stack 2.1.1 ends up with Cabal 2.4.0.1 and 2.4.1.0 in the package environment

[alanz]

General summary/comments (optional)

When building a test project against lts-13.23, the dist dir ends up being ..stack-work/dist/x86_64-linux-tinfo6/Cabal-2.4.0.1.

The snapshot has Cabal-2.4.1.0 in it.

When compiling the project (admittedly by using cabal-helper at https://github.com/alanz/cabal-helper/tree/wip/new-build) it errors because both Cabal library versions are present. This can (and will) be fixed in cabal-helper.

But why is stack not using Cabal-2.4.1.0?

[qrilka]

I suppose the comments in this issue shine some light on your question @alanz - #4488
The main motivation as I see it is just to save user's time because building Cabal takes quite substantial time

[alanz]

@qrilka Thanks, I just checked, and see that GHC 8.6.4 and 8.6.5 both ship with Cabal 2.4.0.1.

So I will continue delving into the problem in cabal-helper

[alanz]

If anyone is interested, I got this working via alanz/haskell-ide-engine@40f9c88, which does

    unsetEnv "GHC_PACKAGE_PATH"
    unsetEnv "GHC_ENVIRONMENT"
    unsetEnv "HASKELL_PACKAGE_SANDBOX"
    unsetEnv "HASKELL_PACKAGE_SANDBOXES"

before running the process invoking cabal-helper.