hls does not detect new dependencies added to packages.yml

[GuillaumeDesforges]

Bug description

I'm using VS Code, with the ghcide extension.

When adding a package dependency to the package.yaml, I have to reload to entire VS Code window to restart ghcide to detect and load this new dependency in ghcide.

Desired behaviour

ghcide should reload the dependencies when packages.yaml is updated, so that I don't have to restart it manually.

Version

$ ghcide --version
ghcide version: 0.2.0 (GHC: 8.8.3) (PATH: /nix/store/sdn0dabqvc1g25s8grq7sa9g13ax8fk7-ghcide-exe-ghcide-0.2.0/bin/ghcide)

using Remote SSH extension for VS Code

vscode client on Windows 10
vscode server on NixOS 20.03

I use the ghcide-nix derivation to get GHCIDE (version was recently bumped there)

[ndmitchell]

You can do "Restart extension host" to reload just the extensions, which is a bit less violent. Agreed that auto-reloading the right pieces would be desirable - I guess this is a package.yaml file that Stack transforms into a mypackage.cabal file?

[fendor]

I think that the stack cradle is watching for changes to package.yaml and should detect these changes.

[GuillaumeDesforges]

I think that the stack cradle is watching for changes to package.yaml and should detect these changes.

That was my understanding as well, but it doesn't.

[fendor]

Is the project structure different to a basic stack new? Or haskeleton template?

[GuillaumeDesforges]

It is a stack project with multiple projects (in subdirectories), and one of the project is a classic component defined by a package.yaml

The hie.yaml defines multiple cradles for the projects, and the concerned cradle has a standard config (stack component)

[fendor]

Maybe that is the problem, the dependencies ought to be relative to the cradleRootDir. Maybe they are not canonicalized in ghcide?
https://github.com/digital-asset/ghcide/blob/master/exe/Main.hs#L271
Should probably make the filepaths relative to the cradleRootDir or make them even absolute.

[fendor]

We actually need both, the dependencies could be relative to the cradleRootDir or to componentRootDir e.g.

.
├── cabal.project
├── servant-server
│   └── servant-server.cabal
└─── servant-docs
    └── servant-docs.cabal

Options for 'servant-server'
Root directory:      ./servant
Component directory: ./servant/servant-server
Dependencies:        stack.yaml servant-server.cabal package.yaml

Options for 'servant-docs'
Root directory:      ./servant
Component directory: ./servant/servant-docs
Dependencies:        stack.yaml servant-docs.cabal package.yaml

We need to reload both components in case of change to ./servant/stack.yaml but only one for changes to ./servant/servant-server/servant-server.cabal, ./servant/servant-server/package.yaml and ./servant/servant-docs/servant-docs.cabal, ./servant/servant-docs/package.yaml respectively.

A proposed solution:
Change the API of cradle dependencies in hie-bios to give absolute paths since this is the only location where we can know this. (Another breaking change, yay)
Unfortunately, this does not play nicely with the latest breaking change to extend a CradleError with the dependencies of the component, since we dont know the component dir in that case :(

[pepeiborra]

@fendor can this ticket be closed now?