Use fullpath from Rack request rather than building it

In Rack, `#fullpath` checks if there is a query string and builds the
query correctly:

```
def path
  script_name + path_info
end

def fullpath
  query_string.empty? ? path : "#{path}?#{query_string}"
end
```

We can utilize this instead of manually building the fullpath because
they are the same result. This also reduces allocations in `#call`
because we don't need `build_original_fullpath` to create the paths and
query strings. We don't need to build `fullpath` twice.

1 files changed, 5 insertions, 11 deletions

diff --git a/railties/lib/rails/application.rb b/railties/lib/rails/application.rb
index ff6c905f3e..ad6ec1264d 100644
--- a/railties/lib/rails/application.rb
+++ b/railties/lib/rails/application.rb
@@ -159,8 +159,9 @@ module Rails
     # Implements call according to the Rack API. It simply
     # dispatches the request to the underlying middleware stack.
     def call(env)
-      env["ORIGINAL_FULLPATH"] = build_original_fullpath(env)
-      env["ORIGINAL_SCRIPT_NAME"] = env["SCRIPT_NAME"]
+      req = ActionDispatch::Request.new env
+      env["ORIGINAL_FULLPATH"] = req.fullpath
+      env["ORIGINAL_SCRIPT_NAME"] = req.script_name
       super(env)
     end
 
@@ -505,15 +506,8 @@ module Rails
     end
 
     def build_original_fullpath(env) #:nodoc:
-      path_info    = env["PATH_INFO"]
-      query_string = env["QUERY_STRING"]
-      script_name  = env["SCRIPT_NAME"]
-
-      if query_string.present?
-        "#{script_name}#{path_info}?#{query_string}"
-      else
-        "#{script_name}#{path_info}"
-      end
+      req = ActionDispatch::Request.new env
+      env["ORIGINAL_FULLPATH"] = req.fullpath
     end
 
     def validate_secret_key_config! #:nodoc: