Speedup brew --version.

Port `brew --version` to Bash to speed it up.

While we're here:
- remove (now) unused `Tap` Git methods
- use `--quiet` instead of `-q` to be more verbose

Benchmarks:
```
$ hyperfine --min-runs=3 --warmup=2 "git checkout origin/master; brew --version" "git checkout speedup_brew_version; brew --version"
Benchmark #1: git checkout origin/master; brew --version
  Time (mean ± σ):      2.083 s ±  0.004 s    [User: 396.8 ms, System: 597.2 ms]
  Range (min … max):    2.080 s …  2.088 s    3 runs

Benchmark #2: git checkout speedup_brew_version; brew --version
  Time (mean ± σ):     847.9 ms ±  35.2 ms    [User: 100.0 ms, System: 247.9 ms]
  Range (min … max):   824.1 ms … 888.3 ms    3 runs

Summary
  'git checkout speedup_brew_version; brew --version' ran
    2.46 ± 0.10 times faster than 'git checkout origin/master; brew --version'
```

Library/Homebrew/brew.sh

@@ -188,9 +188,9 @@ update-preinstall() {
     # last $HOMEBREW_AUTO_UPDATE_SECS.
     if [[ "$HOMEBREW_COMMAND" = "cask" ]]
     then
-      tap_fetch_head="$HOMEBREW_LIBRARY/Taps/homebrew/homebrew-cask/.git/FETCH_HEAD"
+      tap_fetch_head="$HOMEBREW_CASK_REPOSITORY/.git/FETCH_HEAD"
     else
-      tap_fetch_head="$HOMEBREW_LIBRARY/Taps/homebrew/homebrew-core/.git/FETCH_HEAD"
+      tap_fetch_head="$HOMEBREW_CORE_REPOSITORY/.git/FETCH_HEAD"
     fi
     if [[ -f "$tap_fetch_head" &&
           -n "$(find "$tap_fetch_head" -type f -mtime -"${HOMEBREW_AUTO_UPDATE_SECS}"s 2>/dev/null)" ]]
@@ -314,6 +314,15 @@ then
   HOMEBREW_USER_AGENT_VERSION="2.X.Y"
 fi
 
+HOMEBREW_CASK_REPOSITORY="$HOMEBREW_LIBRARY/Taps/homebrew/homebrew-cask"
+HOMEBREW_CORE_REPOSITORY="$HOMEBREW_LIBRARY/Taps/homebrew/homebrew-core"
+
+# Don't need shellcheck to follow these `source`.
+# shellcheck disable=SC1090
+case "$*" in
+  --version|-v) source "$HOMEBREW_LIBRARY/Homebrew/cmd/--version.sh"; homebrew-version; exit 0 ;;
+esac
+
 if [[ -n "$HOMEBREW_MACOS" ]]
 then
   HOMEBREW_PRODUCT="Homebrew"

Library/Homebrew/cmd/--version.rb

@@ -1,30 +0,0 @@
-# typed: true
-# frozen_string_literal: true
-
-require "cli/parser"
-
-module Homebrew
-  extend T::Sig
-
-  module_function
-
-  sig { returns(CLI::Parser) }
-  def __version_args
-    Homebrew::CLI::Parser.new do
-      description <<~EOS
-        Print the version numbers of Homebrew, Homebrew/homebrew-core and Homebrew/homebrew-cask
-        (if tapped) to standard output.
-      EOS
-
-      named_args :none
-    end
-  end
-
-  def __version
-    __version_args.parse
-
-    puts "Homebrew #{HOMEBREW_VERSION}"
-    puts "#{CoreTap.instance.full_name} #{CoreTap.instance.version_string}"
-    puts "#{Tap.default_cask_tap.full_name} #{Tap.default_cask_tap.version_string}" if Tap.default_cask_tap.installed?
-  end
-end

Library/Homebrew/cmd/--version.sh

@@ -0,0 +1,31 @@
+#:  * `--version`, `-v`
+#:
+#:  Print the version numbers of Homebrew, Homebrew/homebrew-core and Homebrew/homebrew-cask (if tapped) to standard output.
+
+version_string() {
+  local repo="$1"
+  if ! [ -d "$repo" ]; then
+    echo "N/A"
+    return
+  fi
+
+  local pretty_revision
+  pretty_revision="$(git -C "$repo" rev-parse --short --verify --quiet HEAD)"
+  if [ -z "$pretty_revision" ]; then
+    echo "(no Git repository)"
+    return
+  fi
+
+  local git_last_commit_date
+  git_last_commit_date=$(git -C "$repo" show -s --format='%cd' --date=short HEAD)
+  echo "(git revision ${pretty_revision}; last commit ${git_last_commit_date})"
+}
+
+homebrew-version() {
+  echo "Homebrew $HOMEBREW_VERSION"
+  echo "Homebrew/homebrew-core $(version_string "$HOMEBREW_CORE_REPOSITORY")"
+
+  if [ -d "$HOMEBREW_CASK_REPOSITORY" ]; then
+    echo "Homebrew/homebrew-cask $(version_string "$HOMEBREW_CASK_REPOSITORY")"
+  fi
+}

