Cache commands list for faster shell completions

Library/Homebrew/brew.sh

@@ -233,6 +233,10 @@ HOMEBREW_CACHE="${HOMEBREW_CACHE:-${HOMEBREW_DEFAULT_CACHE}}"
 HOMEBREW_LOGS="${HOMEBREW_LOGS:-${HOMEBREW_DEFAULT_LOGS}}"
 HOMEBREW_TEMP="${HOMEBREW_TEMP:-${HOMEBREW_DEFAULT_TEMP}}"
 
+case "$*" in
+  --cache)             echo "$HOMEBREW_CACHE"; exit 0 ;;
+esac
+
 HOMEBREW_USER_AGENT="$HOMEBREW_PRODUCT/$HOMEBREW_USER_AGENT_VERSION ($HOMEBREW_SYSTEM; $HOMEBREW_PROCESSOR $HOMEBREW_OS_USER_AGENT_VERSION)"
 curl_version_output="$("$HOMEBREW_CURL" --version 2>/dev/null)"
 curl_name_and_version="${curl_version_output%% (*}"

Library/Homebrew/cmd/update-report.rb

@@ -129,6 +129,7 @@ module Homebrew
       puts if args.preinstall?
     end
 
+    Commands.rebuild_commands_completion_list
     link_completions_manpages_and_docs
     Tap.each(&:link_completions_and_manpages)
   end

Library/Homebrew/cmd/update.sh

@@ -604,6 +604,7 @@ EOS
         -n "$HOMEBREW_UPDATE_FAILED" ||
         -n "$HOMEBREW_UPDATE_FORCE" ||
         -d "$HOMEBREW_LIBRARY/LinkedKegs" ||
+        ! -f "$HOMEBREW_CACHE/all_commands_list.txt" ||
         (-n "$HOMEBREW_DEVELOPER" && -z "$HOMEBREW_UPDATE_PREINSTALL") ]]
   then
     brew update-report "$@"

Library/Homebrew/commands.rb

@@ -143,4 +143,21 @@ module Commands
             .select(&:file?)
             .sort
   end
+
+  def rebuild_internal_commands_completion_list
+    cmds = internal_commands + internal_developer_commands + internal_commands_aliases
+
+    file = HOMEBREW_REPOSITORY/"completions/internal_commands_list.txt"
+    file.delete if file.exist?
+    file.write(cmds.sort.join("\n") + "\n")
+  end
+
+  def rebuild_commands_completion_list
+    # Ensure that the cache exists so we can build the commands list
+    HOMEBREW_CACHE.mkpath
+
+    file = HOMEBREW_CACHE/"all_commands_list.txt"
+    file.delete if file.exist?
+    file.write(commands(aliases: true).sort.join("\n") + "\n")
+  end
 end

Library/Homebrew/dev-cmd/man.rb

@@ -35,10 +35,11 @@ module Homebrew
 
     odie "`brew man --link` is now done automatically by `brew update`." if args.link?
 
+    Commands.rebuild_internal_commands_completion_list
     regenerate_man_pages
 
-    if system "git", "-C", HOMEBREW_REPOSITORY, "diff", "--quiet", "docs/Manpage.md", "manpages"
+    if system "git", "-C", HOMEBREW_REPOSITORY, "diff", "--quiet", "docs/Manpage.md", "manpages", "completions"
-      puts "No changes to manpage output detected."
+      puts "No changes to manpage or completions output detected."
     elsif args.fail_if_changed?
       Homebrew.failed = true
     end

Library/Homebrew/tap.rb

@@ -286,6 +286,7 @@ class Tap
 
     config["forceautoupdate"] = force_auto_update unless force_auto_update.nil?
 
+    Commands.rebuild_commands_completion_list
     link_completions_and_manpages
 
     formatted_contents = contents.presence&.to_sentence&.dup&.prepend(" ")
@@ -334,6 +335,8 @@ class Tap
     path.rmtree
     path.parent.rmdir_if_possible
     puts "Untapped#{formatted_contents} (#{abv})."
+
+    Commands.rebuild_commands_completion_list
     clear_cache
   end
 

completions/internal_commands_list.txt

@@ -0,0 +1,95 @@
+--cache
+--cellar
+--config
+--env
+--prefix
+--repo
+--repository
+--version
+-S
+-v
+abv
+analytics
+audit
+bottle
+bump-formula-pr
+bump-revision
+cask
+cat
+cleanup
+command
+commands
+config
+configure
+create
+deps
+desc
+diy
+doctor
+dr
+edit
+environment
+extract
+fetch
+formula
+gist-logs
+help
+home
+homepage
+info
+instal
+install
+install-bundler-gems
+irb
+leaves
+link
+linkage
+list
+ln
+log
+ls
+man
+migrate
+mirror
+missing
+options
+outdated
+pin
+postinstall
+pr-automerge
+pr-publish
+pr-pull
+pr-upload
+prof
+pull
+readall
+reinstall
+release-notes
+remove
+rm
+ruby
+search
+sh
+shellenv
+style
+switch
+tap
+tap-info
+tap-new
+test
+tests
+uninstal
+uninstall
+unlink
+unpack
+unpin
+untap
+up
+update
+update-report
+update-reset
+update-test
+upgrade
+uses
+vendor-gems
+vendor-install

completions/zsh/_brew

@@ -148,7 +148,11 @@ __brew_all_commands() {
   local -a commands
   local comp_cachename=brew_all_commands
   if _cache_invalid $comp_cachename || ! _retrieve_cache $comp_cachename; then
-    commands=($(_call_program brew brew commands --quiet --include-aliases))
+    HOMEBREW_CACHE=$(brew --cache)
+    HOMEBREW_REPOSITORY=$(brew --repo)
+    [[ -f "$HOMEBREW_CACHE/all_commands_list.txt" ]] &&
+      commands=($(cat "$HOMEBREW_CACHE/all_commands_list.txt")) ||
+      commands=($(cat "$HOMEBREW_REPOSITORY/completions/internal_commands_list.txt"))
     commands=(${commands:#*instal}) # Exclude instal, uninstal, etc.
     _store_cache $comp_cachename commands
   fi