From 19d4c1dfe344bd1bfd0344d1eb2b8f6a307a474d Mon Sep 17 00:00:00 2001
From: Jeffrey Sica <me@jeefy.dev>
Date: Wed, 7 Oct 2026 19:56:43 -0500
Subject: [PATCH] fix: treat an issue comment without a body as having no
 commands

GitHub allows an empty issue comment, whose `comment.body` arrives as
null. handleIssueComment passed it straight to hasCommand, whose line
splitting calls `body.replace(...)`, so the run failed with
`TypeError: Cannot read properties of null (reading 'replace')`.

A missing or null body is now read as the empty string: no command
matches, nothing is called and the run succeeds. The handlers only run
after hasCommand has matched, and /meow, the approve plugin and the
comment scanners already guard their bodies, so the dispatcher is the
only place the crash was reachable.

Signed-off-by: Jeffrey Sica <me@jeefy.dev>
---
 .../commentWithoutBody.test.ts                | 51 +++++++++++++++++++
 dist/index.js                                 |  3 +-
 src/issueComment/handleIssueComment.ts        |  3 +-
 3 files changed, 55 insertions(+), 2 deletions(-)
 create mode 100644 __tests__/issueCommentTest/commentWithoutBody.test.ts

diff --git a/__tests__/issueCommentTest/commentWithoutBody.test.ts b/__tests__/issueCommentTest/commentWithoutBody.test.ts
new file mode 100644
index 0000000..90f6fb8
--- /dev/null
+++ b/__tests__/issueCommentTest/commentWithoutBody.test.ts
@@ -0,0 +1,51 @@
+import * as core from '@actions/core'
+import { setupServer } from 'msw/node'
+import { afterAll, afterEach, beforeAll, beforeEach, describe, expect, it, vi } from 'vitest'
+
+import { handleIssueComment } from '../../src/issueComment/handleIssueComment'
+import issueCommentEvent from '../fixtures/issues/issueCommentEvent.json'
+import * as utils from '../testUtils'
+
+const server = setupServer()
+let calls: string[]
+beforeAll(() => server.listen(utils.failOnUnhandledRequest))
+beforeEach(() => {
+  utils.setupActionsEnv('/assign /approve /lgtm /hold /kind /help /meow /retest /check-required-labels')
+  calls = []
+  server.events.on('request:start', ({ request }) => {
+    calls.push(`${request.method} ${request.url}`)
+  })
+})
+afterEach(() => {
+  server.resetHandlers()
+  server.events.removeAllListeners()
+})
+afterAll(() => server.close())
+
+function withComment(comment: Record<string, unknown> | undefined) {
+  const payload = structuredClone(issueCommentEvent) as Record<string, unknown>
+  if (comment === undefined)
+    delete payload.comment
+  else
+    payload.comment = comment
+  return new utils.MockContext(payload)
+}
+
+const { body: _body, ...commentWithoutBody } = issueCommentEvent.comment
+
+describe('an issue comment without a body', () => {
+  it.each([
+    ['a null body', () => withComment({ ...commentWithoutBody, body: null })],
+    ['no body field', () => withComment(commentWithoutBody)],
+    ['no comment at all', () => withComment(undefined)],
+  ])('runs no command and succeeds with %s', async (_name, contextFor) => {
+    const setFailed = vi.spyOn(core, 'setFailed').mockImplementation(() => {})
+    const fetchSpy = vi.spyOn(globalThis, 'fetch')
+
+    await expect(handleIssueComment(contextFor())).resolves.toBeUndefined()
+
+    expect(setFailed).not.toHaveBeenCalled()
+    expect(fetchSpy).not.toHaveBeenCalled()
+    expect(calls).toEqual([])
+  })
+})
diff --git a/dist/index.js b/dist/index.js
index 574f8c0..3022ed8 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -46606,7 +46606,8 @@ async function handleIssueComment(context = github_context) {
             .split(/\s+/)
             .filter(command => command !== '')
             .map(command => canonicalCommand(command.toLowerCase())))];
-    const commentBody = context.payload.comment?.body;
+    // GitHub allows an empty comment, whose body arrives as null
+    const commentBody = context.payload.comment?.body ?? '';
     if (commandConfig.length === 0) {
         setFailed(`please provide a list of space delimited commands / jobs to run. None found`);
         return;
diff --git a/src/issueComment/handleIssueComment.ts b/src/issueComment/handleIssueComment.ts
index 4f55833..af0d541 100644
--- a/src/issueComment/handleIssueComment.ts
+++ b/src/issueComment/handleIssueComment.ts
@@ -113,7 +113,8 @@ export async function handleIssueComment(context: Context = github.context): Pro
       .filter(command => command !== '')
       .map(command => canonicalCommand(command.toLowerCase())),
   )]
-  const commentBody: string = context.payload.comment?.body
+  // GitHub allows an empty comment, whose body arrives as null
+  const commentBody: string = context.payload.comment?.body ?? ''
 
   if (commandConfig.length === 0) {
     core.setFailed(