Unexpected end of creating new project if no pnpm installed

[bruha]

Version

4.4.1

Environment info

System:
    OS: macOS 10.15.5
    CPU: (12) x64 Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
  Binaries:
    Node: 13.11.0 - ~/.nvm/versions/node/v13.11.0/bin/node
    Yarn: 1.22.4 - /usr/local/bin/yarn
    npm: 6.14.5 - ~/.nvm/versions/node/v13.11.0/bin/npm
  Browsers:
    Chrome: 83.0.4103.61
    Edge: Not Found
    Firefox: Not Found
    Safari: 13.1.1
  npmGlobalPackages:
    @vue/cli: 4.4.1

Steps to reproduce

1. Run vue ui on a machine without pnpm installed
2. Create new project with pnpm as a package manager
3. Observe an error

What is expected?

Warning that I should install pnpm or offer to install it automatically

What is actually happening?

vue ui
🚀  Starting GUI...
🌠  Ready on http://localhost:8000
 ERROR  command failed: pnpm install --loglevel error --shamefully-flatten
Error: Command failed: vue create vue-playground --skipGetStarted --packageManager pnpm --inlinePreset {"useConfigFiles":false,"plugins":{"@vue/cli-plugin-babel":{},"@vue/cli-plugin-typescript":{"classComponent":true,"useTsWithBabel":true},"@vue/cli-plugin-pwa":{},"@vue/cli-plugin-eslint":{"config":"standard","lintOn":["save"]}},"cssPreprocessor":"node-sass"}
✨  Creating project in /Users/user1/vue-playground.
🗃  Initializing git repository...
⚙️  Installing CLI plugins. This might take a while...


    at makeError (/Users/user1/.nvm/versions/node/v13.11.0/lib/node_modules/@vue/cli/node_modules/execa/index.js:174:9)
    at /Users/user1/.nvm/versions/node/v13.11.0/lib/node_modules/@vue/cli/node_modules/execa/index.js:278:16
    at processTicksAndRejections (internal/process/task_queues.js:97:5)
    at async /Users/user1/.nvm/versions/node/v13.11.0/lib/node_modules/@vue/cli/node_modules/@vue/cli-ui/apollo-server/connectors/projects.js:345:5
    at async Object.wrap (/Users/user1/.nvm/versions/node/v13.11.0/lib/node_modules/@vue/cli/node_modules/@vue/cli-ui/apollo-server/connectors/progress.js:39:14) {
  code: 1,
  stdout: '✨  Creating project in /Users/user1/vue-playground.\n'  
    '🗃  Initializing git repository...\n'  
    '⚙️  Installing CLI plugins. This might take a while...\n'  
    '\n',
  stderr: null,
  failed: true,
  signal: null,
  cmd: 'vue create vue-playground --skipGetStarted --packageManager pnpm --inlinePreset {"useConfigFiles":false,"plugins":{"@vue/cli-plugin-babel":{},"@vue/cli-plugin-typescript":{"classComponent":true,"useTsWithBabel":true},"@vue/cli-plugin-pwa":{},"@vue/cli-plugin-eslint":{"config":"standard","lintOn":["save"]}},"cssPreprocessor":"node-sass"}',
  timedOut: false,
  killed: false
}