name: smart-byte conformance gate

# One run per branch at a time. A push supersedes the run before it.
#
# There is one `macos` runner and it is the dev Mac, so every macOS job in this
# repo queues on it. With no concurrency group, a session pushing four versions
# of a branch queued four complete sets of runs and every one of them had to
# drain: on 2026-10-05 a PR's 21 contexts settled none in 70 minutes behind a
# backlog of 25 runs, and the queue grew faster than it cleared. Only the newest
# commit's verdict is wanted, so the older runs are cancelled.
#
# Verified on this forge (Forgejo 16.0.5) in `ci-test` before being added here:
# the key parses, and a newer push moves an older run to `cancelled` even while
# it is still queued, which is the case that matters.
#
# `cancel-in-progress: true` also applies to `main`. That is deliberate and
# safe here: main advances by merge commits whose tree contains the commits
# before them, so the newer run covers the older one's changes.
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

on:
  pull_request:
    paths:
      - 'smart-byte/spec/**'
      - 'smart-byte/conformance/**'
      - '.github/workflows/conformance.yml'
  push:
    branches:
      - main
    paths:
      - 'smart-byte/spec/**'
      - 'smart-byte/conformance/**'
      - '.github/workflows/conformance.yml'

jobs:
  # Does this pull request's own diff touch the paths below? This forge matches a
  # workflow's `paths:` against the push, so a merge of main into a branch fires the
  # workflow whatever the pull request changes; every job here waits on this answer.
  # A push to main, a schedule, or anything the script cannot determine answers
  # `true` (scripts/pr-touches-paths.py).
  relevant:
    name: does this change touch it
    runs-on: gate
    outputs:
      run: ${{ steps.gate.outputs.run }}
    steps:
      - uses: actions/checkout@v5
        with:
          fetch-depth: 0
      - id: gate
        run: |
          set -euo pipefail
          r=$(python3 scripts/pr-touches-paths.py .github/workflows/conformance.yml \
                "${{ github.event.pull_request.base.sha }}" \
                "${{ github.event.pull_request.head.sha }}")
          echo "this change touches conformance: $r"
          echo "run=$r" >> "$GITHUB_OUTPUT"

  validate-json:
    needs: relevant
    if: needs.relevant.outputs.run == 'true'
    name: Validate conformance JSON files
    runs-on: linux
    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Ensure jq is available
        run: jq --version

      - name: Validate every JSON file under smart-byte/conformance/v*
        run: |
          set -euo pipefail
          found=0
          fail=0
          while IFS= read -r -d '' f; do
            found=$((found+1))
            if ! jq empty "$f" >/dev/null 2>&1; then
              echo "::error file=$f::invalid JSON"
              fail=$((fail+1))
            else
              echo "ok: $f"
            fi
          done < <(find smart-byte/conformance -type f -name '*.json' -print0)
          if [ "$found" -eq 0 ]; then
            echo "::error::no JSON files found under smart-byte/conformance/v*"
            exit 1
          fi
          if [ "$fail" -ne 0 ]; then
            echo "::error::$fail JSON file(s) failed validation"
            exit 1
          fi
          echo "validated $found JSON file(s)"

      - name: Validate vector schema (top-level array, name field present)
        run: |
          set -euo pipefail
          fail=0
          while IFS= read -r -d '' f; do
            if ! jq -e 'type == "array"' "$f" >/dev/null; then
              echo "::error file=$f::top-level value must be a JSON array"
              fail=$((fail+1))
              continue
            fi
            if ! jq -e 'all(.[]; has("name") and has("description"))' "$f" >/dev/null; then
              echo "::error file=$f::every vector must have name and description fields"
              fail=$((fail+1))
            fi
          done < <(find smart-byte/conformance -type f -name '*_vectors.json' -print0)
          if [ "$fail" -ne 0 ]; then
            echo "::error::$fail vector file(s) failed schema validation"
            exit 1
          fi

