same hs-source-dirs for multiple components causes confusion

[andreabedini]

I am troubleshooting haskell-language-server doing something wrong on the cabal repository. If I do:

$ haskell-language-server-wrapper cabal-install/tests/IntegrationTests2.hs
...
File:     /home/andrea/code/cabal/cabal-install/tests/IntegrationTests2.hs
Hidden:   no
Range:    77:8-77:19
Source:   not found
Severity: DsError
Message: 
  Could not load module ‘Data.Tagged’
  It is a member of the hidden package ‘tagged-0.8.7’.
  Perhaps you need to add ‘tagged’ to the build-depends in your .cabal file.

which is wrong because IntegrationTests2 is part of the test-suite integration-tests2 which has indeed tagged among its build-depens.

test-suite integration-tests2
  import: warnings, base-dep, cabal-dep, cabal-syntax-dep, cabal-install-solver-dep
  ghc-options: -rtsopts -threaded
  type: exitcode-stdio-1.0
  main-is: IntegrationTests2.hs
  hs-source-dirs: tests
  default-language: Haskell2010

  build-depends:
        bytestring,
        cabal-install,
        containers,
        directory,
        filepath,
        tasty >= 1.2.3 && <1.5,
        tasty-hunit >= 0.10,
        tagged

to confirm I can do

cabal repl cabal-install/tests/IntegrationTests2.hs

which works ok.

I suspect that this happens because multiple components hs-source-dirs: tests and indeed adding --debug to hls shows

2023-05-25T03:26:53.728418Z | Debug | executing command: cabal --builddir=/home/andrea/.cache/hie-bios/dist-cabal-2d99de0514754dc7a0fdd74187917280 v2-repl --with-compiler /home/andrea/.cache/hie-bios/wrapper-b54f81dea4c0e6d1626911c526bc4e36 --with-hc-pkg /home/andrea/.cache/hie-bios/ghc-pkg-5fcb2ba7874e41991c2aef3124b07071 cabal-install:test:unit-tests

which is indeed the wrong component.

I checked directly with hie-bios (version 0.12.0) and it gets the component right

$ hie-bios flags cabal-install/tests/IntegrationTests2.hs
...
[Debug] executing command: cabal --builddir=/home/andrea/.cache/hie-bios/dist-cabal-2d99de0514754dc7a0fdd74187917280 v2-repl --with-compiler /home/andrea/.cache/hie-bios/wrapper-b54f81dea4c0e6d1626911c526bc4e36 --with-hc-pkg /home/andrea/.cache/hie-bios/ghc-pkg-5fcb2ba7874e41991c2aef3124b07071 cabal-install/tests/IntegrationTests2.hs
[Debug] Build profile: -w ghc-9.4.5 -O1
[Debug] In order, the following will be built (use -v for more details):
[Debug]  - cabal-install-3.11.0.0 (test:integration-tests2) (first run)
[Debug] Configuring test suite 'integration-tests2' for cabal-install-3.11.0.0..
...

Your environment

Which OS do you use? Linux
Which version of GHC do you use and how did you install it? 9.4.5, via ghcup
How is your project built (alternative: link to the project)? https://github.com/haskell/cabal/
Which LSP client (editor/plugin) do you use? N/A
Which version of HLS do you use and how did you install it? 2.0.0.0 from ghcup
Have you configured HLS in any way (especially: a hie.yaml file)? No

[fendor]

Thank you for the bug report! This is a bug in implicit-hie.

You can work around it by adding an explicit hie.yaml:

cradle:
  cabal:

I can confirm from my personal experience on cabal, that this works much better.

[andreabedini]

Thanks @fendor, your workaround does the trick! I did endup using a hie.yaml file but I didn't realise a simple one like that would be enough!

Edit: indeed this is what implict-hie spits out

cradle:
  cabal:
...
    - path: "cabal-install/tests"
      component: "cabal-install:test:unit-tests"

    - path: "cabal-install/tests"
      component: "cabal-install:test:mem-use-tests"

    - path: "cabal-install/tests"
      component: "cabal-install:test:integration-tests2"

    - path: "cabal-install/tests"
      component: "cabal-install:test:long-tests"
...

[fendor]

I did endup using a hie.yaml file but I didn't realise a simple one like that would be enough!

The simple cabal cradle uses cabal repl <file>, and cabal almost always figures it out correctly. There is rarely a situation where it doesn't, that's why the simple cradle is virtually always the best choice, imo.

[michaelpj]

Should be fixed now we're not using implicit-hie