Changes to `compilerOptions` in `tsconfig.json` don't get picked up by subsequent `yarn build` runs

[jaclarke]

Verify canary release

• [X] I verified that the issue exists in Next.js canary release

Provide environment information

Operating System:
  Platform: linux
  Arch: x64
  Version: #1 SMP Wed Feb 19 06:37:35 UTC 2020
Binaries:
  Node: 16.13.1
  npm: 8.1.2
  Yarn: 1.22.18
  pnpm: 6.11.0
Relevant packages:
  next: 12.1.7-canary.0
  react: 18.1.0
  react-dom: 18.1.0

What browser are you using? (if relevant)

No response

How are you deploying your application? (if relevant)

No response

Describe the Bug

Changes to compilerOptions in tsconfig.json don't get picked up by subsequent runs of yarn build, unless .next/cache/.tsbuildinfo is deleted after the changes.

Expected Behavior

Changes to tsconfig.json should be detected and subsequent yarn build runs should use the updated config.

To Reproduce

1. Create new next.js app with typescript:

   yarn create next-app --typescript
   

2. cd into project directory and update version to next@canary:

   cd my-app
   yarn add next@canary
   

3. Use some typescript feature that needs enabling by a compiler option, eg. Update pages/api/hello.ts to use iterator spreading, which requires downlevelIteration option:

   // Next.js API route support: https://nextjs.org/docs/api-routes/introduction
   import type { NextApiRequest, NextApiResponse } from "next";
   
   type Data = {
     name: string;
     numbers: number[];
   };
   
   const numbers = new Set([1, 2, 3]);
   
   export default function handler(
     req: NextApiRequest,
     res: NextApiResponse<Data>
   ) {
     res.status(200).json({ name: "John Doe", numbers: [...numbers] });
   }
   

4. Run yarn build. As expected this fails:

   $ yarn build
   
   yarn run v1.22.18
   $ next build
   Failed to compile.
   
   ./pages/api/hello.ts:15:57
   Type error: Type 'Set<number>' is not an array type or a string type. Use compiler option '--downlevelIteration' to allow    iterating of iterators.
   
     13 |   res: NextApiResponse<Data>
     14 | ) {
   > 15 |   res.status(200).json({ name: "John Doe", numbers: [...numbers] });
        |                                                         ^
     16 | }
     17 | 
   error Command failed with exit code 1.
   

5. Add "downlevelIteration": true to compilerOptions in tsconfig.json, and re-run yarn build. This fails with the same error as above.

6. Delete the .tsbuildinfo file:

   rm .next/cache/.tsbuildinfo
   

7. Re-run yarn build. This time it runs successfully.

[McKean]

@jaclarke can you try adding the following to your tsconfig?

"compilerOptions": {
   "target": "es5",
   "experimentalDecorators": true,
   "downlevelIteration": true,
}

This worked well for me

[github-actions[bot]]

Please verify that your issue can be recreated with next@canary.

Why was this issue marked with the please verify canary label?

We noticed the provided reproduction was using an older version of Next.js, instead of canary.

The canary version of Next.js ships daily and includes all features and fixes that have not been released to the stable version yet. You can think of canary as a public beta. Some issues may already be fixed in the canary version, so please verify that your issue reproduces by running npm install next@canary and test it in your project, using your reproduction steps.

If the issue does not reproduce with the canary version, then it has already been fixed and this issue can be closed.

How can I quickly verify if my issue has been fixed in canary?

The safest way is to install next@canary in your project and test it, but you can also search through closed Next.js issues for duplicates or check the Next.js releases. You can also use the GitHub template (preferred), or the CodeSandbox or StackBlitz templates to create a reproduction with canary from scratch.

My issue has been open for a long time, why do I need to verify canary now?

Next.js does not backport bug fixes to older versions of Next.js. Instead, we are trying to introduce only a minimal amount of breaking changes between major releases.

What happens if I don't verify against the canary version of Next.js?

An issue with the please verify canary that receives no meaningful activity (e.g. new comments that acknowledge verification against canary) will be automatically closed and locked after 30 days.

If your issue has not been resolved in that time and it has been closed/locked, please open a new issue, with the required reproduction, using next@canary.

I did not open this issue, but it is relevant to me, what can I do to help?

Anyone experiencing the same issue is welcome to provide a minimal reproduction following the above steps. Furthermore, you can upvote the issue using the :+1: reaction on the topmost comment (please do not comment "I have the same issue" without repro steps). Then, we can sort issues by votes to prioritize.

I think my reproduction is good enough, why aren't you looking into it quicker?

We look into every Next.js issue and constantly monitor open issues for new comments.

However, sometimes we might miss one or two due to the popularity/high traffic of the repository. We apologize, and kindly ask you to refrain from tagging core maintainers, as that will usually not result in increased priority.

Upvoting issues to show your interest will help us prioritize and address them as quickly as possible. That said, every issue is important to us, and if an issue gets closed by accident, we encourage you to open a new one linking to the old issue and we will look into it.

Useful Resources

• How to Contribute to Open Source (Next.js)
• How to create a Minimal, Complete, and Verifiable example
• Reporting a Next.js bug
• Next.js Triaging issues

[balazsorban44]

This issue has been automatically closed because it wasn't verified against next@canary. If you think it was closed by accident, please leave a comment. If you are running into a similar issue, please open a new issue with a reproduction. Thank you.

[github-actions[bot]]

This closed issue has been automatically locked because it had no new activity for a month. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.