Enable Bootsnap by default

- do some optimisation of `require`s before Bootsnap
- remove `HOMEBREW_BOOTSTRAP` environment variable as it's set by
  default
- add fast require in `bootsnap.rb` using logic from `ruby.sh`
- cleanup `bootsnap.rb` a bit
- remove setting `HOMEBREW_BOOTSNAP` in GitHub Actions

.github/workflows/docs.yml

@@ -12,7 +12,6 @@ env:
   HOMEBREW_DEVELOPER: 1
   HOMEBREW_NO_AUTO_UPDATE: 1
   HOMEBREW_NO_ENV_HINTS: 1
-  HOMEBREW_BOOTSNAP: 1
   HOMEBREW_NO_INSTALL_CLEANUP: 1
 
 defaults:

.github/workflows/rubydoc.yml

@@ -13,7 +13,6 @@ env:
   HOMEBREW_DEVELOPER: 1
   HOMEBREW_NO_AUTO_UPDATE: 1
   HOMEBREW_NO_ENV_HINTS: 1
-  HOMEBREW_BOOTSNAP: 1
   HOMEBREW_NO_INSTALL_CLEANUP: 1
 
 defaults:

.github/workflows/tests.yml

@@ -14,7 +14,6 @@ env:
   HOMEBREW_DEVELOPER: 1
   HOMEBREW_NO_AUTO_UPDATE: 1
   HOMEBREW_NO_ENV_HINTS: 1
-  HOMEBREW_BOOTSNAP: 1
   HOMEBREW_NO_INSTALL_CLEANUP: 1
   HOMEBREW_VERIFY_ATTESTATIONS: 1
 

Library/Homebrew/env_config.rb

@@ -72,11 +72,6 @@ module Homebrew
         description:  "Use this as the `bat` theme for syntax highlighting.",
         default_text: "`$BAT_THEME`.",
       },
-      HOMEBREW_BOOTSNAP:                         {
-        description: "If set, use Bootsnap to speed up repeated `brew` calls. " \
-                     "A no-op on Linux when not using Homebrew's vendored, relocatable Ruby.",
-        boolean:     true,
-      },
       HOMEBREW_BOTTLE_DOMAIN:                    {
         description:  "Use this URL as the download mirror for bottles. " \
                       "If bottles at that URL are temporarily unavailable, " \

Library/Homebrew/sorbet/rbi/dsl/homebrew/env_config.rbi

@@ -43,9 +43,6 @@ module Homebrew::EnvConfig
     sig { returns(T.nilable(::String)) }
     def bat_theme; end
 
-    sig { returns(T::Boolean) }
-    def bootsnap?; end
-
     sig { returns(String) }
     def bottle_domain; end
 

Library/Homebrew/standalone/init.rb

@@ -1,7 +1,10 @@
 # typed: true
 # frozen_string_literal: true
 
-# This file is included before any other files. It intentionally has typing disabled and has minimal use of `require`.
+# This file is included before any other files.
+# It intentionally has typing disabled and uses `Homebrew::FastBootRequire`
+# or `require_relative` to load all files
+# (except "rbconfig" which is needed by `Homebrew::FastBootRequire`)
 
 required_ruby_major, required_ruby_minor, = ENV.fetch("HOMEBREW_REQUIRED_RUBY_VERSION", "").split(".").map(&:to_i)
 gems_vendored = if required_ruby_minor.nil?
@@ -21,12 +24,30 @@ else
   vendored_versions.include?("#{ruby_major}.#{ruby_minor}")
 end.freeze
 
+# Setup Homebrew::FastBootRequire for faster boot requires.
+# Inspired by https://github.com/Shopify/bootsnap/wiki/Bootlib::Require
+require "rbconfig"
+
+module Homebrew
+  module FastBootRequire
+    ARCHDIR    = RbConfig::CONFIG["archdir"].freeze
+    RUBYLIBDIR = RbConfig::CONFIG["rubylibdir"].freeze
+
+    def self.from_archdir(feature)
+      require(File.join(ARCHDIR, feature.to_s))
+    end
+
+    def self.from_rubylibdir(feature)
+      require(File.join(RUBYLIBDIR, "#{feature}.rb"))
+    end
+  end
+end
+
 # We trust base Ruby to provide what we need.
 # Don't look into the user-installed sitedir, which may contain older versions of RubyGems.
-require "rbconfig"
 $LOAD_PATH.reject! { |path| path.start_with?(RbConfig::CONFIG["sitedir"]) }
 
-require "pathname"
+Homebrew::FastBootRequire.from_rubylibdir("pathname")
 dir = __dir__ || raise("__dir__ is not defined")
 HOMEBREW_LIBRARY_PATH = Pathname(dir).parent.realpath.freeze
 HOMEBREW_USING_PORTABLE_RUBY = RbConfig.ruby.include?("/vendor/portable-ruby/").freeze
@@ -48,7 +69,7 @@ unless $LOAD_PATH.include?(HOMEBREW_LIBRARY_PATH.to_s)
   $LOAD_PATH.insert(last_homebrew_path_idx + 1, HOMEBREW_LIBRARY_PATH.to_s)
 end
 require_relative "../vendor/bundle/bundler/setup"
-require "portable_ruby_gems" if HOMEBREW_USING_PORTABLE_RUBY
+Homebrew::FastBootRequire.from_archdir("portable_ruby_gems") if HOMEBREW_USING_PORTABLE_RUBY
 $LOAD_PATH.unshift "#{HOMEBREW_LIBRARY_PATH}/vendor/bundle/#{RUBY_ENGINE}/#{Gem.ruby_api_version}/gems/" \
                    "bundler-#{Homebrew::HOMEBREW_BUNDLER_VERSION}/lib"
 $LOAD_PATH.uniq!

