Optionally store hie files

[aavogt]

I added the following to my ~/.cabal/config

program-default-options
  ghc-options: -fwrite-ide-info

But I do not end up with .hie files in ~/.cabal/store/. I think they should go beside the hi files. Maybe -hiedir needs to be set. I want this because the hoogle/haddock file share/doc/html/<packagename>.txt is missing information about instances of associated types.

cabal --version
cabal-install version 3.8.1.0
compiled using version 3.8.1.0 of the Cabal library 

ghc --version
The Glorious Glasgow Haskell Compilation System, version 8.10.7

[aavogt]

I have success using the following:

diff --git a/Cabal/src/Distribution/Simple/GHC.hs b/Cabal/src/Distribution/Simple/GHC.hs
index c1352dbba..b82cc6372 100644
--- a/Cabal/src/Distribution/Simple/GHC.hs
+++ b/Cabal/src/Distribution/Simple/GHC.hs
@@ -1974,6 +1974,7 @@ installLib    :: Verbosity
 installLib verbosity lbi targetDir dynlibTargetDir _builtDir pkg lib clbi = do
   -- copy .hi files over:
   whenVanilla $ copyModuleFiles "hi"
+  whenVanilla $ copyModuleFiles "hie"
   whenProf    $ copyModuleFiles "p_hi"
   whenShared  $ copyModuleFiles "dyn_hi"
 
diff --git a/Cabal/src/Distribution/Simple/Program/GHC.hs b/Cabal/src/Distribution/Simple/Program/GHC.hs
index 8e7157af8..8fd264c35 100644
--- a/Cabal/src/Distribution/Simple/Program/GHC.hs
+++ b/Cabal/src/Distribution/Simple/Program/GHC.hs
@@ -677,6 +677,7 @@ renderGhcOptions comp _platform@(Platform _arch os) opts
   , concat [ ["-outputdir", dir] | dir <- flag ghcOptOutputDir ]
   , concat [ ["-odir",    dir] | dir <- flag ghcOptObjDir ]
   , concat [ ["-hidir",   dir] | dir <- flag ghcOptHiDir  ]
+  , concat [ ["-hiedir",   dir] | dir <- flag ghcOptHiDir  ]
   , concat [ ["-stubdir", dir] | dir <- flag ghcOptStubDir ]

Now when I remove -fwrite-ide-info I get an install error Error: cabal: Could not find module: Control.Monad.Trans.Instances with any suffix: ["hie"] in the search path: ["dist/build"]. So whenVanilla should be something different. It should either check for -fwrite-ide-info, the presence of hie files, or it might check for a new option that adds the -fwrite-ide-info. Let me know which way I should write the pull request.

[Mikolaj]

This is something about IDEs, right? @jneira: could you ping some cabal devs that use IDE and so would have an opinion?

[jneira]

I think @fendor could have a good vision of the interaction between hie files and cabal

[andreabedini]

I don't think this is necessarily about IDEs. HIE files can be consumed by many other tools (e.g. policeman, calligraphy). I would find it very useful if cabal could store them (e.g. for analysing the whole application depenency graph).

[michaelpj]

I also wonder if this is something that should have a more "official" flag for producing the additional artifacts, much like we have profiling: True maybe we should have ide-files: True?

[nlander]

Hi all, I would like to encourage these changes to be made sooner rather than later. I am working on gotoDefinition for hls as part of Summer of Haskell and I need the hie files to be generated for the changes I will be making. How can I help this process move forward? I have tried out the changes @aavogt proposed above with similar results. I would be happy to work on a pull request, but I don't want to step on your toes, @aavogt.

[aavogt]

@nlander make the pull request. I look forward to using "gotoDefinition for hls".

[nlander]

I believe #9019 solves this issue.