Copy and tweak code from Library/Homebrew/system_config.rb:110 to commit
and date information. This information can be useful when debugging
formulae in custom taps to ensure the tap has been correctly updated
recently or to suss out important differences from one version of a tap
to another.
This removes the need to ask users to run something like
git -C $(brew --repository)/Library/Taps/<tap> show -s --decorate
Close https://github.com/Homebrew/brew/issues/18381
We were selectively requiring the tap.rb file in a few places for
performance reasons. The main method we were referencing was the
`Tap.cmd_directories` method which uses `Pathname` and the `TAP_DIRECTORY`
constant internally. `Tap.cmd_directories` is mostly used in the `Commands`
module and that is loaded very early on in the program so it made sense
to move that command to that module. To facilitate that I moved the
`TAP_DIRECTORY` constant to the top-level and renamed it to
`HOMEBREW_TAP_DIRECTORY`. It now lies in the tap_constants.rb file.
A nice bonus of this refactor is that it speeds up loading external
commands since the tap.rb file is no longer required by default in
those cases.
This improves the load time of most brew commands. For an example of
one of the simplest commands this speeds up:
Without Bootsnap:
```
$ hyperfine 'git checkout master; brew help' 'git checkout optimise_requires; brew help'
Benchmark 1: git checkout master; brew help
Time (mean ± σ): 525.0 ms ± 35.8 ms [User: 229.9 ms, System: 113.1 ms]
Range (min … max): 465.3 ms … 576.6 ms 10 runs
Benchmark 2: git checkout optimise_requires; brew help
Time (mean ± σ): 383.3 ms ± 25.1 ms [User: 133.0 ms, System: 72.1 ms]
Range (min … max): 353.0 ms … 443.6 ms 10 runs
Summary
git checkout optimise_requires; brew help ran
1.37 ± 0.13 times faster than git checkout master; brew help
```
With Bootsnap:
```
$ hyperfine 'git checkout master; brew help' 'git checkout optimise_requires; brew help'
Benchmark 1: git checkout master; brew help
Time (mean ± σ): 386.0 ms ± 30.9 ms [User: 130.2 ms, System: 93.8 ms]
Range (min … max): 359.5 ms … 469.3 ms 10 runs
Benchmark 2: git checkout optimise_requires; brew help
Time (mean ± σ): 330.2 ms ± 32.4 ms [User: 93.4 ms, System: 73.0 ms]
Range (min … max): 302.9 ms … 413.9 ms 10 runs
Summary
git checkout optimise_requires; brew help ran
1.17 ± 0.15 times faster than git checkout master; brew help
```
When homebrew/core or homebrew/cask are untapped `brew tap-info` fails because
Tap.each includes them and tap.private? fails without a git repo interrogate.
This restores the behavior of `brew tap-info` before #16710
Previously, we required all formulae and casks to be in a specific
formula or cask directory but did not check any subdirectories.
This commit allows using subdirectories for official taps, the only
ones likely to be big enough to warrant sharding in this way and to
avoid potentially breaking backwards compatibility for existing taps.
This was inspired by the most recent issues with homebrew-cask.
