fix empty commit error

action.yml

@@ -27,8 +27,9 @@ inputs:
     required: false
   body:
     description: >
-      Override the default generated PR body, the special string `{old_pull_request_id}` will be substituted
-      for the ID of the pull request which triggered the action
+      Override the default generated PR body. The special string `{old_pull_request_id}` will be substituted
+      for the ID of the pull request which triggered the action, and `{old_body}` will be substituted
+      for the body of the pull request which triggered the action.
     required: false
   labels:
     description: "A comma or newline separated list of labels."

src/github-helper.ts

@@ -58,6 +58,9 @@ export async function createPullRequest(
         '{old_pull_request_id}',
         pull_request.number.toString()
       )
+      // replace {old_body} with the original PR body so callers can prepend
+      // or append text while still including the original description
+      body = body.replace('{old_body}', pull_request.body ?? '')
     }
     core.info(`Using body '${body}'`)
 

src/index.ts

@@ -75,7 +75,15 @@ export async function run(): Promise<void> {
     }
     // Take whatever is suggested by git if there are conflicts
     await gitExecution(['add', '.'])
-    await gitExecution(['commit'])
+
+    // only commit if there are changes
+    const status = await gitExecution(['status', '--porcelain'])
+    if (status.stdout.trim().length === 0) {
+      core.info('Working tree clean; skipping commit.')
+    } else {
+      await gitExecution(['commit', '--no-edit'])
+    }
+
     core.endGroup()
 
     // Push new branch