Adding "paths" and "baseUrl" to tsconfig.json breaks module augmentations

[nexxeln]

Question 💬

We just had this issue in create-t3-app,It seems like the declared next-auth.d.ts is overriding the initial next-auth types instead of augmenting them.

We even tried declaring the the types from next-auth/core/types but doesn't seem to work still.

Note that this problem only occurs when we use path aliases.

How to reproduce ☕️

To Reproduce
Steps to reproduce the behavior:

1. npx create-t3-app@next
2. Select all packages
3. Set up path aliases like so
4. See src/pages/api/auth/[...nextauth].ts file

Contributing 🙌🏽

Yes, I am willing to help answer this question in a PR

[nexxeln]

Update: Apparently moving the next-auth.d.ts file to a subfolder fixes it.

Is there a better solution?

[balazsorban44]

AFAIK, TypeScript does not concern itself where you declare a Module Augmentation in your project, as long as the file is included in your tsconfig's includes array.

UPDATE:
Well, maybe it does, since you are setting basePath: "./" so you basically tell TS to resolve next-auth to the .d.ts file instead. 🤔

[riolly]

Update: Apparently moving the next-auth.d.ts file to a subfolder fixes it.

Is there a better solution?

Yeah, I do the same thing. Is there any better solution?