Weird error: Failed to find the GHC version of this Cabal project

[mouse07410]

Your environment

• Which OS do you use? macOS Monterey 12.5.1

• Which version of GHC do you use and how did you install it? GHC-9.4.2, installed via ghcup

• How is your project built (alternative: link to the project)? Via Cabal-3.8.1.0

• Which LSP client (editor/plugin) do you use? VS Codium+vscode-haskell

• Which version of HLS do you use and how did you install it? 1.8.0.0 via ghcup

• Which LSP client (editor/plugin) do you use? VS Code + Haskell v2.2.1

• Have you configured HLS in any way (especially: a hie.yaml file)? No hie.yaml
  In the $HOME/Library/Application Support/Code/User/settings.json:

   "haskell.hlint.executablePath": "/Users/ur20980/.cabal/bin/hlint",
    "haskell.hlint.logLevel": "info",
    "haskell.hlint.ignore": ["camelCase"],
    "haskell.trace.server": "messages",
    "haskell.updateBehavior": "prompt",
    "haskelly.exec.reuseTerminal": true,
    "haskell.plugin.ghcide-type-lenses.config.mode": "always",
    "haskell.plugin.alternateNumberFormat.globalOn": false,
    "haskell.ghcupExecutablePath": "/Users/ur20980/.ghcup/bin/ghcup",
    "[haskell]": {
        "editor.defaultFormatter": "sjurmillidahl.ormolu-vscode"
    },
    "haskell.manageHLS": "GHCup",
    "haskell.plugin.eval.config.exception": true,
    "haskell.serverEnvironment": { 
        "PATH":        "${HOME}/.ghcup/bin:${PATH}",
    },
    "haskell.serverExecutablePath": "${HOME}/.ghcup/bin/haskell-language-server-wrapper",

Steps to reproduce

Start VS Code and open project directory.

Expected behaviour

No errors.

Actual behaviour

VS Code error message popup:

Failed to find the GHC version of this Cabal project. Error when calling cabal exec -v0 -- ghc --print-libdir

Source: Haskell (Extension)

In the Terminal:

$ cabal exec -v0 -- ghc --print-libdir
/Users/ur20980/.ghcup/ghc/9.4.2/lib/ghc-9.4.2/lib
$ 

Debug information

Tried to check Troubleshooting page, did not get far with VS Code on Mac.

$ haskell-language-server-wrapper --probe-tools
haskell-language-server version: 1.8.0.0 (GHC: 9.4.2) (PATH: /Users/ur20980/.ghcup/hls/1.8.0.0/lib/haskell-language-server-1.8.0.0/bin/haskell-language-server-wrapper)
Tool versions found on the $PATH
cabal:          3.8.1.0
stack:          2.9.1
ghc:            9.4.2

Tool versions in your project
ghc:            Not found
$ ghc -V
The Glorious Glasgow Haskell Compilation System, version 9.4.2
$ 

[blamario]

I've just encountered the same issue, except with GHC 9.2.4 and in Emacs with eglot. The command reported as problematic works in shell:

$ cabal exec -v0 -- ghc --print-libdir
/home/mario/.ghcup/ghc/9.2.4/lib/ghc-9.2.4

[blamario]

$ haskell-language-server-wrapper --probe-tools
haskell-language-server version: 1.8.0.0 (GHC: 9.4.2) (PATH: /home/mario/.ghcup/hls/1.8.0.0/lib/haskell-language-server-1.8.0.0/bin/haskell-language-server-wrapper)
Tool versions found on the $PATH
cabal:          3.8.1.0
stack:          Not found
ghc:            9.2.4

Tool versions in your project
ghc:            Not found

[mouse07410]

Yes.

In my case, the problem seems related to HLS failing to get the correct PATH from the IDE(in my case- VS Code) regardless of how I set haskell.serverEnvironment. In fact, setting it seemed to make the problem worse.

[fendor]

Iirc, @mouse07410 you should remove "haskell.serverExecutablePath": "${HOME}/.ghcup/bin/haskell-language-server-wrapper" as it overrides the "manageHLS": "GHCup" setting, which is what you want.
Also, for this bug report, please provide the logs of vscode https://github.com/haskell/vscode-haskell#troubleshooting

[mouse07410]

Closing - this issue must have something to do with my config, and until I nail it, there's no point getting this team involved. Will re-open if/when find useful details to report.