          restore-keys: |
            ${{ runner.os }}-styler-
            ${{ runner.os }}-

      - name: Style modified R files
        run: |
          files <- gh::gh("GET https://api.github.com/repos/${{ github.repository }}/pulls/${{ github.event.pull_request.number }}/files")
          changed_files <- purrr::map_chr(files, "filename")
          all_files <- list.files(recursive = TRUE)
          exclusions <- setdiff(all_files, changed_files)
          styler::style_dir(exclude_files = exclusions)
        shell: Rscript {0}

      - name: Commit and push changes
        uses: stefanzweifel/git-auto-commit-action@v5
        with:
          commit_message: "Style code"
          skip_checkout: true