auto-label-prs.yml

name: Auto-label PRs

# PR labeling has two parts:
#
#   1. `paths` job — runs actions/labeler against .github/labeler.yml to
#      apply [Aspect], [Focus], [Feature], and [Type] Documentation
#      labels. These have no count limit and a wide refactor can match
#      many of them legitimately.
#
#   2. `package-and-type` job — applies the `[Package][...]` labels and
#      a single inferred `[Type]` label. This one needs custom logic:
#
#        - [Package]: ranks packages by total lines changed
#          (additions + deletions, file count as tiebreaker) and applies
#          at most the top 3. Without this cap, a cross-cutting change
#          ends up with a wall of package labels and the signal is lost.
#
#        - [Type]: parses the PR title's conventional-commit prefix
#          (fix:/feat:/perf:) and applies one matching label only when
#          the signal is unambiguous. We skip refactor:/chore:/test:
#          because they have no clean target label.
#
# History note: an earlier version used GitHub Models (actions/ai-inference)
# to suggest labels from PR title + body + paths. That returned 403
# because GitHub Models access in Actions is gated by an org-level toggle
# we can't flip. Path + PR-title heuristics cover the structured labels
# without any external service.

on:
    pull_request_target:
        types: [opened, synchronize, reopened, ready_for_review]

# Disable permissions for all available scopes by default.
# Any needed permissions should be configured at the job level.
permissions: {}

jobs:
    paths:
        if: github.repository == 'WordPress/wordpress-playground'
        runs-on: ubuntu-latest
        timeout-minutes: 10
        permissions:
            contents: read # Required for actions/labeler to read the configuration file.
            pull-requests: write # Required to apply labels to pull requests.
        steps:
            # Pinned to a commit SHA, not a tag: this job runs with
            # pull-requests:write, so a moved tag would be a supply-chain
            # foothold. Bump deliberately when upgrading.
            - uses: actions/labeler@8558fd74291d67161a8a78ce36a881fa63b766a9 # v5.0.0
              with:
                  configuration-path: .github/labeler.yml
                  sync-labels: false

    package-and-type:
        if: github.repository == 'WordPress/wordpress-playground'
        runs-on: ubuntu-latest
        timeout-minutes: 10
        permissions:
            pull-requests: write # Required to apply labels to pull requests.
        steps:
            - uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1
              with:
                  script: |
                      // Path prefix → [Package][...] label. Order matters: the
                      // first matching prefix wins, so longer / more specific
                      // prefixes must come before shorter ones (e.g. `web-service-worker`
                      // before `web`).
                      const PACKAGE_RULES = [
                          ['packages/php-wasm/cli-util/',          '[Package][@php-wasm] CLI-Util'],
                          ['packages/php-wasm/cli/',               '[Package][@php-wasm] CLI'],
                          ['packages/php-wasm/compile/',           '[Package][@php-wasm] Compile'],
                          ['packages/php-wasm/fs-journal/',        '[Package][@php-wasm] FS Journal'],
                          ['packages/php-wasm/logger/',            '[Package][@php-wasm] Logger'],
                          ['packages/php-wasm/node/',              '[Package][@php-wasm] Node'],
                          ['packages/php-wasm/progress/',          '[Package][@php-wasm] Progress'],
                          ['packages/php-wasm/scopes/',            '[Package][@php-wasm] Scopes'],
                          ['packages/php-wasm/stream-compression/','[Package][@php-wasm] Stream Compression'],
                          ['packages/php-wasm/universal/',         '[Package][@php-wasm] Universal'],
                          ['packages/php-wasm/util/',              '[Package][@php-wasm] Util'],
                          ['packages/php-wasm/web-service-worker/','[Package][@php-wasm] Web'],
                          ['packages/php-wasm/web/',               '[Package][@php-wasm] Web'],
                          ['packages/php-wasm/xdebug-bridge/',     '[Package][@php-wasm] Xdebug Bridge'],
                          ['packages/playground/blueprints/',      '[Package][@wp-playground] Blueprints'],
                          ['packages/playground/cli/',             '[Package][@wp-playground] CLI'],
                          ['packages/playground/client/',          '[Package][@wp-playground] Client'],
                          ['packages/playground/common/',          '[Package][@wp-playground] Common'],
                          ['packages/playground/components/',      '[Package][@wp-playground] Components'],
                          ['packages/playground/php-cors-proxy/',  '[Package][@wp-playground] CORS Proxy'],
                          ['packages/playground/remote/',          '[Package][@wp-playground] Remote'],
                          ['packages/playground/storage/',         '[Package][@wp-playground] Storage'],
                          ['packages/playground/sync/',            '[Package][@wp-playground] Sync'],
                          ['packages/playground/website-extras/',  '[Package][@wp-playground] Website'],
                          ['packages/playground/website/',         '[Package][@wp-playground] Website'],
                          ['packages/playground/wordpress-builds/','[Package][@wp-playground] WordPress Builds'],
                          ['packages/playground/wordpress/',       '[Package][@wp-playground] WordPress'],
                      ];

