Questions regarding the right strategy for upgrading to ghc-9.8

[lucasdicioccio]

Hi there, I'm attempting to increase this repository to ghc-9.8.2 with an aim for a Hackage release (so that my blog-engine can be on Hackage as well) at some point before this summer (personal reasons for the deadline). I work on a fork at https://github.com/lucasdicioccio/dhall-haskell .

My patch is not ready yet but an early attempt shows:

• a few bounds could be/would have to be relaxed
• some deeper failures will need bound-relaxing/uploads as well (hnix for dhall-lsp-server, dhall-nix and dhall-nixpkgs)
• some CPP will be needed to support (without warning) old imports (liftA2 being part of the class Control.Applicative)
• some rework around (safe? -- i haven't convinced myself) calls to Prelude.head which turns a deprecation warning
• my auto-formatting vim autocommand to fourmolu-format on save trapped me
• some more CPP needed as megaparsec now has an additional packages

I don't mind continuing, however I'm interested to know whether:

• are you aware of someone already on a further track than myself?
• is there some target-compatibility level with older GHCs/megaparsec? (to cut on CPP)
• is there some plan to fourmolu-format the code (in which case I'd rather see that done in a lockstep before xor after porting to 9.8.2 to reduce diff noise/rebase conflicts)?

[ysangkok]

dhall-1.42.2 is out which offers compatibility:

% cabal repl -b dhall -w ghc-9.8.4
Resolving dependencies...
Build profile: -w ghc-9.8.4 -O1
In order, the following will be built (use -v for more details):
 - aeson-2.2.3.0 (lib) (requires build)
 - atomic-write-0.2.1.0 (lib) (requires download & build)
 - megaparsec-9.7.0 (lib) (requires build)
 - parsers-0.12.12 (lib) (requires download & build)
 - streaming-commons-0.2.3.0 (lib) (requires download & build)
 - tls-2.1.7 (lib) (requires download & build)
 - aeson-pretty-0.8.10 (lib) (requires build)
 - http-client-0.7.18 (lib) (requires build)
 - crypton-connection-0.4.3 (lib) (requires build)
 - cborg-json-0.2.6.0 (lib) (requires download & build)
 - http-client-tls-0.3.6.4 (lib) (requires build)
 - dhall-1.42.2 (lib) (requires download & build)
 - fake-package-0 (interactive) (lib) (first run)

Is there anything else that needs to get done for this issue to get closed?

[lucasdicioccio]

@ysangkok no if 9.8.4 works I'm good. Thanks for letting me know. I'll upgrade my downstream dependency.