      - name: Validate vector names are unique within each file
        run: |
          set -euo pipefail
          fail=0
          while IFS= read -r -d '' f; do
            dupes=$(jq -r '[.[].name] | group_by(.) | map(select(length>1)) | .[][0] // empty' "$f")
            if [ -n "$dupes" ]; then
              echo "::error file=$f::duplicate vector name(s): $dupes"
              fail=$((fail+1))
            fi
          done < <(find smart-byte/conformance -type f -name '*_vectors.json' -print0)
          if [ "$fail" -ne 0 ]; then
            exit 1
          fi

  # The pack's values come from the Rust reference implementation, and
  # standards-build checks them against it under `cargo test`. This job checks
  # them against a second implementation, written separately in another
  # language, so a mistake shared by the generator and its own verifier still
  # fails here. Standard library only: nothing to install beyond python3.
  crosscheck:
    needs: relevant
    if: needs.relevant.outputs.run == 'true'
    name: Second implementation reproduces every vector
    runs-on: linux
    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Ensure python3 is available
        shell: bash
        run: |
          if ! command -v python3 >/dev/null 2>&1; then
            SUDO=""; [ "$(id -u)" -ne 0 ] && SUDO="sudo"
            $SUDO apt-get update -qq
            $SUDO apt-get install -y -qq python3
          fi
          python3 --version

      - name: Cross-check v1
        run: python3 smart-byte/conformance/crosscheck/verify_v1.py smart-byte/conformance/v1

  spec-vector-coupling:
    needs: relevant
    if: needs.relevant.outputs.run == 'true' && (github.event_name == 'pull_request')
    name: Spec changes require vector-pack updates
    runs-on: linux
    steps:
      - name: Checkout (with full history for diff)
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Determine the PR base
        id: base
        run: |
          base="${{ github.event.pull_request.base.sha }}"
          if [ -z "$base" ]; then
            base="origin/main"
          fi
          echo "base=$base" >> "$GITHUB_OUTPUT"

      - name: Enforce coupling between spec and conformance changes
        run: |
          set -euo pipefail
          base="${{ steps.base.outputs.base }}"
          head="${{ github.event.pull_request.head.sha }}"
          if [ -z "$head" ]; then
            head="HEAD"
          fi
          changed=$(git diff --name-only "$base" "$head")
          echo "Files changed in this PR:"
          echo "$changed"
          spec_touched=0
          conformance_touched=0
          if echo "$changed" | grep -qE '^smart-byte/spec/'; then
            spec_touched=1
          fi
          if echo "$changed" | grep -qE '^smart-byte/conformance/'; then
            conformance_touched=1
          fi
          if [ "$spec_touched" -eq 1 ] && [ "$conformance_touched" -eq 0 ]; then
            echo "::error::This PR modifies smart-byte/spec/ without modifying smart-byte/conformance/."
            echo "::error::Per the conformance social contract, every spec change must be accompanied by a vector-pack update."
            echo "::error::If the spec change is editorial and the wire format is unchanged, record the editorial reason in smart-byte/conformance/v<N>/regeneration.md and include that file in the PR."
            exit 1
          fi
          echo "coupling check passed (spec_touched=$spec_touched, conformance_touched=$conformance_touched)"

  versions-present:
    needs: relevant
    if: needs.relevant.outputs.run == 'true'
    name: VERSIONS.md and README.md must exist
    runs-on: linux
    steps:
      - name: Checkout
        uses: actions/checkout@v4
      - name: Required pack metadata files
        run: |
          set -euo pipefail
          missing=0
          for f in smart-byte/conformance/README.md smart-byte/conformance/VERSIONS.md; do
            if [ ! -f "$f" ]; then
              echo "::error file=$f::missing required pack metadata file"
              missing=$((missing+1))
            fi
          done
          for d in smart-byte/conformance/v*/ ; do
            if [ ! -f "$d/regeneration.md" ]; then
              echo "::error file=$d/regeneration.md::missing regeneration.md for $d"
              missing=$((missing+1))
            fi
          done
          if [ "$missing" -ne 0 ]; then
            exit 1
          fi