Use implicit-hie when no explicit hie.yaml

[jneira]

• The test suite hangs in my windows 10 😟
• I've tried several projects without hie.yaml and seems to work fine

//cc @Avi-D-coder

[pepeiborra]

See my comment in haskell/haskell-language-server#386 (comment)
What does loadImplicitHieCradle do for projects that have no Cabal/Stack descriptors?

The test suite hangs because lsp-test has a timeout of 30? seconds, thus failing tests become super slow.

[fendor]

LGTM! Thank you!

EDIT: I have just read the comment, and I think this is correct, gen-hie works for cabal and stack projects, only.

[fendor]

Why has this been removed?

[jneira]

Sorry for nor mentioning it, my local windows build was failing due to a segfault in the external interpreter (the thing that line try to fix in ci!)
The ci job has failied for other reason, let's see if it continue failing due to segfault without -fexternal-interpreter after fixin the actual error.
//cc @bubba

[fendor]

We maybe need more code-paths to support stand-alone files.

[jneira]

We maybe need more code-paths to support stand-alone files.

jumm i assumed incorrectly gen-hie would keep the fallback to the direct cradle with no build system present. I'll take a look.

[jneira]

My original plan was use loadImplicitHieCradle and fallback to actual hie-bios loadImplicitCradle in case the first one fails with an error. I did something similar between the implicit and cabal-helper one here: https://github.com/jneira/haskell-language-server/blob/9969b75785ba8d6e5538c177f297008d4038e992/src/Ide/Cradle.hs#L62-L92
But i think we decided in other pr to keep only one path, maybe it is time to reconsider it.

[fendor]

Can we turn loadImplicitHieCradle into loadImplicitHieCradle :: FilePath -> IO (Maybe (Cradle a))? E.g. only return a cradle if it is stack or cabal? If it is Nothing, we can default to hie-bios implicit cradle.

EDIT: My motivation is, that this is essentially a single code-path, since the implicit cradle won't select cabal or stack since it is always covered by implicit-hie.

[jneira]

Well, i am not sure if hie-implicit-cradle (or ghcide?) does not handle standlone files (although gen-hie does not for sure):

D:\ws\haskell\standalone-hs>ghcide
ghcide version: 0.3.0 (GHC: 8.8) (PATH: D:\bin\ghcide.exe)
Ghcide setup tester in D:\ws\haskell\standalone-hs.
Report bugs at https://github.com/digital-asset/ghcide/issues

Step 1/4: Finding files to test in D:\ws\haskell\standalone-hs
Found 1 files

Step 2/4: Looking for hie.yaml files that control setup
Found 1 cradle
  ()

Step 3/4: Initializing the IDE

Step 4/4: Type checking the files
[INFO] Consulting the cradle for "D:\\ws\\haskell\\standalone-hs\\Main.hs"
Output from setting up the cradle Cradle {cradleRootDir = "D:\\ws\\haskell\\standalone-hs", cradleOptsProg = CradleAction: Default}
[INFO] Using interface files cache dir: C:\Users\user\AppData\Local\ghcide\main-da39a3ee5e6b4b0d3255bfef95601890afd80709
[INFO] Making new HscEnv[main]

Completed (1 file worked, 0 files failed)

D:\ws\haskell\standalone-hs>ghcide-impl-hie
ghcide version: 0.3.0 (GHC: 8.8) (PATH: D:\bin\ghcide-impl-hie.exe)
Ghcide setup tester in D:\ws\haskell\standalone-hs.
Report bugs at https://github.com/digital-asset/ghcide/issues

Step 1/4: Finding files to test in D:\ws\haskell\standalone-hs
Found 1 files

Step 2/4: Looking for hie.yaml files that control setup
Found 1 cradle
  ()

Step 3/4: Initializing the IDE

Step 4/4: Type checking the files
[INFO] Consulting the cradle for "D:\\ws\\haskell\\standalone-hs\\Main.hs"
Output from setting up the cradle Cradle {cradleRootDir = "D:\\ws\\haskell\\standalone-hs", cradleOptsProg = CradleAction: Default}
[INFO] Using interface files cache dir: C:\Users\user\AppData\Local\ghcide\main-da39a3ee5e6b4b0d3255bfef95601890afd80709
[INFO] Making new HscEnv[main]

Completed (1 file worked, 0 files failed)

ghcide is HEAD and ghcide-impl-hie is this pr
I will test it with vscode too but maybe @Avi-D-coder could confirm it
I've opened the hs file with this pr version and it works

[pepeiborra]

I think this is great and I'm happy to merge it, but I have a couple of requests that can either be done in this PR of in follow-ups:

1. Inform the user that there is no cradle #788
2. Write the implicit cradle to disk
3. Give the user a choice if there are both stack and cabal project descriptors
4. Delete all the cradle files from ghcide and hls - no longer needed

[fendor]

LGTM, the rest can be adressed in follow-up PRs

[jneira]

I think this is great and I'm happy to merge it, but I have a couple of requests that can either be done in this PR of in follow-ups:

1. Inform the user that there is no cradle #788

2. Write the implicit cradle to disk

3. Give the user a choice if there are both stack and cabal project descriptors

4. Delete all the cradle files from ghcide and hls - no longer needed

Agree with all of them, i would add a fifth one: state in the (at least) the hls readme the cases when the implicit cradle will fail: common stanzas and conditionals that introduce new modules+path definitions. I think (hope?) they are not so frequent but still.