binary-size.yml

name: Binary Size

on:
  push:
    branches: [main]
  pull_request:
    branches: [main]

concurrency:
  group: binary-size-${{ github.head_ref || github.ref }}
  cancel-in-progress: true

env:
  # Maximum allowed binary size in bytes (16MB = 16777216).
  #
  # Baseline: the CLI measured ~1.9MB until Aug 2026, when 8556d46 made
  # craft's first-party zig-js runtime part of the default build. That is a
  # deliberate subsystem, not bloat — see the js-runtime option in
  # packages/zig/build.zig (~+6.5MB in ReleaseFast; the ReleaseSafe binary
  # we ship and measure here lands at ~13.9MB, already stripped, with no
  # unwind tables or error traces). The gate sits ~15% above that baseline
  # so it still catches accidental growth; opt-out `-Djs-runtime=false`
  # builds remain around 2MB.
  MAX_BINARY_SIZE: 16777216
  # Warning threshold (14.5MB = 15204352), just above the ~13.9MB baseline
  # so creep surfaces as a warning well before the hard limit.
  WARN_BINARY_SIZE: 15204352

defaults:
  run:
    shell: bash

jobs:
  track:
    runs-on: ubuntu-latest

    # The last step posts the size report as a pull request comment, and the
    # default token here is read-only, so it failed with "Resource not
    # accessible by integration" — after the build and the measuring had all
    # succeeded. Requested explicitly rather than left to the repository
    # default, which is what made this invisible.
    permissions:
      contents: read
      pull-requests: write

    steps:
      - uses: actions/checkout@v6
        with:
          fetch-depth: 0

      - name: Setup Zig
        uses: pantry-pm/pantry/packages/action@235036fa0f48bae99b2293df5a3dc35c809b1777 # pinned: last SHA whose bundled typescript resolves on linux-x64
      - name: Install Linux dependencies
        run: |
          sudo apt-get update
          sudo apt-get install -y libgtk-3-dev libwebkit2gtk-4.1-dev

      - name: Cache Zig artifacts
        uses: actions/cache@v5
        with:
          path: |
            ~/.cache/zig
            packages/zig/zig-cache
          key: size-${{ runner.os }}-zig-master-${{ hashFiles('packages/zig/build.zig') }}
          restore-keys: |
            size-${{ runner.os }}-zig-master-

      - name: First-party Zig dependencies
        uses: ./.github/actions/first-party-zig-deps

      - name: Build release binary
        working-directory: packages/zig
        run: |
          zig build -Doptimize=ReleaseSafe

      - name: Measure binary size
        id: size
        working-directory: packages/zig
        run: |
          BINARY_PATH="zig-out/bin/craft"
          if [ -f "$BINARY_PATH" ]; then
            SIZE=$(wc -c < "$BINARY_PATH" | tr -d ' ')
            SIZE_KB=$((SIZE / 1024))
            SIZE_MB=$(echo "scale=2; $SIZE / 1048576" | bc)

            echo "size=$SIZE" >> $GITHUB_OUTPUT
            echo "size_kb=$SIZE_KB" >> $GITHUB_OUTPUT
            echo "size_mb=$SIZE_MB" >> $GITHUB_OUTPUT

            echo "Binary size: ${SIZE_KB}KB (${SIZE_MB}MB)"
          else
            echo "Binary not found at $BINARY_PATH"
            exit 1
          fi

      - name: Check size limits
        run: |
          SIZE=${{ steps.size.outputs.size }}
          SIZE_MB=${{ steps.size.outputs.size_mb }}

          if [ "$SIZE" -gt "$MAX_BINARY_SIZE" ]; then
            echo "::error::Binary size (${SIZE_MB}MB) exceeds maximum allowed size ($(echo "scale=2; $MAX_BINARY_SIZE / 1048576" | bc)MB)"
            exit 1
          elif [ "$SIZE" -gt "$WARN_BINARY_SIZE" ]; then
            echo "::warning::Binary size (${SIZE_MB}MB) is approaching the limit"
          fi

      - name: First-party Zig dependencies
        uses: ./.github/actions/first-party-zig-deps

      - name: Get baseline size (main branch)
        if: github.event_name == 'pull_request'
        id: baseline
        run: |
          git fetch origin main
          # Anchored at the workspace and `|| true`-guarded on purpose: the trap
          # fires at the end of the step, by which point `cd packages/zig` below
          # has moved us, so a relative pathspec resolves against the wrong
          # directory and fails. Under `set -e` that failing restore became the
          # step's exit status, so every pull request got a red Binary Size
          # check for a cleanup step rather than for its binary size.
          trap 'git -C "$GITHUB_WORKSPACE" restore --staged --worktree --source=HEAD -- packages/zig || true' EXIT
          git checkout origin/main -- packages/zig

          cd packages/zig
          zig build -Doptimize=ReleaseSafe

          if [ -f "zig-out/bin/craft" ]; then
            BASELINE=$(wc -c < "zig-out/bin/craft" | tr -d ' ')
            echo "baseline=$BASELINE" >> $GITHUB_OUTPUT
          else
            echo "::error::Baseline binary was not generated"
            exit 1
          fi

