dependency-change.yaml

# Workflow derived from https://github.com/r-lib/actions/tree/v2/examples
# Need help debugging build failures? Start at https://github.com/r-lib/actions#where-to-find-help
on:
  pull_request:
    paths:
      - 'DESCRIPTION'

name: Analyze dependency changes

concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

permissions:
  pull-requests: write

jobs:
  dependency-changes:
    runs-on: ubuntu-latest
    env:
      GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
    steps:
      - name: Setup R
        uses: r-lib/actions/setup-r@v2
        with:
          use-public-rspm: true

      - name: Install dependencies
        uses: r-lib/actions/setup-r-dependencies@v2
        with:
          packages: any::pak, glue, gh

      - name: Analyze dependency changes
        shell: Rscript {0}
        run: |
          deps_base <- pak::pkg_deps("${{ github.repository }}@${{ github.base_ref }}", dependencies = TRUE) |>
            subset(!directpkg) |>
            subset(is.na(priority))
          # We install from PR number rather than branch to deal with the case
          # of PR coming from forks
          deps_head <- pak::pkg_deps("${{ github.repository }}#${{ github.event.number }}", dependencies = TRUE) |>
            subset(!directpkg) |>
            subset(is.na(priority))

          deps_added <- deps_head |>
            subset(!ref %in% deps_base$ref)

          deps_removed <- deps_base |>
            subset(!ref %in% deps_head$ref)

          if (nrow(deps_added) + nrow(deps_removed) > 0) {

            message("Dependencies have changed! Analyzing...")

            if (nrow(deps_added) > 0) {
              nudge <- "Reach out on slack (`#code-review` or `#help` channels) to double check if there are base R alternatives to the new dependencies.\n"
            } else {
              nudge <- ""
            }

            msg <- glue::glue(
              .sep = "\n",
              "This pull request:",
              "- Adds {nrow(deps_added)} new dependencies (direct and indirect)",
              "- Adds {length(unique(deps_added$sysreqs))} new system dependencies",
              "- Removes {nrow(deps_removed)} existing dependencies (direct and indirect)",
              "- Removes {length(unique(deps_removed$sysreqs))} existing system dependencies",
              "",
              nudge,
              "(Note that results may be inaccurate if you branched from an outdated version of the target branch.)"
            )

            message("Posting results as a pull request comment.")

            gh::gh(
              "POST /repos/{repo}/issues/{issue_number}/comments",
              repo = "${{ github.repository }}",
              issue_number = "${{ github.event.number }}",
              body = msg
            )

          }