External relative paths should be resolved relative to the output dir

[marijnh]

Currently (as of 1.22.0), if you have an input file src/foo/foo.js that imports "../../dep" (marked as external in the configuration), and you have rollup bundle it into dist/foo.js, the output file, that file will also reference ../../dep, though that means a different thing from its directory than it did from the source file's directory. So that file will generally fail to run.

Would it make sense to have the library re-resolve external relative paths relative to the output directory?

[lukastaegert]

Not sure about this, but I would be open to more opinions here. At the moment, you should be able to fix that manually via output.paths.

[lukastaegert]

Also note that when using the JS API, dir is not a required parameter when generating an in-memory bundle, which is also how the browser bundle works. So in such a situation, it would not be possible to resolve relative to dir.

[darionco]

output.paths is not enough in my situation:

I have an external library that needs to be imported in two files where I am using code splitting, for the sake of organization the chunks are being rendered in two different folders, my project structure looks something like this:

root/
├── src/
│   ├── moduleA/
|   |   └── ...
│   └── otherModules/
|       ├── moduleB/
|       |   └── ...
|       └── ...
└── build/
    ├── static_module/
    |   └── ...
    ├── moduleA/
    |   └── [rollup renders the moduleA chunk here]
    └── otherModules/
        ├── moduleB/
        |   └── [rollup renders the moduleB chunk here]
        └── ...

In the example above both moduleA and moduleB import static_module, if rollups build is untouched, the import paths for static_module end up being incorrect and output.paths is not enough as I only get the absolute path to the static_module but I don't know which module is importing it so it's impossible to calculate the correct path to the files.

For the time being I wrote a small plugin that hooks resolveId and returns an object like:

{
  id: [correct relative path to `static_module` after the importing file is built],
  external: true,
}

but that only works if the entry point of the chunk is importing the file, otherwise it would be impossible to compute the proper relative path to static_module from the final location of the chunk.

I think that the best solution would be to add chunkPath or similar as a second argument to output.paths when it is a function, that way users would have all the information needed to generate a proper path to external libraries.