Move gem install bundler logic into Bash.

We've been getting regular but racey errors when installing Bundler
inside Ruby. Also, it shouldn't ever be needed with Portable Ruby as
we always vendor Bundler there.

Move the relevant logic into Bash and add various fast developer-only
checks to ensure that Portable Ruby is installed correctly so we can
fix things in CI before they end up putting weird configurations onto
users.

Author: MikeMcQuaid

Library/Homebrew/Gemfile.lock

@@ -221,4 +221,4 @@ RUBY VERSION
    ruby 3.4.7p58
 
 BUNDLED WITH
-   2.6.8
+   2.6.9

Library/Homebrew/dev-cmd/vendor-gems.rb

@@ -25,10 +25,7 @@ class VendorGems < AbstractCommand
 
       sig { override.void }
       def run
-        Homebrew.install_bundler!
-
         ENV["BUNDLE_WITH"] = Homebrew.valid_gem_groups.join(":")
-        ENV["BUNDLER_VERSION"] = HOMEBREW_BUNDLER_VERSION
 
         ohai "cd #{HOMEBREW_LIBRARY_PATH}"
         HOMEBREW_LIBRARY_PATH.cd do

Library/Homebrew/standalone/init.rb

@@ -58,6 +58,9 @@ def self.from_rubylibdir(feature)
 HOMEBREW_LIBRARY_PATH = Pathname(dir).parent.realpath.freeze
 HOMEBREW_USING_PORTABLE_RUBY = RbConfig.ruby.include?("/vendor/portable-ruby/").freeze
 
+HOMEBREW_BUNDLER_VERSION = ENV.fetch("HOMEBREW_BUNDLER_VERSION").freeze
+ENV["BUNDLER_VERSION"] = HOMEBREW_BUNDLER_VERSION
+
 require_relative "../utils/gems"
 Homebrew.setup_gem_environment!(setup_path: false)
 
@@ -77,7 +80,7 @@ def self.from_rubylibdir(feature)
 require_relative "../vendor/bundle/bundler/setup"
 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"
+                   "bundler-#{HOMEBREW_BUNDLER_VERSION}/lib"
 $LOAD_PATH.uniq!
 
 # These warnings are nice but often flag problems that are not even our responsibly,

Library/Homebrew/test/rubocop_spec.rb

@@ -10,6 +10,7 @@
         allowlist = %w[
           HOMEBREW_TESTS
           HOMEBREW_USE_RUBY_FROM_PATH
+          HOMEBREW_BUNDLER_VERSION
         ]
         ENV.delete(key) if key.start_with?("HOMEBREW_") && allowlist.exclude?(key)
       end

Library/Homebrew/utils/gems.rb

@@ -8,10 +8,6 @@
 Homebrew::FastBootRequire.from_rubylibdir("English")
 
 module Homebrew
-  # Keep in sync with the `Gemfile.lock`'s BUNDLED WITH.
-  # After updating this, run `brew vendor-gems --update=--bundler`.
-  HOMEBREW_BUNDLER_VERSION = "2.6.8" # Pinned to <2.6.9 until Ruby 3.5.
-
   # Bump this whenever a committed vendored gem is later added to or exclusion removed from gitignore.
   # This will trigger it to reinstall properly if `brew install-bundler-gems` needs it.
   VENDOR_VERSION = 7
@@ -41,7 +37,6 @@ def self.bundler_definition
   private_class_method :bundler_definition
 
   def self.valid_gem_groups
-    install_bundler!
     require "bundler"
 
     Bundler.with_unbundled_env do
@@ -161,22 +156,6 @@ def self.find_in_path(executable)
   end
   private_class_method :find_in_path
 
-  def self.install_bundler!
-    old_bundler_version = ENV.fetch("BUNDLER_VERSION", nil)
-
-    setup_gem_environment!
-
-    ENV["BUNDLER_VERSION"] = HOMEBREW_BUNDLER_VERSION # Set so it correctly finds existing installs
-    install_gem_setup_path!(
-      "bundler",
-      version:               HOMEBREW_BUNDLER_VERSION,
-      executable:            "bundle",
-      setup_gem_environment: false,
-    )
-  ensure
-    ENV["BUNDLER_VERSION"] = old_bundler_version
-  end
-
   def self.user_gem_groups
     @user_gem_groups ||= if GEM_GROUPS_FILE.exist?
       GEM_GROUPS_FILE.readlines(chomp: true)
@@ -241,8 +220,6 @@ def self.install_bundler_gems!(only_warn_on_failure: false, setup_path: true, gr
       return
     end
 
-    install_bundler!
-
     # Combine the passed groups with the ones stored in settings.
     groups |= (user_gem_groups & valid_gem_groups)
     groups.sort!

Library/Homebrew/utils/ruby.sh

@@ -4,6 +4,7 @@
 # shellcheck disable=SC2154
 export HOMEBREW_REQUIRED_RUBY_VERSION="3.4"
 HOMEBREW_PORTABLE_RUBY_VERSION="$(cat "${HOMEBREW_LIBRARY}/Homebrew/vendor/portable-ruby-version")"
+export HOMEBREW_BUNDLER_VERSION="2.6.9"
 
 # Disable Ruby options we don't need.
 export HOMEBREW_RUBY_DISABLE_OPTIONS="--disable=gems,rubyopt"
@@ -150,9 +151,30 @@ If there's no Homebrew Portable Ruby available for your processor:
       brew vendor-install ruby || odie "${install_fail}"
       HOMEBREW_RUBY_PATH="${vendor_ruby_path}"
       TERMINFO_DIRS="${vendor_ruby_terminfo}"
+
+      if [[ -n "${HOMEBREW_DEVELOPER}" && -x "${vendor_ruby_path}" ]]
+      then
+        if [[ ! -f "${vendor_ruby_root}/bin/bundle" ]]
+        then
+          odie "Homebrew Portable Ruby is installed but bundle is not!"
+        elif [[ ! -d "${vendor_ruby_root}/lib/ruby/gems/${HOMEBREW_REQUIRED_RUBY_VERSION}.0/gems/bundler-${HOMEBREW_BUNDLER_VERSION}" ]]
+        then
+          odie "Homebrew Portable Ruby is installed but bundler ${HOMEBREW_BUNDLER_VERSION} is not!"
+        elif ! grep -q "  ${HOMEBREW_BUNDLER_VERSION}" "${HOMEBREW_LIBRARY}/Homebrew/Gemfile.lock"
+        then
+          odie "Homebrew Portable Ruby is installed but bundler ${HOMEBREW_BUNDLER_VERSION} is not in the Gemfile.lock!"
+        fi
+      fi
     fi
   fi
 
+  homebrew_ruby_bin="$(dirname "${HOMEBREW_RUBY_PATH}")"
+  if [[ ! -f "${homebrew_ruby_bin}/bundle" ]]
+  then
+    "${homebrew_ruby_bin}/gem" install bundler -v "${HOMEBREW_BUNDLER_VERSION}"
+  fi
+  PATH="${homebrew_ruby_bin}:${PATH}"
+
   export HOMEBREW_RUBY_PATH HOMEBREW_BOOTSNAP_GEM_PATH
   [[ -n "${HOMEBREW_LINUX}" && -n "${TERMINFO_DIRS}" ]] && export TERMINFO_DIRS
 }