"cabal-hls-install ghcs" does not list all ghc versions available.

[dcastro]

I have ghc 8.10.4 installed (through ghcup). However, when I run ./cabal-hls-install ghcs, version 8.10.4 does not show up.

Your environment

$ ghc --version
The Glorious Glasgow Haskell Compilation System, version 8.10.4

$ where ghc
/home/dc/.ghcup/bin/ghc
/usr/bin/ghc
/bin/ghc

Ubuntu 20.04.3 LTS.

Steps to reproduce

1. Checked out the latest master (1119def0f94598086f5c8b23c727a40f99cdd969)
2. Run ./cabal-hls-install ghcs.

Expected behaviour

I expected GHC 8.10.4 to be listed.

Actual behaviour

$ ./cabal-hls-install ghcs

********************************************************************************
Found the following GHC paths: 
ghc-8.6.5: /usr/bin/ghc-8.6.5
ghc-8.8.3: /home/dc/.ghcup/bin/ghc-8.8.3
ghc-8.8.4: /home/dc/.ghcup/bin/ghc-8.8.4

********************************************************************************

Build completed in 0.00s

[jneira]

I am afraid that we dropped support for ghc-8.10.4 so we removed stack-8.10.4.yaml and it is the source for the supported ghcs list in the script. cabal-hls-install ghcs lists the supported ghcs in path so 8.10.4 is not shown.

The message has to be improved as it should note Found the following supported GHC paths:.

Possible solutions:

• create a dummy stack-8.10.4.yaml, it could be empty if you are not gonna use stack. If you want install with stack, copying it from another 8.10.* and change the resolver might work (maybe with some deps tweaks)
• if you are not using a custom version of hls, it can be installed from source using ghcup: ghcup compile hls -v 1.4.0 8.10.4
• upgrade your ghc to a hls supported version 8.10.5, 8.10.6 or 8.10.7 (recommended)

[dcastro]

Ah that makes sense, thanks @jneira !

I was indeed trying to install a custom version of hls (compiled with -dynamic in order to fix the issue described in #230 and #469), so I just upgraded to ghc 8.10.7.

[dcastro]

Feel free to close the issue if you see fit.

[jneira]

I was indeed trying to install a custom version of hls (compiled with -dynamic in order to fix the issue described in #230 and #469), so I just upgraded to ghc 8.10.7.

It is possible with ghcup:

• create a cabal.project.dyn with

package haskell-language-server
  ghc-options: -dynamic

• run ghcup compile hls --cabal-project-local=cabal.project.dyn -v 1.4.0 ${ghcVersion}
• disclaimer: i've no tested it

There is even an issue about automate it: https://gitlab.haskell.org/haskell/ghcup-hs/-/issues/245

[jneira]

Feel free to close the issue if you see fit.

#2285 will do, thanks for report the issue!

[dcastro]

Thanks @jneira, ghcup compile worked!

Just wanted to point out to future readers that the correct syntax for the --cabal-project-local option is to use a file:// scheme, and that the command is missing a --ghc option.

ghcup compile hls --cabal-project-local="file://${fullPath}>/cabal.project.dyn" -v 1.4.0 --ghc ${ghcVersion}