Haskell-ide-engine: Not working with cabal-2.4.1.0

[newhoggy]

Looks like the setup-config is located in a slightly different location when building with cabal-2.4.1.0:

$  /Users/jky/wrk/haskell-works/haskell-ide-engine-6/.stack-work/install/x86_64-osx/lts-12.14/8.4.3/bin/cabal-helper-wrapper "--with-ghc=ghc" "--with-ghc-pkg=ghc-pkg" "--with-cabal=cabal" "v1-style" "/Users/jky/wrk/haskell-works/hw-json" "/Users/jky/wrk/haskell-works/hw-json/dist-newstyle/build/x86_64-osx/ghc-8.4.3/hw-json-0.9.0.1" "package-db-stack" "flags" "compiler-version" "ghc-merged-pkg-options" "config-flags" "non-default-config-flags" "ghc-src-options" "ghc-pkg-options" "ghc-lang-options" "ghc-options" "source-dirs" "entrypoints" "needs-build-output"
cabal-helper-wrapper: /Users/jky/wrk/haskell-works/hw-json/dist-newstyle/build/x86_64-osx/ghc-8.4.3/hw-json-0.9.0.1/setup-config: openFile: does not exist (No such file or directory)
$ find dist-newstyle -name setup-config
dist-newstyle/build/x86_64-osx/ghc-8.4.3/hw-json-0.9.0.1/t/hw-json-test/opt/setup-config
dist-newstyle/build/x86_64-osx/ghc-8.4.3/hw-json-0.9.0.1/opt/setup-config

[newhoggy]

Notice that haskell-ide-engine expects the file to be located here:

dist-newstyle/build/x86_64-osx/ghc-8.4.3/hw-json-0.9.0.1/setup-config

but it is actually found here:

dist-newstyle/build/x86_64-osx/ghc-8.4.3/hw-json-0.9.0.1/opt/setup-config

It is unclear if it is the cabal version that is causing this difference or if it is the cabal file version, which I've specified like this:

$ head -n 1 hw-json.cabal
cabal-version:  2.2

[newhoggy]

After downgrading my cabal file to remove cabal-version: 2.2 and add cabal-version: >= 1.10, the problem still persists.

[newhoggy]

Work around:

$ cd dist-newstyle/build/x86_64-osx/ghc-8.4.3/hw-json-0.9.0.1/
$ ln -s opt/setup-config setup-config

[newhoggy]

Work around in the general case:

# haskell-ide-engine work-around
for x in $(find dist-newstyle -name setup-config | grep '/opt/setup-config$' | sed 's|/opt/setup-config$||g'); do
  ( cd $x
    ln -fs opt/setup-config setup-config
  )
done

[alanz]

@newhoggy this is a problem with new-build in general, and the interim support we have at the moment, which basically only supports the library component.

[AlexeyRaga]

Reading setup-config seems to be unreliable anyway because producing it requires new-build to be executed first. Even new-configure doesn't seem to be enough.

One of the implications is that changing the version number in a .cabal file changes the path to the file which doesn't exist until new-build is issued so the IDE reports readCreateProcess errors.
Which is not an ideal user experience.

Can it be worked around without requiring setup-config to be there?

[AlexeyRaga]

I am curious, should we be using v2-style instead in the cabal helper?
Since dist-newstyle/cache/plan.json is in an "easier" location and it is generated by cabal new-configure we could use it, and issue cabal new-configure automatically when it is not present?

I wanted to try, but I see that to v2-style I should provide something that is called Unit, which is, perhaps, looks something like <my-executable-name>-<version>-inplace and this is where I am a bit lost. Which one do I suppose to use? How do I determine the "right" executable name, assuming that there can be >1 of them in the cabal file?

Can anyone provide a direction here?

[alanz]

@AlexeyRaga , the proper new-build support is coming via https://github.com/alanz/haskell-ide-engine/tree/bleeding-edge-c-h

It sort of works at the moment, but has issues with caching, and detecting changes in the project being developed.

[AlexeyRaga]

@alanz awesome, thanks! :) Can't wait! :)

[tjarvstrand]

Any news? I'm eagerly awaiting this! :)

[alanz]

@DanielG has managed to find some time to work on this solidly in the next few months, so rather than doing my band-aid patch, we will wait for his work.

And we are hoping for some assistance from @power-fungus and @fendor too.

[masaeedu]

@alanz Can we document in the README that executable support is currently not working and users should work with library stanzas instead?

