tl;dr. We propose that GHC more aggressively bump its boot library dependencies. Hello all, Historically, GHC minor releases have been quite conservative in bumping boot library versions, generally defaulting to retaining the versions used in the GHC-x.y.1 release unless * a request is made by a boot library maintainer, or * we discover an issue which warrants a bump The motivation for this policy is both to * minimize the potential for regressions in correctness and performance, and * reduce the potential for end-user breakage due to interface changes as even minor releases can result in considerable impact (e.g. #25411, #22633) While this policy has served us well, its conservative nature demands the vigilence of both GHC and upstream maintainers to ensure that bumps that are truly necessary do not fall through the cracks. As the flaws of this process have been more apparent recently (e.g. #24597), we have done a bit of reflection on how we might improve the status quo. Concretely, I would like feedback on the adopting the following policy going forward:
Unless guidance is provided otherwise by a library maintainer, a GHC x.y.z release will attempt to ship the newest minor version of each boot libray in the same major series shipped with GHC x.y.1.
I believe this policy would leave less room for human error and open opportunities for automated checking. On the other hand, the more aggressive bumping of submodules may mean that users are hit with more (usually minor) compatibility issues when moving between minor GHC releases. How do others feel about this? We are particularly interested to hear from boot library maintainers but feedback from packagers and users is also very much welcome. Cheers, - Ben