Prevent require executing some scripts

Library/Homebrew/brew.rb

@@ -7,6 +7,7 @@ if ENV["HOMEBREW_STACKPROF"]
 end
 
 raise "HOMEBREW_BREW_FILE was not exported! Please call bin/brew directly!" unless ENV["HOMEBREW_BREW_FILE"]
+raise "#{__FILE__} must not be loaded via `require`." if $PROGRAM_NAME != __FILE__
 
 std_trap = trap("INT") { exit! 130 } # no backtrace thanks
 

Library/Homebrew/build.rb

@@ -4,6 +4,8 @@
 # This script is loaded by formula_installer as a separate instance.
 # Thrown exceptions are propagated back to the parent process over a pipe
 
+raise "#{__FILE__} must not be loaded via `require`." if $PROGRAM_NAME != __FILE__
+
 old_trap = trap("INT") { exit! 130 }
 
 require_relative "global"

Library/Homebrew/postinstall.rb

@@ -1,6 +1,8 @@
 # typed: strict
 # frozen_string_literal: true
 
+raise "#{__FILE__} must not be loaded via `require`." if $PROGRAM_NAME != __FILE__
+
 old_trap = trap("INT") { exit! 130 }
 
 require_relative "global"

Library/Homebrew/test.rb

@@ -1,6 +1,8 @@
 # typed: false
 # frozen_string_literal: true
 
+raise "#{__FILE__} must not be loaded via `require`." if $PROGRAM_NAME != __FILE__
+
 old_trap = trap("INT") { exit! 130 }
 
 require_relative "global"