[fendor]

We can do that.

[razvan-flavius-panda]

@masaeedu is it possible to use the library stanza yet compile to an executable?

@newhoggy I created a link of setup-config under /dist-newstyle/build/x86_64-linux/ghc-8.6.5/app-0.1.0.0 and when I launch Atom I still receive error:

readCreateProcess: /nix/store/jq8x50rkl3cm7cqkj1zsk6kfbb692iwv-cabal-helper-0.9.0.0/bin/cabal-helper-wrapper "--with-ghc=ghc" "--with-ghc-pkg=ghc-pkg" "--with-cabal=cabal" "v1-style" "/home/neo/Sources/miso/sample-app" "/home/neo/Sources/miso/sample-app/dist-newstyle/build/x86_64-linux/ghc-8.6.5/app-0.1.0.0" "package-db-stack" "flags" "compiler-version" "ghc-merged-pkg-options" "config-flags" "non-default-config-flags" "ghc-src-options" "ghc-pkg-options" "ghc-lang-options" "ghc-options" "source-dirs" "entrypoints" "needs-build-output" (exit 1): failed

Also, why is the command above from HIE calling v1-style when I only have a dist-newstyle folder and a cabal.project?

[fendor]

Because HIE can only handle cabal v1-projects at the moment. Support for cabal v2 is coming via #1126

[jneira]

is it possible to use the library stanza yet compile to an executable?

Afaik it is not.

I created a link of setup-config under /dist-newstyle/build/x86_64-linux/ghc-8.6.5/app-0.1.0.0 and when I launch Atom I still receive error

Could you run the command in a shell to try to get a more informative error?

Because HIE can only handle cabal v1-projects at the moment. Support for cabal v2 is coming via #1126

Well, i would add "... in a reliable way for most environments" to that.

In my case i've got to use haskell-ide-engine with a simple cabal based project built with v2-build for both the executable and library, without any hard link:

• With cabal-2.4.1.0 in $PATH

cabal-install version 2.4.1.0
compiled using version 2.4.1.0 of the Cabal library

• With ghc-8.6.5 shipped with Cabal-2.4.0.1
• In a windows system
• Testing with vscode
• After deleting the cabal-helper cache (in my case in %USERPROFILE%\Local settings\Cache\cabal-helper
• After run cabal v2-clean && cabal v2-configure in the project
• hie-version: Version 0.12.0.0 x86_64 ghc-8.6.5 (actual 25678ff00 built from source with cabal-3.0.0.0 using stack install.hs cabal-hie-8.6.5)
• hie generated this cabal-helper call:

D:\csd\ghc-8.6.5\cabal-helper-0.9.0.0-968d5c7983449350a92033da9a1c8934178545ff\bin\cabal-helper-wrapper.exe "--with-ghc=ghc" "--with-ghc-pkg=ghc-pkg" "--with-cabal=cabal" "v1-style" "D:\ws\haskell\cabal-test" "D:\ws\haskell\cabal-test\dist-newstyle/build\x86_64-windows\ghc-8.6.5\cabal-test-0.1.0.0" "package-db-stack" "flags" "compiler-version" "ghc-merged-pkg-options" "config-flags" "non-default-config-flags" "ghc-src-options" "ghc-pkg-options" "ghc-lang-options" "ghc-options" "source-dirs" "entrypoints" "needs-build-output"

• Note:
  
  
  
  • It has the v1-style option although it is able to handle the project built with v2
  
  
  • It has the correct path to setup-config within the new style build dir: D:\ws\haskell\cabal-test\dist-newstyle\build\x86_64-windows\ghc-8.6.5\cabal-test-0.1.0.0 (no need to hard link another path). In my case there is not an opt subdir... so maybe in macos the hard link is needed
  
  
  • It built cabal-helper0.9.0.0-Cabal2.4.1.0 in %USERPROFILE%\Local settings\Cache\cabal-helper
    
    (log of hie output in https://gist.github.com/jneira/918048bb504b208239d97d894b9e56c9)
  
  

[razvan-flavius-panda]

@jneira no luck for me, I still got the readCreateProcess error after following your steps.

[jneira]

We could trace the error thrown by cabal-helper and eventually got to make it work with some effort, but i would follow @fendor suggestion and wait for the mentioned pr and use stack in the meanwhile if you can use it.
Feel free to post the error thrown by executing cabal-helper-wrapper in a shell otherwise.

[fendor]

1126 has landed bringing support for cabal v2-* builds!