Unify session loading using implicit-hie

[fendor]

Make Wrapper and Session loader use the same logic to avoid
loading logic divergence.

Cleans up existing usages to use infrastructure in place.

Closes #1782

[fendor]

@emilypi Would you mind trying if this fixes your issue?

[pepeiborra]

How do we know that this fixes the issue? It would be great to have a test

[fendor]

I think, we need end-to-end tests to truly prove the issue doesn't occur anymore. The issue was basically that Wrapper and HLS didn't use the same logic for loading a cradle, thus, came to different conclusions regarding the cradle type. As we now unified the logic behaviour, e.g. there is only a single occurence of loadCradle from hie-bios and loadImplicitHieCradle respectively, it should be fixed. (yeah, I know, that is not a test)

Do we have something resembling end-to-end tests?

[jneira]

Do we have something resembling end-to-end tests?

Execute hls-wrapper and hls in a test directory as cli and comparing their outputs about loading the cradle could work?
Maybe if they would have an option to output the cradle loading info, the test could be easier

[emilypi]

@fendor I can confirm this works, calling the executable with HEAD on your branch:

λ athena pact → λ git fix-modref-json* → ../haskell-language-server/dist-newstyle/build/x86_64-linux/ghc-8.8.4/haskell-language-server-1.1.0.0/x/haskell-language-server-wrapper/noopt/build/haskell-language-server-wrapper/haskell-language-server-wrapper

No 'hie.yaml' found. Try to discover the project type!
Run entered for haskell-language-server-wrapper(haskell-language-server-wrapper) Version 1.1.0.0, Git revision 73b472ae33b14d68c6071f01ce85d349ca8ac3ce (2196 commits) x86_64 ghc-8.8.4
Current directory: /home/tapas/haskell/pact
Operating system: linux
Arguments: []
Cradle directory: /home/tapas/haskell/pact
Cradle type: Cabal

Tool versions found on the $PATH
cabal:		3.4.0.0
stack:		2.5.1
ghc:		8.8.4


Consulting the cradle to get project GHC version...
Project GHC version: 8.8.4
haskell-language-server exe candidates: ["haskell-language-server-8.8.4","haskell-language-server-8.8","haskell-language-server"]
Launching haskell-language-server exe at:/home/tapas/.ghcup/bin/haskell-language-server-8.8.4
haskell-language-server version: 1.1.0.0 (GHC: 8.8.4) (PATH: /home/tapas/.ghcup/bin/haskell-language-server-8.8.4~1.1.0) (GIT hash: f1c096927186a93d8e3ccd4fe8385cc1b070350b)
 ghcide setup tester in /home/tapas/haskell/pact.
Report bugs at https://github.com/haskell/haskell-language-server/issues

Step 1/4: Finding files to test in /home/tapas/haskell/pact
Found 154 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
2021-04-30 19:03:43.657015867 [ThreadId 180] INFO hls:	Consulting the cradle for "src/Pact/Native/Decrypt.hs"
2021-04-30 19:03:43.657125598 [ThreadId 180] WARNING hls:	No [cradle](https://github.com/mpickering/hie-bios#hie-bios) found for src/Pact/Native/Decrypt.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.
Output from setting up the cradle Cradle {cradleRootDir = "/home/tapas/haskell/pact", cradleOptsProg = CradleAction: Cabal}
> Build profile: -w ghc-8.8.4 -O0
> In order, the following will be built (use -v for more details):
>  - pact-3.7 (lib) (ephemeral targets)
> Preprocessing library for pact-3.7..
2021-04-30 19:03:44.221938537 [ThreadId 180] INFO hls:	Using interface files cache dir: /home/tapas/.cache/ghcide/pact-3.7-inplace-64068f8443af49203e4e0b3f9e4d9e46a17947f8
2021-04-30 19:03:44.222399518 [ThreadId 180] INFO hls:	Making new HscEnv[pact-3.7-inplace]
2021-04-30 19:03:44.55223189 [ThreadId 346] INFO hls:	Consulting the cradle for "tests/RemoteVerifySpec.hs"
2021-04-30 19:03:44.552312195 [ThreadId 346] WARNING hls:	No [cradle](https://github.com/mpickering/hie-bios#hie-bios) found for tests/RemoteVerifySpec.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.
Output from setting up the cradle Cradle {cradleRootDir = "/home/tapas/haskell/pact", cradleOptsProg = CradleAction: Cabal}
> Build profile: -w ghc-8.8.4 -O0
> In order, the following will be built (use -v for more details):
>  - pact-3.7 (test:hspec) (first run)
> Preprocessing test suite 'hspec' for pact-3.7..
2021-04-30 19:03:45.110849156 [ThreadId 346] INFO hls:	Using interface files cache dir: /home/tapas/.cache/ghcide/main-c5aeed3c2a1678cab0565680a4f4f9f919a921e5
2021-04-30 19:03:45.111137213 [ThreadId 346] INFO hls:	Using interface files cache dir: /home/tapas/.cache/ghcide/pact-3.7-inplace-a180612acf9c0a749f459cf6d98fb3b41cb90260
2021-04-30 19:03:45.111395534 [ThreadId 346] INFO hls:	Making new HscEnv[main,pact-3.7-inplace]
2021-04-30 19:03:45.355579071 [ThreadId 398] INFO hls:	Consulting the cradle for "HLint.hs"
2021-04-30 19:03:45.355655464 [ThreadId 398] WARNING hls:	No [cradle](https://github.com/mpickering/hie-bios#hie-bios) found for HLint.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.
Output from setting up the cradle Cradle {cradleRootDir = "/home/tapas/haskell/pact", cradleOptsProg = CradleAction: Cabal}

[fendor]

Added a test as suggested by @jneira

Implements new major mode BiosMode that prints the cradle type and could be expanded in the future for more hie-bios commands.

I had troubles running the tests locally, let's see what CI says.

[fendor]

As per usual, you spend more time on trying to write tests than actually solving the issue.

I think this is ready for review

[jneira]

LGTM, great job @fendor, as usual
I hope the new cli option will be helpful beyond this concrete issue.