Library/Homebrew/startup.rb

@@ -2,9 +2,10 @@
 # frozen_string_literal: true
 
 # This file should be the first `require` in all entrypoints of `brew`.
+# Bootsnap should be loaded as early as possible.
 
 require_relative "standalone/init"
+require_relative "startup/bootsnap"
 require_relative "startup/ruby_path"
 require "startup/config"
-require_relative "startup/bootsnap"
 require_relative "standalone/sorbet"

Library/Homebrew/startup/bootsnap.rb

@@ -34,17 +34,21 @@ module Homebrew
     end
 
     private_class_method def self.enabled?
-      HOMEBREW_USING_PORTABLE_RUBY && ENV["HOMEBREW_NO_BOOTSNAP"].nil? && !ENV["HOMEBREW_BOOTSNAP"].nil?
+      !ENV["HOMEBREW_BOOTSNAP_GEM_PATH"].to_s.empty? && ENV["HOMEBREW_NO_BOOTSNAP"].nil?
     end
 
     def self.load!(compile_cache: true)
       return unless enabled?
 
-      require "bootsnap"
+      require ENV.fetch("HOMEBREW_BOOTSNAP_GEM_PATH")
 
       ::Bootsnap.setup(
         cache_dir:,
         ignore_directories:,
+        # In development environments the bootsnap compilation cache is
+        # generated on the fly when source files are loaded.
+        # https://github.com/Shopify/bootsnap?tab=readme-ov-file#precompilation
+        development_mode:   true,
         load_path_cache:    true,
         compile_cache_iseq: compile_cache,
         compile_cache_yaml: compile_cache,

Library/Homebrew/utils/gems.rb

@@ -5,7 +5,7 @@
 # work as the first item in `brew.rb` so we can load gems with Bundler when
 # needed before anything else is loaded (e.g. `json`).
 
-require "English"
+Homebrew::FastBootRequire.from_rubylibdir("English")
 
 module Homebrew
   # Keep in sync with the `Gemfile.lock`'s BUNDLED WITH.

Library/Homebrew/utils/ruby.sh

@@ -127,6 +127,10 @@ If there's no Homebrew Portable Ruby available for your processor:
   if [[ -x "${vendor_ruby_path}" ]]
   then
     HOMEBREW_RUBY_PATH="${vendor_ruby_path}"
+    HOMEBREW_BOOTSNAP_GEM_PATH="$(
+      shopt -s nullglob
+      echo "${vendor_ruby_root}"/lib/ruby/gems/*/gems/bootsnap-*/lib/bootsnap 2>/dev/null
+    )"
     TERMINFO_DIRS="${vendor_ruby_terminfo}"
     if [[ "${vendor_ruby_current_version}" != "${HOMEBREW_PORTABLE_RUBY_VERSION}" ]]
     then
@@ -146,7 +150,7 @@ If there's no Homebrew Portable Ruby available for your processor:
     fi
   fi
 
-  export HOMEBREW_RUBY_PATH
+  export HOMEBREW_RUBY_PATH HOMEBREW_BOOTSNAP_GEM_PATH
   [[ -n "${HOMEBREW_LINUX}" && -n "${TERMINFO_DIRS}" ]] && export TERMINFO_DIRS
 }
 

docs/Manpage.md

@@ -3843,11 +3843,6 @@ command execution e.g. `$(cat file)`.
   
   *Default:* `$BAT_THEME`.
 
-`HOMEBREW_BOOTSNAP`
-
-: If set, use Bootsnap to speed up repeated `brew` calls. A no-op on Linux when
-  not using Homebrew's vendored, relocatable Ruby.
-
 `HOMEBREW_BOTTLE_DOMAIN`
 
 : Use this URL as the download mirror for bottles. If bottles at that URL are

manpages/brew.1

@@ -2473,9 +2473,6 @@ Use this as the \fBbat\fP theme for syntax highlighting\.
 \fIDefault:\fP \fB$BAT_THEME\fP\&\.
 .RE
 .TP
-\fBHOMEBREW_BOOTSNAP\fP
-If set, use Bootsnap to speed up repeated \fBbrew\fP calls\. A no\-op on Linux when not using Homebrew\[u2019]s vendored, relocatable Ruby\.
-.TP
 \fBHOMEBREW_BOTTLE_DOMAIN\fP
 Use this URL as the download mirror for bottles\. If bottles at that URL are temporarily unavailable, the default bottle domain will be used as a fallback mirror\. For example, \fBexport HOMEBREW_BOTTLE_DOMAIN=http://localhost:8080\fP will cause all bottles to download from the prefix \fBhttp://localhost:8080/\fP\&\. If bottles are not available at \fB$HOMEBREW_BOTTLE_DOMAIN\fP they will be downloaded from the default bottle domain\.
 .RS