pnpm's `package.json5` file not supported

[mintydev789]

Which project does this relate to?

Start

Describe the bug

The pnpm run dev command fails when using a package.json5 file instead of package.json.

Your Example Website or App

This simply refers to the start project when initializing with the CLI

Steps to Reproduce the Bug or Issue

1. Initialize new project using the CLI with PNPM: pnpm dlx @tanstack/cli@latest create.
2. Change the package.json file to a package.json5 file (supported by PNPM).
3. Run pnpm run dev.

Expected behavior

Expected that this would work, and the error message was super cryptic, seemingly because the code just assumed that there's a file named exactly package.json.

Screenshots or Videos

No response

Platform

Not relevant to this issue

Additional context

No response

[schiller-manuel]

Change the package.json file to a package.json5 file (supported by PNPM).

so just rename the file extension?

which errors do you get?

[mintydev789]

Change the package.json file to a package.json5 file (supported by PNPM).

so just rename the file extension?

which errors do you get?

It's a very long and cryptic message that I doubt would help. You can see it with the starter example. I mean, I can rename the file, but that extension is used for JSON5-formatted files. If TanStack Start is meant to work with PNPM, ut shouldnt break just because of that file being in the other format.

[schiller-manuel]

no i meant "you just renamed the file extension to get the error"? wasnt meant as a solution. just want to know how to reproduce

also sharing a complete example repo is always good for us to make it easier to reproduce

[mintydev789]

no i meant "you just renamed the file extension to get the error"? wasnt meant as a solution. just want to know how to reproduce

also sharing a complete example repo is always good for us to make it easier to reproduce

Ah, my bad, I misunderstood. I renamed the file and formatted it as JSON5:

{
  name: 'temp',
  private: true,
  type: 'module',
  imports: {
    '#/*': './src/*'
  },
  scripts: {
    dev: 'vite dev --port 3000',
    build: 'vite build',
    preview: 'vite preview',
    test: 'vitest run',
    format: 'biome format',
    lint: 'biome lint',
    check: 'biome check'
  },
  dependencies: {
    '@tailwindcss/vite': '^4.1.18',
    '@tanstack/react-devtools': 'latest',
    '@tanstack/react-router': 'latest',
    '@tanstack/react-router-devtools': 'latest',
    '@tanstack/react-router-ssr-query': 'latest',
    '@tanstack/react-start': 'latest',
    '@tanstack/router-plugin': '^1.132.0',
    'lucide-react': '^0.545.0',
    react: '^19.2.0',
    'react-dom': '^19.2.0',
    tailwindcss: '^4.1.18'
  },
  devDependencies: {
    '@biomejs/biome': '2.4.5',
    '@tailwindcss/typography': '^0.5.16',
    '@tanstack/devtools-vite': 'latest',
    '@testing-library/dom': '^10.4.1',
    '@testing-library/react': '^16.3.0',
    '@types/node': '^22.10.2',
    '@types/react': '^19.2.0',
    '@types/react-dom': '^19.2.0',
    '@vitejs/plugin-react': '^5.1.4',
    jsdom: '^28.1.0',
    typescript: '^5.7.2',
    vite: '^7.3.1',
    'vite-tsconfig-paths': '^5.1.4',
    vitest: '^3.0.5'
  },
  pnpm: {
    onlyBuiltDependencies: [
      'esbuild',
      'lightningcss'
    ]
  }
}