      - name: Calculate size difference
        if: github.event_name == 'pull_request'
        id: diff
        run: |
          CURRENT=${{ steps.size.outputs.size }}
          BASELINE=${{ steps.baseline.outputs.baseline }}

          if [ "$BASELINE" -gt 0 ]; then
            DIFF=$((CURRENT - BASELINE))
            DIFF_KB=$((DIFF / 1024))
            PERCENT=$(echo "scale=2; ($DIFF * 100) / $BASELINE" | bc)

            echo "diff=$DIFF" >> $GITHUB_OUTPUT
            echo "diff_kb=$DIFF_KB" >> $GITHUB_OUTPUT
            echo "percent=$PERCENT" >> $GITHUB_OUTPUT

            if [ "$DIFF" -gt 0 ]; then
              echo "direction=increased" >> $GITHUB_OUTPUT
            elif [ "$DIFF" -lt 0 ]; then
              echo "direction=decreased" >> $GITHUB_OUTPUT
            else
              echo "direction=unchanged" >> $GITHUB_OUTPUT
            fi
          fi

      - name: Generate size report
        run: |
          echo "## Binary Size Report" >> $GITHUB_STEP_SUMMARY
          echo "" >> $GITHUB_STEP_SUMMARY
          echo "| Metric | Value |" >> $GITHUB_STEP_SUMMARY
          echo "|--------|-------|" >> $GITHUB_STEP_SUMMARY
          echo "| Current Size | ${{ steps.size.outputs.size_kb }}KB (${{ steps.size.outputs.size_mb }}MB) |" >> $GITHUB_STEP_SUMMARY

          if [ "${{ github.event_name }}" == "pull_request" ] && [ "${{ steps.baseline.outputs.baseline }}" -gt 0 ]; then
            BASELINE_KB=$(( ${{ steps.baseline.outputs.baseline }} / 1024 ))
            echo "| Baseline (main) | ${BASELINE_KB}KB |" >> $GITHUB_STEP_SUMMARY
            echo "| Difference | ${{ steps.diff.outputs.diff_kb }}KB (${{ steps.diff.outputs.percent }}%) |" >> $GITHUB_STEP_SUMMARY
            echo "| Status | ${{ steps.diff.outputs.direction }} |" >> $GITHUB_STEP_SUMMARY
          fi

          echo "" >> $GITHUB_STEP_SUMMARY
          echo "### Limits" >> $GITHUB_STEP_SUMMARY
          echo "- Warning threshold: $(echo "scale=2; $WARN_BINARY_SIZE / 1048576" | bc)MB" >> $GITHUB_STEP_SUMMARY
          echo "- Maximum allowed: $(echo "scale=2; $MAX_BINARY_SIZE / 1048576" | bc)MB" >> $GITHUB_STEP_SUMMARY

      - name: Comment on PR
        if: github.event_name == 'pull_request'
        uses: actions/github-script@v7
        with:
          script: |
            const size = '${{ steps.size.outputs.size_kb }}';
            const sizeMB = '${{ steps.size.outputs.size_mb }}';
            const diff = '${{ steps.diff.outputs.diff_kb }}';
            const percent = '${{ steps.diff.outputs.percent }}';
            const direction = '${{ steps.diff.outputs.direction }}';
            const warnMB = (Number(process.env.WARN_BINARY_SIZE) / 1048576).toFixed(2);
            const maxMB = (Number(process.env.MAX_BINARY_SIZE) / 1048576).toFixed(2);

            let emoji = '✅';
            if (direction === 'increased' && parseInt(diff) > 10) emoji = '⚠️';
            if (direction === 'decreased') emoji = '📉';

            const body = `## ${emoji} Binary Size Report

            | Metric | Value |
            |--------|-------|
            | Current Size | ${size}KB (${sizeMB}MB) |
            | Change | ${diff}KB (${percent}%) ${direction} |

            <details>
            <summary>Size limits</summary>

            - Warning: ${warnMB}MB
            - Maximum: ${maxMB}MB
            </details>`;

            // Find existing comment
            const { data: comments } = await github.rest.issues.listComments({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: context.issue.number,
            });

            const existingComment = comments.find(c =>
              c.user.login === 'github-actions[bot]' &&
              c.body.includes('Binary Size Report')
            );

            if (existingComment) {
              await github.rest.issues.updateComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                comment_id: existingComment.id,
                body: body
              });
            } else {
              await github.rest.issues.createComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: context.issue.number,
                body: body
              });
            }

      - name: Restore size history
        if: github.ref == 'refs/heads/main'
        continue-on-error: true
        env:
          GH_TOKEN: ${{ github.token }}
        run: |
          # The history file lives only in the uploaded artifact (never in the
          # repo), so pull the previous run's copy before appending — without
          # this each artifact holds a single entry and no history accumulates.
          mkdir -p .github/metrics
          PREV_RUN=$(gh run list --workflow "Binary Size" --branch main --status success --limit 1 --json databaseId --jq '.[0].databaseId // empty')
          if [ -n "$PREV_RUN" ]; then
            gh run download "$PREV_RUN" -n binary-size-metrics -D .github/metrics || true
          fi

      - name: Save size history
        if: github.ref == 'refs/heads/main'
        run: |
          mkdir -p .github/metrics
          DATE=$(date -u +%Y-%m-%d)
          COMMIT=$(git rev-parse --short HEAD)

          echo "{\"date\": \"$DATE\", \"commit\": \"$COMMIT\", \"size\": ${{ steps.size.outputs.size }}}" >> .github/metrics/binary-size.jsonl

      - name: Upload metrics
        if: github.ref == 'refs/heads/main'
        uses: actions/upload-artifact@v4
        with:
          name: binary-size-metrics
          path: .github/metrics/
          retention-days: 90