Library/Homebrew/extend/git_repository.rb

@@ -32,14 +32,14 @@ module GitRepositoryExtension
   # Gets the full commit hash of the HEAD commit.
   sig { params(safe: T::Boolean).returns(T.nilable(String)) }
   def git_head(safe: false)
-    popen_git("rev-parse", "--verify", "-q", "HEAD", safe: safe)
+    popen_git("rev-parse", "--verify", "--quiet", "HEAD", safe: safe)
   end
 
   # Gets a short commit hash of the HEAD commit.
   sig { params(length: T.nilable(Integer), safe: T::Boolean).returns(T.nilable(String)) }
   def git_short_head(length: nil, safe: false)
     short_arg = length.present? ? "--short=#{length}" : "--short"
-    popen_git("rev-parse", short_arg, "--verify", "-q", "HEAD", safe: safe)
+    popen_git("rev-parse", short_arg, "--verify", "--quiet", "HEAD", safe: safe)
   end
 
   # Gets the relative date of the last commit, e.g. "1 hour ago"

Library/Homebrew/tap.rb

@@ -170,13 +170,6 @@ class Tap
     path.git_head
   end
 
-  # git HEAD in short format for this {Tap}.
-  def git_short_head
-    raise TapUnavailableError, name unless installed?
-
-    path.git_short_head(length: 4)
-  end
-
   # Time since last git commit for this {Tap}.
   def git_last_commit
     raise TapUnavailableError, name unless installed?
@@ -184,13 +177,6 @@ class Tap
     path.git_last_commit
   end
 
-  # Last git commit date for this {Tap}.
-  def git_last_commit_date
-    raise TapUnavailableError, name unless installed?
-
-    path.git_last_commit_date
-  end
-
   # The issues URL of this {Tap}.
   # e.g. `https://github.com/user/homebrew-repo/issues`
   sig { returns(T.nilable(String)) }
@@ -204,16 +190,6 @@ class Tap
     name
   end
 
-  sig { returns(String) }
-  def version_string
-    return "N/A" unless installed?
-
-    pretty_revision = git_short_head
-    return "(no Git repository)" unless pretty_revision
-
-    "(git revision #{pretty_revision}; last commit #{git_last_commit_date})"
-  end
-
   # True if this {Tap} is an official Homebrew tap.
   def official?
     user == "Homebrew"

Library/Homebrew/test/cmd/--version_spec.rb

@@ -4,10 +4,8 @@
 require "cmd/shared_examples/args_parse"
 
 describe "brew --version" do
-  it_behaves_like "parseable arguments"
-
-  it "prints the Homebrew version", :integration_test do
-    expect { brew "--version" }
+  it "prints the Homebrew's version", :integration_test do
+    expect { brew_sh "--version" }
       .to output(/^Homebrew #{Regexp.escape(HOMEBREW_VERSION)}\n/o).to_stdout
       .and not_to_output.to_stderr
       .and be_a_success

Library/Homebrew/test/support/helper/spec/shared_context/integration_test.rb

@@ -124,6 +124,15 @@ RSpec.shared_context "integration test" do # rubocop:disable RSpec/ContextWordin
     end
   end
 
+  def brew_sh(*args)
+    Bundler.with_clean_env do
+      stdout, stderr, status = Open3.capture3("#{ENV["HOMEBREW_PREFIX"]}/bin/brew", *args)
+      $stdout.print stdout
+      $stderr.print stderr
+      status
+    end
+  end
+
   def setup_test_formula(name, content = nil, bottle_block: nil)
     case name
     when /^testball/

Library/Homebrew/test/tap_spec.rb

@@ -210,9 +210,7 @@ describe Tap do
     setup_git_repo
 
     expect(homebrew_foo_tap.git_head).to eq("0453e16c8e3fac73104da50927a86221ca0740c2")
-    expect(homebrew_foo_tap.git_short_head).to eq("0453")
     expect(homebrew_foo_tap.git_last_commit).to match(/\A\d+ .+ ago\Z/)
-    expect(homebrew_foo_tap.git_last_commit_date).to eq("2017-01-22")
   end
 
   specify "#private?" do

completions/bash/brew

@@ -245,21 +245,6 @@ _brew___repository() {
   __brew_complete_tapped
 }
 
-_brew___version() {
-  local cur="${COMP_WORDS[COMP_CWORD]}"
-  case "$cur" in
-    -*)
-      __brewcomp "
-      --debug
-      --help
-      --quiet
-      --verbose
-      "
-      return
-      ;;
-  esac
-}
-
 _brew__s() {
   local cur="${COMP_WORDS[COMP_CWORD]}"
   case "$cur" in
@@ -287,21 +272,6 @@ _brew__s() {
   esac
 }
 
