Set the root_path to RAILS_ROOT and canonicalize it.
# File railties/lib/initializer.rb, line 532 def set_root_path! raise 'RAILS_ROOT is not set' unless defined?(::RAILS_ROOT) raise 'RAILS_ROOT is not a directory' unless File.directory?(::RAILS_ROOT) @root_path = # Pathname is incompatible with Windows, but Windows doesn't have # real symlinks so File.expand_path is safe. if RUBY_PLATFORM =~ /(:?mswin|mingw)/ File.expand_path(::RAILS_ROOT) # Otherwise use Pathname#realpath which respects symlinks. else Pathname.new(::RAILS_ROOT).realpath.to_s end end