not-found.tsx will appear with two duplicate robots tags

[GreedyWhale]

Link to the code that reproduces this issue

https://github.com/GreedyWhale/nextjs-meta-bug

To Reproduce

1. npx create-next-app@latest

√ What is your project named? ... my-app
√ Would you like to use TypeScript? ... No / Yes
√ Would you like to use ESLint? ... No / Yes
√ Would you like to use Tailwind CSS? ... No / Yes
√ Would you like your code inside a src/ directory? ... No / Yes
√ Would you like to use App Router? (recommended) ... No / Yes
√ Would you like to use Turbopack for next dev? ... No / Yes
√ Would you like to customize the import alias (@/* by default)? ... No / Yes

2. create not-found.tsx file

import type { Metadata } from "next"

export const metadata: Metadata = {
  title: 'My Blog',
  description: '...',
  robots: {
    index: false,
    follow: false
  }
}

export default function NotFound() {
  return (
    <div>
      <div>
        <h2>Not Found</h2>
        <p>Could not find requested resource</p>
      </div>
    </div>
  )
}

3. pnpm run dev
4. Visit http://localhost:3000/xxxx
5. Open your browser's debugging tool to view the html code

Current vs. Expected behavior

Hopefully there is only one <meta=“robots”> tag

Provide environment information

- package.json

{
  "name": "my-app",
  "version": "0.1.0",
  "private": true,
  "scripts": {
    "dev": "next dev --turbopack",
    "build": "next build",
    "start": "next start",
    "lint": "next lint"
  },
  "dependencies": {
    "react": "^19.0.0",
    "react-dom": "^19.0.0",
    "next": "15.1.8"
  },
  "devDependencies": {
    "typescript": "^5",
    "@types/node": "^20",
    "@types/react": "^19",
    "@types/react-dom": "^19",
    "postcss": "^8",
    "tailwindcss": "^3.4.1",
    "eslint": "^9",
    "eslint-config-next": "15.1.8",
    "@eslint/eslintrc": "^3"
  },
  "packageManager": "pnpm@10.5.2+sha256.79a98daa90248b50815e31460790f118c56fe099113370826caa0153be6daba5"
}

Which area(s) are affected? (Select all that apply)

Not sure

Which stage(s) are affected? (Select all that apply)

next dev (local)

Additional context

No response

[KindArt]

NextJS automatically injects the meta tag for 404 pages to prevent them from being indexed.

The notFound function allows you to render the [not-found file](https://nextjs.org/docs/app/api-reference/file-conventions/not-found) within a route segment as well as inject a <meta name="robots" content="noindex" /> tag.

As you've created your own metadata implementation within the not-found.tsx, it's now duplicated.

It won't be duplicated if you remove the robots segment from your metadata implementation:

robots: {
    index: false,
    follow: false
  }

[GreedyWhale]

NextJS会自动为 404 页面注入元标记，以防止它们被编入索引。

The notFound function allows you to render the [not-found file](https://nextjs.org/docs/app/api-reference/file-conventions/not-found) within a route segment as well as inject a <meta name="robots" content="noindex" /> tag.

由于您已经在 中创建了自己的元数据实现not-found.tsx，因此它现在已经重复。

如果您从元数据实施中删除 robots 段，它将不会重复：

robots: {
    index: false,
    follow: false
  }

Thank you, I saw this on the docs but our SEO colleague asked for nofollow and I don't know how to say no, so is this a feature of Next.js and not a bug?