Add benchmarking script and CI using PHPBench

.github/workflows/benchmark.yml

@@ -0,0 +1,75 @@
+name: Benchmark
+
+on:
+  pull_request:
+    branches: [main]
+
+permissions:
+  pull-requests: write
+
+jobs:
+  benchmark:
+    name: Performance Regression Check
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout PR branch
+        uses: actions/checkout@v6
+        with:
+          fetch-depth: 0
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: 8.4
+          extensions: dom, curl, libxml, mbstring, zip, pcntl, pdo, sqlite, pdo_sqlite, bcmath, soap, intl, gd, exif, iconv, imagick, fileinfo
+          coverage: none
+
+      - name: Install dependencies
+        uses: ramsey/composer-install@v3
+
+      - name: Benchmark base branch
+        run: |
+          git checkout ${{ github.event.pull_request.base.sha }}
+          composer install --no-interaction --prefer-dist --quiet
+          vendor/bin/phpbench run --tag=base --store --progress=dots
+
+      - name: Benchmark PR branch
+        run: |
+          git checkout ${{ github.event.pull_request.head.sha }}
+          composer install --no-interaction --prefer-dist --quiet
+          vendor/bin/phpbench run --tag=pr --store --ref=base --report=aggregate --progress=dots > benchmark-result.txt 2>&1 || true
+
+      - name: Read benchmark result
+        id: bench
+        run: |
+          {
+            echo "result<<BENCH_EOF"
+            cat benchmark-result.txt
+            echo "BENCH_EOF"
+          } >> "$GITHUB_OUTPUT"
+
+      - name: Find existing comment
+        uses: peter-evans/find-comment@v4
+        id: find-comment
+        with:
+          issue-number: ${{ github.event.pull_request.number }}
+          comment-author: github-actions[bot]
+          body-includes: "## Benchmark Results"
+
+      - name: Post benchmark results
+        uses: peter-evans/create-or-update-comment@v5
+        with:
+          issue-number: ${{ github.event.pull_request.number }}
+          comment-id: ${{ steps.find-comment.outputs.comment-id }}
+          edit-mode: replace
+          body: |
+            ## Benchmark Results
+
+            Comparison of `${{ github.head_ref }}` against `${{ github.base_ref }}` (`${{ github.event.pull_request.base.sha }}`).
+
+            ```
+            ${{ steps.bench.outputs.result }}
+            ```
+
+            <sub>Generated by phpbench against commit ${{ github.event.pull_request.head.sha }}</sub>

.gitignore

@@ -2,6 +2,7 @@
 .phpunit.result.cache
 composer.lock
 /.php-cs-fixer.cache
+.phpbench/
 .env
 .idea
-build/
+build/