Implement support for nightlies

[hasufell]

References:

• https://discourse.haskell.org/t/ghc-nightlies-how-would-you-use-them/5655
• https://docs.google.com/document/d/1KubKWttP5RlvUs0EhUGanIG5FcrK7Ch4HaZ90MSR1r8/edit

@mpickering @david-christiansen @bgamari

[hasufell]

WIP PR: #825

[mpickering]

GHC Metadata MR: https://gitlab.haskell.org/ghc/ghc/-/merge_requests/10373

[hasufell]

User interface

query nightlies in a specific range

Nightlies are hidden by default due to the amount of entries. Installed versions are always shown regardless.

$ ghcup list --show-nightly --since 2022-12-07 --until 2022-12-31
   Tool Version        Tags                         Notes
✗  ghc  9.6.0.20221207 nightly,base-4.18.0.0        2022-12-07
✗  ghc  9.6.0.20221208 nightly,base-4.18.0.0        2022-12-08
✗  ghc  9.6.0.20221209 nightly,base-4.18.0.0        2022-12-09
✗  ghc  9.6.0.20221210 nightly,base-4.18.0.0        2022-12-10
✗  ghc  9.6.0.20221211 nightly,base-4.18.0.0        2022-12-11
✗  ghc  9.6.0.20221212 nightly,base-4.18.0.0        2022-12-12
✗  ghc  9.6.0.20221213 nightly,base-4.18.0.0        2022-12-13
✗  ghc  9.6.0.20221214 nightly,base-4.18.0.0        2022-12-14
✗  ghc  9.6.0.20221215 nightly,base-4.18.0.0        2022-12-15
✗  ghc  9.6.0.20221216 nightly,base-4.18.0.0        2022-12-16
✗  ghc  9.6.0.20221217 nightly,base-4.18.0.0        2022-12-17
✗  ghc  9.6.0.20221218 nightly,base-4.18.0.0        2022-12-18
✗  ghc  9.6.0.20221219 nightly,base-4.18.0.0        2022-12-19
✗  ghc  9.6.0.20221220 nightly,base-4.18.0.0        2022-12-20
✗  ghc  9.6.0.20221221 nightly,base-4.18.0.0        2022-12-21
✗  ghc  9.6.0.20221222 nightly,base-4.18.0.0        2022-12-22
✗  ghc  9.6.0.20221223 nightly,base-4.18.0.0        2022-12-23
✗  ghc  9.6.0.20221224 nightly,base-4.18.0.0        2022-12-24
✗  ghc  9.6.0.20221225 nightly,base-4.18.0.0        2022-12-25
✗  ghc  9.6.0.20221226 nightly,base-4.18.0.0        2022-12-26
✗  ghc  9.6.0.20221227 nightly,base-4.18.0.0        2022-12-27
✗  ghc  9.6.0.20221228 nightly,base-4.18.0.0        2022-12-28
✗  ghc  9.6.0.20221229 nightly,base-4.18.0.0        2022-12-29
✗  ghc  9.6.0.20221230 nightly,base-4.18.0.0        2022-12-30
✗  ghc  9.6.0.20221231 latest-nightly,base-4.18.0.0 2022-12-31

Hide nightlies and "old" GHCs:

$ ghcup list --hide-old
   Tool  Version  Tags                      Notes
✗  ghc   8.4.4    base-4.11.1.0
✗  ghc   8.6.5    base-4.12.0.0
✗  ghc   8.8.4    base-4.13.0.0
✓  ghc   8.10.7   base-4.14.3.0             hls-powered
✗  ghc   9.0.2    base-4.15.1.0             hls-powered
✔✔ ghc   9.2.7    recommended,base-4.16.4.0 hls-powered
✗  ghc   9.4.4    base-4.17.0.0             hls-powered
✓  ghc   9.4.5    base-4.17.1.0
✓  ghc   9.6.1    latest,base-4.18.0.0      hls-powered
✓  cabal 3.6.2.0  recommended
✗  cabal 3.8.1.0
✔✔ cabal 3.10.1.0 latest
✗  hls   1.9.1.0
✔✔ hls   1.10.0.0 latest,recommended
✗  stack 2.7.5
✗  stack 2.9.1
✔✔ stack 2.9.3    latest,recommended
✔✔ ghcup 0.1.19.2 latest,recommended

ghcup tui

ghcup tui will only show latest-nightly (and installed nightlies) and none else:

Installation

You can install via date (only nightlies will have the date info attached for now):

$ ghcup install ghc 2022-12-31
[ Info  ] downloading: https://downloads.haskell.org/~ghc/9.6.0.20221231/ghc-9.6.0.20221231-x86_64-rocky8-linux.tar.xz as file /home/hasufell/.ghcup/cache/ghc-9.6.0.20221231-x86_64-rocky8-linux.tar.xz
...

Performance concerns

A nightly metadata for an entire year (365 entries) with 4 bindist entries per day has been generated here: https://gist.github.com/hasufell/ad710e5218969b15b39a1c3eaba2ccfd

It's 840KB big. GHCup parses and prints this in 300ms... that is fast enough. We would expect that a nightly metadata file only contains entries for the running year, so 840KB is the max. At a new year, we'll back up the old one for legacy use.

A note on GHC branches

This is theoretically agnostic of GHC branches as long as the GHC versions are unique. If there are multiple GHC nightly versions per day, a ghcup install ghc 2023-05-05 would pick the highest version.