replace shell.nix with Nix Flake

[peterbecich]

I think this will speed up the CI build time (#1078) plus other benefits

---

TODO

• fix Mac building
  • Mac & Linux support of Flake template input-output-hk/haskell.nix#1825
  • temp fix is to replace https://github.com/peterbecich/hackage-server/blob/bc488232304f63cb2ee499c32a151f601b98adb1/flake.nix#L22 with x86_64-darwin or aarch64-darwin
• remove LegacyPasswd code and dependency on crypt #1153
  • see this issue with nix flake check
• fix DocTest
  • doctest-parallel error input-output-hk/haskell.nix#1829
  • Doctest is broken input-output-hk/haskell.nix#221 (comment)

[gbaz]

Peter -- you're more qualified than me on this stuff, so I just went ahead and invited you to the hackage team so you should be able to merge prs on this repo. Please only do so unilaterally with safe-ish build/nix stuff :-)

[peterbecich]

Great, thanks, understood

[peterbecich]

Please review part of this PR, deletion of Basic Auth: #1165

[peterbecich]

Trying to fix the DocTests error: input-output-hk/haskell.nix#1829

[andreasabel]

Any justification for this new lower bound? (Add to the comment below it.)
I suppose it should also be given an upper bound.

[peterbecich]

Running the DocTests in the Flake currently has an error. I'm not sure yet if the error is in haskell.nix, doctest-parallel, or some other place

Investigating
input-output-hk/haskell.nix#1829
martijnbastiaan/doctest-parallel#66

[peterbecich]

replacing ghc with ghc-lib in doctests-parallel produces a different error, but I think it may be a step in the right direction

[peterbecich]

about doctest-parallel
martijnbastiaan/doctest-parallel#65 (comment)

hackage-server/cabal.project

Lines 13 to 22 in 24b1e75

	-- Andreas, 2022-10-28: `Cabal-3.8.1.0` wants `process >= 1.6.14`
	-- which is too new for the `ghc < 9.4` package that is pulled in
	-- by `doctest-parallel`.
	-- Since, Cabal-3.8.1.0 has no reason to want such a new version
	-- of process, we can solve the conflict here by allowing
	-- `Cabal` to use the shipped version of `process`.
	-- This workaround can be removed once `Cabal-3.8` drops
	-- its (unreasonable) constraint on `process`.
	-- See: https://github.com/haskell/cabal/issues/8554
	allow-older: Cabal:process

[andreasabel]

@peterbecich , FYI:

• The doctest conundrum should now be fixed due to revisions I made to Cabal.
• I switched the nix CI off on master as it malfunctioned over a long time. (But I am aware that you are working on a fix.)

[peterbecich]

@andreasabel

• thanks, I will check nix flake check again, if the doctest-parallel issue is resolved we can close: doctest-parallel error input-output-hk/haskell.nix#1829
• there may be a separate issue with building the gd library in nix develop shell: failure to build gd Hackage library in nix develop shell input-output-hk/haskell.nix#1865
  • can we remove the dependency on https://hackage.haskell.org/package/gd-3000.7.3 ? it was last updated over 10 years ago

We can also try using https://github.com/srid/haskell-flake instead of haskell.nix; I have tried this, it pulls Hackage dependencies from Nix Pkgs instead of https://github.com/input-output-hk/hackage.nix, the work involved is to pin the correct dependencies from Nix Pkgs

[andreasabel]

• can we remove the dependency on hackage.haskell.org/package/gd-3000.7.3 ? it was last updated over 10 years ago

Ah, yes, I was suprised that I had to add libgd-dev to CI yesterday, I thought we maybe had new features requiring it. But gd comes to us via hs-captcha (last updated in 2009). We use it here:

hackage-server/src/Distribution/Server/Features/UserSignup.hs

Line 45 in 08d61eb

import Graphics.Captcha

hackage-server/src/Distribution/Server/Features/UserSignup.hs

Lines 437 to 441 in 08d61eb

	makeCaptchaHash :: IO (UTCTime, BS.ByteString, BS.ByteString)
	makeCaptchaHash = do
	(code, image) <- makeCaptcha
	timestamp <- getCurrentTime
	pure (timestamp, hashTimeAndCaptcha timestamp code, fromString "data:image/png;base64," <> Base64.encode image)