subtle component caching issue when there is a symlink in the path of the repo

[maralorn]

Your environment

Which OS do you use: Nixos
Which LSP client (editor/plugin) do you use: VSCodium/coc-nvim
Describe your project (alternative: link to the project): various, e.g. https://github.com/maralorn/nix-output-monitor

Steps to reproduce

My ~/git folder is a symlink (onto another filesystem).

I run haskell-language-server -d in ~/git/nix-output-monitor I get this log: https://termbin.com/pkk4
When I copy the project to ~/nix-output-monitor I get the expected behavior.
When I manually resolve the symlink and run hls in /disk/persist/git/nix-output-monitor I get the expected behavior.

Expected behaviour

hls should load the project normally, which means loading the library component once, when it encounters a file from the library.

Actual behaviour

hls loads the component/cradle new for every file in the library. Crucially files first get listed in
2022-03-26 12:51:30.50850162 [ThreadId 113] DEBUG hls: Known files updated:
but then shortly after a new cradle get’s created for a supposedly known file:

2022-03-26 12:51:30.60907107 [ThreadId 399] INFO hls:	Consulting the cradle for "lib/NOM/State/Sorting.hs"
2022-03-26 12:51:30.60915896 [ThreadId 399] WARNING hls:	No [cradle](https://github.com/mpickering/hie-bios#hie-bios) found for lib/NOM/State/Sorting.hs.
 Proceeding with [implicit cradle](https://hackage.haskell.org/package/implicit-hie).
You should ignore this message, unless you see a 'Multi Cradle: No prefixes matched' error.
2022-03-26 12:51:30.611110962 [ThreadId 399] DEBUG hls:	Output from setting up the cradle Cradle {cradleRootDir = "/disk/persist/maralorn/git/nix-output-monitor", cradleOptsProg = CradleAction: Cabal}

Include debug information

1. I tried different hls versions I think I am seeing this with hls 1.4 and 1.6 e.g.
2. I tried with different projects, they all have the issue.
3. I tried a variety of different positions in my filesystem, the issue happened whenever I "cded" into the directory via a symlink.
4. I tried with ghc 8.10 and ghc 9.0.

[maralorn]

I tried to falsify my assumptions, and sure enough I could. I’ll update the issue accordingly.

[maralorn]

I am starting to doubt my sanity here. I think the issue I am describing exists somehow, though the actual symptom, i.e. the need to regularly restart the language-server I can‘t reproduce anymore …

I have edited the issue accordingly.

[fendor]

Maybe this PR is related if the issue is truly related to symlinks: #2359

[michaelpj]

@maralorn do you still see this?

[maralorn]

Oh, phew. I have no clue. I can say that I have developed fine one the directory in question for the last year, so no need to chase ghosts here.