                      // Conventional-commit prefix → [Type] label. Only entries
                      // with an unambiguous target label are listed; refactor /
                      // chore / test / build / ci are intentionally absent.
                      const TYPE_RULES = [
                          [/^fix(\(|:)/i,      '[Type] Bug'],
                          [/^feat(ure)?(\(|:)/i, '[Type] Enhancement'],
                          [/^perf(\(|:)/i,     '[Type] Performance'],
                          [/^docs(\(|:)/i,     '[Type] Documentation'],
                      ];

                      const pr = context.payload.pull_request;

                      // Very large PRs (e.g. recompiled WASM binaries) make
                      // GitHub's diff generation time out, so listFiles returns
                      // 422 "Sorry, this diff is taking too long to generate."
                      // That failure is persistent for such PRs — retrying just
                      // loads their servers without helping. Package/type labels
                      // are cosmetic, so skip them rather than fail the job.
                      let files;
                      try {
                          files = await github.paginate(
                              github.rest.pulls.listFiles,
                              { owner: context.repo.owner, repo: context.repo.repo, pull_number: pr.number, per_page: 100 }
                          );
                      } catch (err) {
                          const status = err?.status;
                          const message = err?.message ?? String(err);

                          if (status !== 422 || !/diff is taking too long to generate/i.test(message)) {
                              throw err;
                          }

                          core.warning(
                              `Could not list PR files (status ${status}): ${message}. ` +
                              `Skipping package/type labeling for this PR.`
                          );
                          return;
                      }

                      // Tally lines + file count per package label.
                      const stats = new Map();
                      for (const f of files) {
                          const rule = PACKAGE_RULES.find(([prefix]) => f.filename.startsWith(prefix));
                          if (!rule) continue;
                          const label = rule[1];
                          const lines = (f.additions || 0) + (f.deletions || 0);
                          const cur = stats.get(label) || { lines: 0, files: 0 };
                          stats.set(label, { lines: cur.lines + lines, files: cur.files + 1 });
                      }

                      // Rank: lines desc, then file count desc, then label name
                      // for stable output.
                      const topPackages = [...stats.entries()]
                          .sort(([a, sa], [b, sb]) =>
                              sb.lines - sa.lines ||
                              sb.files - sa.files ||
                              a.localeCompare(b)
                          )
                          .slice(0, 3)
                          .map(([label]) => label);

                      const labels = [...topPackages];
                      const titleMatch = TYPE_RULES.find(([re]) => re.test(pr.title));
                      if (titleMatch) labels.push(titleMatch[1]);

                      core.info(`PR title: ${pr.title}`);
                      core.info(`Package stats: ${JSON.stringify([...stats])}`);
                      core.info(`Applying labels: ${JSON.stringify(labels)}`);

                      if (labels.length === 0) return;
                      await github.rest.issues.addLabels({
                          owner: context.repo.owner,
                          repo: context.repo.repo,
                          issue_number: pr.number,
                          labels,
                      });