Monorepo CI Gate

name: monorepo-ci
desc: "Build and test only the packages affected by the last commit, then gate the merge"

defaults:
  repo: "./mono"
  all_packages:
    - "api"
    - "web"
    - "shared"

tasks:
  setup_demo_monorepo:
    desc: "Create a demo monorepo with three packages (demo helper)"
    steps:
      - name: scaffold
        func: shell
        do: |
          rm -rf {{ vars.repo }}
          mkdir -p {{ vars.repo }}/packages/{api,web,shared}
          cd {{ vars.repo }}
          git init -q -b main
          git config user.email ci@orchstep.dev && git config user.name "CI Demo"
          for p in api web shared; do
            cat > packages/$p/build.sh <<S
          #!/bin/sh
          echo "building $p"
          S
            cat > packages/$p/test.sh <<S
          #!/bin/sh
          echo "testing $p: 12 passed"
          S
            chmod +x packages/$p/*.sh
          done
          git add -A && git commit -qm "baseline"
          echo "fix" >> packages/api/build.sh
          git add -A && git commit -qm "fix api build flags"
          echo "monorepo ready"

  ci:
    desc: "Affected-only pipeline: detect -> plan -> build+test each -> gate"
    steps:
      - name: detect_changes
        desc: "Which packages did the last commit touch?"
        func: shell
        do: |
          cd {{ vars.repo }}
          git diff --name-only HEAD~1 HEAD | awk -F/ '/^packages\// {print $2}' | sort -u | tr '\n' ' '
        outputs:
          changed: "{{ result.output }}"

      - name: plan
        desc: "Expand to affected set: anything touching shared affects everyone"
        func: transform
        do: |
          const changed = steps.detect_changes.changed.trim().split(/\s+/).filter(Boolean);
          const all = ["api", "web", "shared"];
          const targets = changed.includes("shared") ? all : changed;
          // loop items cannot read steps.* (vars only), so the loop below
          // iterates every package and skips the unaffected ones - which is
          // also what you want in CI logs.
          return { targets: targets, count: targets.length, summary: targets.join(" ") };

      - name: build_and_test
        desc: "Run every affected package's pipeline; skip the rest"
        loop:
          items: "{{ vars.all_packages }}"
          as: pkg
        func: shell
        do: |
          case " {{ steps.plan.summary }} " in
            *" {{ loop.pkg }} "*)
              cd {{ vars.repo }}/packages/{{ loop.pkg }}
              ./build.sh && ./test.sh
              echo "pkg={{ loop.pkg }} result=pass" ;;
            *)
              echo "pkg={{ loop.pkg }} result=skip (not affected)" ;;
          esac
        outputs:
          pkg: "{{ loop.pkg }}"
          result: '{{ result.output | regexFind "result=([a-z]+)" }}'

      - name: repo_wide_checks
        desc: "Cheap repo-wide checks always run, in parallel"
        parallel:
          - name: lint_shell
            func: shell
            do: |
              cd {{ vars.repo }}
              sh -n packages/*/build.sh packages/*/test.sh && echo "lint=ok"
            outputs:
              ok: '{{ result.output | regexFind "lint=([a-z]+)" }}'
          - name: forbid_todo
            func: shell
            do: |
              cd {{ vars.repo }}
              ! grep -rn "TODO-BLOCKER" packages/ && echo "todo=clean"
            outputs:
              ok: '{{ result.output | regexFind "todo=([a-z]+)" }}'

      - name: gate
        func: assert
        args:
          conditions:
            - condition: "steps.build_and_test.outputs.every(o => o.result === 'pass' || o.result === 'skip')"
              desc: "every affected package built and tested clean"
            - condition: '{{ eq steps.lint_shell.ok "ok" }}'
            - condition: '{{ eq steps.forbid_todo.ok "clean" }}'

      - name: report
        func: shell
        do: 'echo "CI_PASS affected=[{{ steps.plan.summary }}] packages={{ steps.plan.count }}"'

orchstep run setup_demo_monorepo    # 3 packages; last commit touches api
orchstep run ci

# last commit touched api only
CI_PASS affected=[api] packages=1        (web, shared skipped)

# after a commit touching shared
CI_PASS affected=[api web shared] packages=3

# after a commit containing "TODO-BLOCKER"
exit 1 - gate fails on the forbid_todo check