Confusing behavior with tsconfig and alias in some cases

[dummdidumm]

Describe the bug

If you import something from a folder which isn't aliased, intellisense will suggest imports which are resolvable by TypeScript but not Vite.

Reproduction

Consider this folder structure:

src
  | utils
    | x.ts
  | routes
    | index.svelte

If you import something from routes that is within utils you'll get the following suggestion: import X from "src/utils/x . Reason: The generated tsconfig.json contains "baseUrl": ".". In the eyes of TS this is a correct import path due to the base path alias, in the eyes of Vite it's not because we don't define such an alias (only $lib by default).

I'm not sure of the best solution here. Maybe we should always add an alias to Vite that resolves src/.. to real/path/to/src.

Logs

No response

System Info

System:                                                    
    OS: Windows 10 10.0.19044                                
    CPU: (12) x64 Intel(R) Core(TM) i7-9850H CPU @ 2.60GHz   
    Memory: 13.04 GB / 31.79 GB                              
  Binaries:                                                  
    Node: 16.15.1 - C:\Program Files\nodejs\node.EXE         
    npm: 8.13.2 - C:\Program Files\nodejs\npm.CMD            
  Browsers:                                                  
    Chrome: 103.0.5060.66                                    
    Edge: Spartan (44.19041.1266.0), Chromium (103.0.1264.44)
    Internet Explorer: 11.0.19041.1566                       
  npmPackages:                                               
    @sveltejs/adapter-node: 1.0.0-next.78 => 1.0.0-next.78   
    @sveltejs/kit: 1.0.0-next.357 => 1.0.0-next.357          
    svelte: 3.48.0 => 3.48.0

Severity

annoyance

Additional Information

No response

[dummdidumm]

Turns out it is possible to omit the baseUrl option (microsoft/TypeScript#31869). That would fix this bug, but unfortunately it means that the paths in paths then need to be relative (../src/lib instead of src/lib in our example for the $lib alias) - and that could be regarded as a breaking change since people could have added manual paths in their tsconfig assuming the non-relative path works. Ideally noone should be using paths in their tsconfig and instead use svelte.config.js#kit.alias but that's certainly not the case for everyone.
The linked issue provides some workarounds which I tried out and they either didn't work or sound like they cause problems with other tooling.

I guess the best option is to add a Vite path alias as mentioned in the issue.