importing in tsdown.config.ts throws: Cannot find module

[snebjorn]

I've got the following config

// tsdown.config.ts
import { defineConfig } from 'tsdown';
import { baseOptions } from '../tsdown.base';

export default defineConfig(baseOptions);

https://github.com/snebjorn/orval/blob/3ab038a5dfc5c86e20fe7fe392b527478e60c352/packages/core/tsdown.config.ts#L3

When building I get this error

$ yarn build
ℹ tsdown v0.15.2 powered by rolldown v1.0.0-beta.38

 ERROR  Error: Failed to load the config file. Try setting the --config-loader CLI flag to `unconfig`.

Cannot find module 'C:\Users\omitted\dev\orval\packages\tsdown.base' imported from C:\Users\omitted\dev\orval\packages\core\tsdown.config.ts

The imported file '../tsdown.base' is a .ts file so the correct path would be C:\Users\omitted\dev\orval\packages\tsdown.base.ts

What am I doing wrong?

[sxzz]

As error message:

Try setting the --config-loader CLI flag to `unconfig`

See https://tsdown.dev/options/config-file#config-loaders

[snebjorn]

Oh the error message just said the thing I should do 🤡

I read it as saying "Try with no config"