[CI] Add help command to rerun workflow bot

- Enhance rerun workflow bot to support `/rerun help` command.
- Provide detailed documentation for rerun commands in response to `/rerun help`.
- Ensure all rerun workflow steps are skipped when the help command is invoked.

Author: mikepapadim

.github/workflows/rerun-workflow.yml

@@ -18,7 +18,36 @@ jobs:
       contents: read
 
     steps:
+      - name: Check for help command
+        id: help
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const comment = context.payload.comment.body;
+            if (comment.match(/\/rerun\s+help/i)) {
+              await github.rest.issues.createComment({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                issue_number: context.issue.number,
+                body: `## 🔄 Rerun Workflow Commands
+  
+              | Command | Description |
+              |---------|-------------|
+              | \`/rerun\` | Rerun only **failed/cancelled/timed-out** workflows |
+              | \`/rerun all\` | Rerun **all** workflows for this PR |
+              | \`/rerun failed\` | Same as \`/rerun\` |
+              | \`/rerun <name>\` | Rerun workflows matching \`<name>\` (e.g. \`/rerun ci\`, \`/rerun build\`) |
+              | \`/rerun help\` | Show this help message |
+              
+              **Note:** Only completed workflows can be rerun. In-progress workflows are skipped.`
+              });
+              core.setOutput('is_help', 'true');
+              } else {
+              core.setOutput('is_help', 'false');
+              }
+
       - name: Get PR SHA
+        if: steps.help.outputs.is_help != 'true'
         id: pr
         uses: actions/github-script@v7
         with:
@@ -34,6 +63,7 @@ jobs:
             console.log(`PR head ref: ${pr.head.ref}`);
 
       - name: Add reaction to comment
+        if: steps.help.outputs.is_help != 'true'
         uses: actions/github-script@v7
         with:
           script: |
@@ -45,6 +75,7 @@ jobs:
             });
 
       - name: Post start comment
+        if: steps.help.outputs.is_help != 'true'
         uses: actions/github-script@v7
         with:
           script: |
@@ -60,6 +91,7 @@ jobs:
             });
 
       - name: Rerun failed workflows
+        if: steps.help.outputs.is_help != 'true'
         uses: actions/github-script@v7
         with:
           script: |
@@ -96,21 +128,21 @@ jobs:
                 rerunArg === 'all' ||
                 (rerunArg === 'failed' && ['failure', 'cancelled', 'timed_out'].includes(run.conclusion)) ||
                 run.name.toLowerCase().includes(rerunArg);
-              
+            
               if (!shouldRerun) {
                 console.log(`Skipping ${run.name} (status: ${run.status}, conclusion: ${run.conclusion})`);
                 continue;
               }
-              
+            
               // Only rerun completed workflows
               if (run.status !== 'completed') {
                 console.log(`Skipping ${run.name} - still ${run.status}`);
                 continue;
               }
-              
+            
               try {
                 console.log(`Rerunning workflow: ${run.name} (ID: ${run.id})`);
-                
+            
                 // Use rerun-failed-jobs if available and workflow failed, otherwise full rerun
                 if (['failure', 'cancelled', 'timed_out'].includes(run.conclusion)) {
                   await github.rest.actions.reRunWorkflowFailedJobs({
@@ -134,7 +166,7 @@ jobs:
             console.log(`Reran ${rerunCount} workflow(s)`);
 
       - name: Post completion comment
-        if: always()
+        if: always() && steps.help.outputs.is_help != 'true'
         uses: actions/github-script@v7
         with:
           script: |
@@ -146,4 +178,4 @@ jobs:
               repo: context.repo.repo,
               issue_number: context.issue.number,
               body: `${emoji} **Workflow rerun ${status}**\n\n[View Actions](https://github.com/${context.repo.owner}/${context.repo.repo}/actions)`
-            });
+            });