-_brew__v() {
-  local cur="${COMP_WORDS[COMP_CWORD]}"
-  case "$cur" in
-    -*)
-      __brewcomp "
-      --debug
-      --help
-      --quiet
-      --verbose
-      "
-      return
-      ;;
-  esac
-}
-
 _brew_abv() {
   local cur="${COMP_WORDS[COMP_CWORD]}"
   case "$cur" in
@@ -2316,9 +2286,7 @@ _brew() {
     --prefix) _brew___prefix ;;
     --repo) _brew___repo ;;
     --repository) _brew___repository ;;
-    --version) _brew___version ;;
     -S) _brew__s ;;
-    -v) _brew__v ;;
     abv) _brew_abv ;;
     analytics) _brew_analytics ;;
     audit) _brew_audit ;;

completions/fish/brew.fish

@@ -271,13 +271,6 @@ __fish_brew_complete_arg '--repository' -l verbose -d 'Make some output more ver
 __fish_brew_complete_arg '--repository' -a '(__fish_brew_suggest_taps_installed)'
 
 
-__fish_brew_complete_cmd '--version' 'Print the version numbers of Homebrew, Homebrew/homebrew-core and Homebrew/homebrew-cask (if tapped) to standard output'
-__fish_brew_complete_arg '--version' -l debug -d 'Display any debugging information'
-__fish_brew_complete_arg '--version' -l help -d 'Show this message'
-__fish_brew_complete_arg '--version' -l quiet -d 'Make some output more quiet'
-__fish_brew_complete_arg '--version' -l verbose -d 'Make some output more verbose'
-
-
 __fish_brew_complete_cmd '-S' 'Perform a substring search of cask tokens and formula names for text'
 __fish_brew_complete_arg '-S' -l cask -d 'Without text, list all locally available casks (including tapped ones, no online search is performed). With text, search online and locally for casks'
 __fish_brew_complete_arg '-S' -l closed -d 'Search for only closed GitHub pull requests'
@@ -297,13 +290,6 @@ __fish_brew_complete_arg '-S' -l ubuntu -d 'Search for text in the given package
 __fish_brew_complete_arg '-S' -l verbose -d 'Make some output more verbose'
 
 
-__fish_brew_complete_cmd '-v' 'Print the version numbers of Homebrew, Homebrew/homebrew-core and Homebrew/homebrew-cask (if tapped) to standard output'
-__fish_brew_complete_arg '-v' -l debug -d 'Display any debugging information'
-__fish_brew_complete_arg '-v' -l help -d 'Show this message'
-__fish_brew_complete_arg '-v' -l quiet -d 'Make some output more quiet'
-__fish_brew_complete_arg '-v' -l verbose -d 'Make some output more verbose'
-
-
 __fish_brew_complete_cmd 'abv' 'Display brief statistics for your Homebrew installation'
 __fish_brew_complete_arg 'abv' -l all -d 'Print JSON of all available formulae'
 __fish_brew_complete_arg 'abv' -l analytics -d 'List global Homebrew analytics data or, if specified, installation and build error data for formula (provided neither `HOMEBREW_NO_ANALYTICS` nor `HOMEBREW_NO_GITHUB_API` are set)'

completions/zsh/_brew

@@ -337,15 +337,6 @@ _brew___repository() {
     '::tap:__brew_any_tap'
 }
 
-# brew --version
-_brew___version() {
-  _arguments \
-    '--debug[Display any debugging information]' \
-    '--help[Show this message]' \
-    '--quiet[Make some output more quiet]' \
-    '--verbose[Make some output more verbose]'
-}
-
 # brew -S
 _brew__s() {
   _arguments \
@@ -367,15 +358,6 @@ _brew__s() {
     '--verbose[Make some output more verbose]'
 }
 
-# brew -v
-_brew__v() {
-  _arguments \
-    '--debug[Display any debugging information]' \
-    '--help[Show this message]' \
-    '--quiet[Make some output more quiet]' \
-    '--verbose[Make some output more verbose]'
-}
-
 # brew abv
 _brew_abv() {
   _arguments \

docs/Manpage.md

@@ -749,8 +749,7 @@ If *`user`*`/`*`repo`* are provided, display where tap *`user`*`/`*`repo`*'s dir
 
 ### `--version`, `-v`
 
-Print the version numbers of Homebrew, Homebrew/homebrew-core and Homebrew/homebrew-cask
-(if tapped) to standard output.
+Print the version numbers of Homebrew, Homebrew/homebrew-core and Homebrew/homebrew-cask (if tapped) to standard output.
 
 ## DEVELOPER COMMANDS