Problem with generic type with custom-fetch

[camillecroci]

What are the steps to reproduce this issue?

1. Create a custom fetch similar to the example in next-app-with-fetch sample
2. Generates code, or look at the generated code from the sample

export const listPets = async (
  params?: ListPetsParams,
  options?: RequestInit,
): Promise<listPetsResponse> => {
  return customFetch<Promise<listPetsResponse>>(getListPetsUrl(params), {
    ...options,
    method: 'GET',
  });
};

3. Look at the type passed for the customFetch in the generated code. If you have vscode, you can hover on your generated function to see the return type of it.

What happens?

Custom-fetch receives a Promise<listPetsResponse> in place of the generic T.

What were you expecting to happen?

Only to pass listPetsResponse in place of the generic T. Custom-fetch has to await so its expected signature will be Promise<T>. If you pass Promise<listPetsResponse>, you end up with functions that have returned type Promise<Promise>`

Any logs, error output, etc?

No errors, I think it is just incorrect in term of type.

What versions are you using?

  System:
    OS: macOS 15.1.1
    CPU: (8) arm64 Apple M1
    Memory: 76.56 MB / 16.00 GB
    Shell: 3.2.57 - /bin/bash
  npmPackages:
    msw: ^2.6.5 => 2.6.5 
    orval: ^7.1.1 => 7.1.1