Haskell stack needs 2.5gb of space

[bmacho]

Also it needs 5 gb of free space for installation.

I can't test my solutions without it. That's a bit extreme space requirement, just for checking if two values are equal.

Wouldn't it be possible and desirable to test only with ghc/ghci, without the need of the whole stack?

[github-actions]

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[SleeplessByte]

cc @exercism/haskell

[bmacho]

Okay, with some random things I was able to test the hello world example, with 80MB of the stack binary, and 40MB of .stack folder. I don't know exactly what caused it ( I random copied things from https://wiki.archlinux.org/title/Haskell#Configuring_Stack_for_dynamic_linking ) but maybe this will do:

• get the stack binary, and don't start it yet
• paste

# Stop downloading GHCs into isolated locations under ~/.stack.
install-ghc: false

# Allow Stack to pick the system GHC (false by default).
system-ghc: true

# Add the -dynamic flag to every invocation of GHC.
ghc-options:
  "$everything": -dynamic

into ~/.stack/config.yaml

check your GHC version, and find a suitable resolver version here https://www.stackage.org/
E.g. for my ghc 8.6.5, lts-14.27 was it.

Modify the stack.yaml file in the exercise folder, to match your version, in my case, I changed resolver: lts-18.14 to resolver: lts-14.27.
That's it, if you run stack test, it will still download and compile some necessary packages (e.g. I don't think I had Test.Hspec installed previously), but only them. In my case it needed 40MB instead of 5 GB of space.

[petertseng]

I usually run runghc -Wall -isrc test/Tests.hs since I don't have Stack installed. But I had not put that command in the documentation because... actually, I don't remember why. If there were some guidance that said "Your language track should only endorse one way of doing things because presenting more choices would just be more confusing" then I guess that would preclude adding it, but I don't recall that there is any guidance to that effect.

So that means here are my two suggestions, either or both of which can be tackled.

First, I'd like to find a good place to put the runghc -Wall -isrc test/Tests.hs command in, for those who don't want Stack or cannot install it for any reason. We would probably put it in https://github.com/exercism/haskell/blob/main/docs/TESTS.md. Perhaps https://github.com/exercism/haskell/blob/main/docs/INSTALLATION.md might also need to change, if we are going to present the alternative of not using Stack.

Second, if the directions presented to have Stack use system GHC are minimal and complete, they can be added. Will need to think about how to present them - is that something we're recommending to everyone, or is it just to those who want it? Will there be issues with students not being sure how to correctly follow the instructions, or whether they should even follow them at all? etc.

[bmacho]

On my Ubuntu system, sudo apt intsall libghc-hspec-dev provides the needing dependencies, and runghc -Wall -isrc test/Tests.hs works. (With GHC also from the repository.)
At least on the hello world example, I am not sure how far can one go with this space-optimized approach.

[petertseng]

By minimal, I do not mean that it uses as little space as possible, but that there are no extraneous steps that can be removed. By complete, I mean that no steps are missing. Following the steps is all that is needed to use system GHC.

From my understanding of the steps, they meet these requirements, so no further modification to those steps is needed.

I have opened #1036 and #1037 in the Haskell track repo.

[ErikSchierboom]

@petertseng I've moved this to the haskell repo. Feel free to close this if you feel this is handled by the above mentioned issues.

[petertseng]

Yes, I confirm that the above two issues are the actions that should be taken in response to this issue.