Goto definition of local library seems not working until I load the library once. about haskell-language-server

[Anrock]

IMO eagerly loading everything sounds like a desirable behaviour. IDE that works only for some symbols or shows only some diagnostics depending on what files user have touched before sounds pretty flawed to me. Perhaps HLS could index other files in low-priority background thread? Or maybe not all files but all current file imports and reverse imports?

[BurningLutz]

Thanks for all your replies! The workaround @fendor provided works great!

As @fendor and @michaelpj pointed, this is currently by design and there is #3873 tracking this problem, I'm going to close this now.

[BurningLutz]

more information, If the new project is created inside a directory that is already indexed by HLS, the goto-definiation seems to work even I didn't open the MyLib.hs file once.

[fendor]

Hi, thank you for your bug report!

This is expected behaviour, we do not have a notion to eagerly load components directly. We still load components lazily, e.g. only when you actually open them.
The reason it works on subsequent start is, we have a sqlite database (hiedb) which caches the relevant information (e.g. definitions), so it works once it has been indexed.

There is one work-around, tell cabal to load all components with this hie.yaml:

cradle:
  cabal:
    component: all

If tests and benchmarks are enabled in your cabal.project, this is equivalent to a fully eager load of the project.

[michaelpj]

See #3873.

I do agree that it would be great if we at least indexed everything. However I think at the moment that requires loading everything into our session, which is a big, global choice. So I don't know that we can easily do this in the background.

I think probably what we would ideally do is get cabal to build the components out-of-process and get it to write the HIE files, which should then let us index things?