Breaking API change in types from 12.0.4 to 12.0.5

[bryanjswift]

What version of Next.js are you using?

12.0.5

What version of Node.js are you using?

14.18.1

What browser are you using?

Not applicable

What operating system are you using?

macOS

How are you deploying your application?

using custom server

Describe the Bug

The update from 12.0.4 to 12.0.5 including a breaking API change when calling the createServer function.

In 12.0.4 with TypeScript this compiles fine:

const app = next({
  dir: './src',
  dev: process.env.NODE_ENV !== 'production',
  conf: {
    compress: false,
  } as NextServerOptions['conf'],
  quiet: false,
});
const requestHandler = app.getRequestHandler();

In version 12.0.5 the above generates the following TypeError:

src/index.ts:9:3 - error TS2322: Type '{ compress: false; }' is not assignable to type 'NextConfigComplete'.
  Type '{ compress: false; }' is missing the following properties from type 'Required<NextConfig>': i18n, eslint, typescr
ipt, headers, and 33 more.

9   conf: {
    ~~~~

  ../../node_modules/next/dist/server/next-server.d.ts:34:5
    34     conf: NextConfigComplete;
           ~~~~
    The expected type comes from property 'conf' which is declared here on type 'Partial<Options>'


Found 1 error.

Expected Behavior

Existing createServer configuration would continue to work in patch versions, especially when the release notes say "This upgrade is completely backward-compatible and recommended for all users on versions below 12.0.5. A backport of the patch to Next.js 11 will be available later today."

To Reproduce

1. npx create-next-app@latest --typescript

2. Change version of next and eslint-config-next in generated package.json to 12.0.4

3. Run yarn to get the downgraded version

4. Create server.ts with following contents

    import next from 'next';
    const app = next({
      dir: '.',
      dev: process.env.NODE_ENV !== 'production',
      conf: {
        compress: false,
      },
      quiet: false,
    });
    const requestHandler = app.getRequestHandler();
   

5. Execute yarn run tsc to check types, there should be no type errors

6. Change version of next and eslint-config-next in generated package.json to 12.0.5

7. Run yarn to get the version 12.0.5

8. Execute yarn run tsc to check types, receiving the following error

    server.ts:5:3 - error TS2322: Type '{ compress: false; }' is not assignable to type 'NextConfigComplete'.
      Type '{ compress: false; }' is missing the following properties from type 'Required<NextConfig>': i18n, eslint, typescript, headers, and 33 more.
    
    5   conf: {
        ~~~~
    
      node_modules/next/dist/server/next-server.d.ts:34:5
        34     conf: NextConfigComplete;
               ~~~~
        The expected type comes from property 'conf' which is declared here on type 'Partial<Options>'
    
    
    Found 1 error.
    
    error Command failed with exit code 2.
   

[ijjk]

Hi, this has been updated in v12.0.7 of Next.js, please update and give it a try!

[bryanjswift]

Hi, this has been updated in v12.0.7 of Next.js, please update and give it a try!

Thanks for the quick fix!

[balazsorban44]

This issue has been automatically locked due to no recent activity. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.