Allow panda.yml to request benchmark runs for PRs

This change introduces a new command to `@TheRespectPanda` bot,
allowing him to dispatch the ci-perf.yml workflow benchmarks for
a pull request.

Initially, the bot will just trigger it and return the workflow
run URL for manual inspection. Future iterations on this feature
could then grab the benchmark results and update the comment.

Author: alganet

.github/workflows/ci-perf.yml

@@ -21,6 +21,9 @@ on:
         options:
           - 'latest'
           - 'rebaseline'
+      pull:
+        description: 'Pull request number to benchmark (optional)'
+        required: false
 
 jobs:
   tests:
@@ -34,6 +37,18 @@ jobs:
       - uses: actions/checkout@v6
         with:
           persist-credentials: true
+
+      - name: Checkout PR head (if requested)
+        if: ${{ github.event.inputs.pull }}
+        run: |
+          set -euo pipefail
+          PR=${{ github.event.inputs.pull }}
+          # fetch the pull request head (works for forks)
+          git fetch origin pull/${PR}/head:pr-${PR} || git fetch origin +refs/pull/${PR}/head:pr-${PR}
+          git checkout pr-${PR}
+          echo "Checked out PR #${PR}"
+          echo "GITHUB_SHA=$(git rev-parse --verify HEAD)" >> $GITHUB_ENV
+
       - uses: ./.github/actions/setup-action
         with:
           extensions: xdebug

.github/workflows/panda.yml

@@ -11,13 +11,14 @@ jobs:
     permissions:
       issues: write
       pull-requests: write
+      actions: write
     steps:
       - uses: actions/github-script@v8
         with:
           github-token: ${{ secrets.PANDA_GITHUB_PAT }}
           script: |
             const body = (context.payload.comment && context.payload.comment.body).trim() || '';
-            const usage = 'Usage: `@TheRespectPanda ping|help`';
+            const usage = 'Usage: `@TheRespectPanda ping|help|benchmark`';
 
             if (!body.startsWith('@TheRespectPanda')) {
               return;
@@ -27,10 +28,51 @@ jobs:
               case '@TheRespectPanda ping':
                 answer = 'Pong! 🐼';
                 break;
+
               case '@TheRespectPanda':
               case '@TheRespectPanda help':
                 answer = 'Hello! I am TheRespectPanda Bot. ' + usage;
                 break;
+
+              case '@TheRespectPanda benchmark':
+                // Only runnable on pull requests
+                if (!context.payload.issue.pull_request) {
+                  answer = 'The `benchmark` command can only be used on pull requests.';
+                  break;
+                }
+
+                try {
+                  // fetch PR details
+                  const pr = await github.rest.pulls.get({
+                    owner: context.repo.owner,
+                    repo: context.repo.repo,
+                    pull_number: context.issue.number
+                  });
+
+                  // dispatch the perf workflow
+                  const repoInfo = await github.rest.repos.get({ owner: context.repo.owner, repo: context.repo.repo });
+                  const ref = repoInfo.data.default_branch || 'main';
+
+                  const workflowId = 'ci-perf.yml';
+                  const dispatchResp = await github.rest.actions.createWorkflowDispatch({
+                    owner: context.repo.owner,
+                    repo: context.repo.repo,
+                    workflow_id: workflowId,
+                    ref,
+                    inputs: {
+                      baseline: 'latest',
+                      pull: String(context.issue.number)
+                    }
+                  });
+
+                  let runUrl = dispatchResp && dispatchResp.data && dispatchResp.data.workflow_run && dispatchResp.data.workflow_run.html_url;
+                  answer = `Triggered phpbench benchmarks for PR #${context.issue.number} — workflow run: ${runUrl}`;
+                } catch (err) {
+                  answer = `Failed to trigger benchmarks: ${err.message}`;
+                }
+
+                break;
+
               default:
                 answer = "I'm sorry, I don't understand that command. " + usage;
             }