Persist glob when replacing a path

When Rails::Paths::Root's []= is used to replace a path it should persist the previous path's glob. Without passing the glob along we get gnarly bugs when trying to wire up things like engines.

    module FooEngine
      class Engine < ::Rails::Engine
        isolate_namespace FooEngine

        config.paths['config/initializers'] = "lib/foo_engine/initializers"
      end
    end

    ## Example of behaviour before this commit.
    #
    # Before the initializer override:
    >> FooEngine::Engine.config.paths["config/initializers"].glob
    => "**/*.rb"

    # After the initializer override:
    >> FooEngine::Engine.config.paths["config/initializers"].glob
    => nil

    ## Example of behaviour after this commit.
    #
    # Before the initializer override:
    >> FooEngine::Engine.config.paths["config/initializers"].glob
    => "**/*.rb"

    # After the initializer override:
    >> FooEngine::Engine.config.paths["config/initializers"].glob
    => "**/*.rb"

1 files changed, 7 insertions, 0 deletions

diff --git a/railties/test/paths_test.rb b/railties/test/paths_test.rb
index 5d6b6f9f72..2b38f0975d 100644
--- a/railties/test/paths_test.rb
+++ b/railties/test/paths_test.rb
@@ -200,6 +200,13 @@ class PathsTest < ActiveSupport::TestCase
     assert_equal "*.rb", @root["app"].glob
   end
 
+  test "it should be possible to replace a path and persist the original paths glob" do
+    @root.add "app", :glob => "*.rb"
+    @root["app"] = "app2"
+    assert_equal ["/foo/bar/app2"], @root["app"].paths
+    assert_equal "*.rb", @root["app"].glob
+  end
+
   test "a path can be added to the load path" do
     @root["app"] = "app"
     @root["app"].load_path!