Narrowing range of GHCs able to build Cabal

Cabal project narrows the range of GHCs able to build Cabal-syntax, Cabal, cabal-install-solver, cabal-install, etc. to support 3 years worth of compilers, which currently spans back to GHC 9.4.

To avoid ambiguity: as of now it does not narrow the range of GHCs which Cabal-the-executable is able to drive , e. g., one is still able to use a new Cabal executable to compile their packages with GHC 8.X. It’s only that Cabal source code itself requires from Cabal developers to use a newer GHC.

The motivation is to be able to rely on newer versions of boot libraries, to maintain less shims for backward compatibility and to run fewer CI jobs (validating that backward compatibility), thus reducing barriers to contribute to Cabal.

For comparison, GHC source code is only buildable with the two latest GHC releases.

github.com/haskell/cabal

Narrow GHC support window from 5 to 3 years (#11966)

master ← three-years

opened 11:27PM - 11 Jun 26 UTC

        Bodigrim
      

+28 -656

As discussed in #11723. The last GHC 9.2 was released more than 3 years ago…, which leaves us with GHC 9.4+. Template Α: This PR modifies behaviour or interface Include the following checklist in your PR: * [x] Patches conform to the coding conventions. * [x] Any changes that could be relevant to users have been recorded in the changelog. * [ ] Is the change significant? If so, remember to add significance: significant in the changelog file. * [ ] The documentation has been updated, if necessary. * [ ] Manual QA notes have been included. * [ ] Tests have been added. (Ask for help if you don’t know how to write them! Ask for an exemption if tests are too complex for too little coverage!)