Allow compilation with ghc 8.10.7

[nitinprakash96]

Need to allow GHC 8.10.7.
Current build on master:

λ  servant-hmac-auth git:(master) ✗ stack build --resolver lts-18.21

Error: While constructing the build plan, the following exceptions were encountered:

In the dependencies for servant-hmac-auth-0.1.3:
    base64-bytestring-1.1.0.0 from stack configuration does not match ^>=1.0  (latest matching version is 1.0.0.3)
needed since servant-hmac-auth is a build target.

Some different approaches to resolving this:

  * Set 'allow-newer: true' in /Users/nitin/.stack/config.yaml to ignore all version constraints and build anyway.

  * Recommended action: try adding the following to your extra-deps in /Users/nitin/Documents/temp/servant-hmac-auth/stack.yaml:

- base64-bytestring-1.0.0.3@sha256:d5027ea6d63eab27cfa34eb1f5a05b6a5ee521dd176a06da3f7d80e117a88259,2352

[jhrcek]

If you want these stack commands to use the stack yaml files, you'll have to specify it on cli,
something like stack build .... --stack-yaml stack-${{ matrix.ghc }}.yaml

Otherwise they'll just use the stack.yaml.

Also if you want to use the ghc installed by haskell/actions/setup@v1
you should add --system-ghc to all the stack commands (otherwise stack will install its own GHC and ignore the ghc installation provided by that setup action.

[jhrcek]

You can see it's downloading ghc-8.8.3 in 8.10.7 job
which is because the stack.yaml specifies lts-16.2 which uses ghc 8.8.3

[nitinprakash96]

Thanks for pointing this out. I did not realise this was happening.

[turboMaCk]

I like to use lazy approach to this. Rather than being forced to check everything all the time use the workflow where it's hard to miss the problem. If you want to make something build with new version of compiler, start by replicating compilation error in ci. Only then attempt to fix it.

[jhrcek]

Please add cli arguments to use --system-ghc and --stack-yaml stack-${{ matrix.ghc }}.yaml to all stack invocations. You'll also probably need to rename stack.yaml to stack-8.8.4.yaml and use some resolver that depends on 8.8.4 (e.g. latest 17: https://www.stackage.org/lts-17.15)

[jhrcek]

Sorry, forgot to click "request changes"

[jhrcek]

It's possible you'll no longer be able to build with GHC 8.6.5, due to constraints introduced in 75599c2

In that case I'd recommend simply dropping ghc 8.6.5.
Also I'd recommend using GHC 8.8.4 (latest in 8.8 series) instead of 8.8.3.

[jhrcek]

Or alternatively you can just add appropriate extra-deps to stack-8.6.5.yaml.

[jhrcek]

Almost there 😄

[jhrcek]

Looks great, thank you!
I love the consistent formatting 👍