Merge pull request #21241 from pdg137/master

In url_for, never append ? when the query string is empty anyway.

actionpack/CHANGELOG.md

@@ -1,3 +1,7 @@
+*   In url_for, never append a question mark to the URL when the query string
+    is empty anyway.  (It used to do that when called like `url_for(controller:
+    'x', action: 'y', q: {})`.)
+
 *   Catch invalid UTF-8 querystring values and respond with BadRequest
 
     Check querystring params for invalid UTF-8 characters, and raise an

actionpack/lib/action_dispatch/http/url.rb

@@ -81,7 +81,8 @@ module ActionDispatch
         def add_params(path, params)
           params = { params: params } unless params.is_a?(Hash)
           params.reject! { |_,v| v.to_param.nil? }
-          path << "?#{params.to_query}" unless params.empty?
+          query = params.to_query
+          path << "?#{query}" unless query.empty?
         end
 
         def add_anchor(path, anchor)

actionpack/test/dispatch/url_generation_test.rb

@@ -129,6 +129,13 @@ module TestUrlGeneration
       )
     end
 
+    test "generating URLS with empty querystring" do
+      assert_equal "/bars.json", bars_path(
+        a: {},
+        format: 'json'
+      )
+    end
+
   end
 end
 

actionview/test/template/url_helper_test.rb

@@ -38,6 +38,10 @@ class UrlHelperTest < ActiveSupport::TestCase
     assert_equal "/?a=b&c=d", url_for(hash_for(a: :b, c: :d))
   end
 
+  def test_url_for_does_not_include_empty_hashes
+    assert_equal "/", url_for(hash_for(a: {}))
+  end
+
   def test_url_for_with_back
     referer = 'http://www.example.com/referer'
     @controller = Struct.new(:request).new(Struct.new(:env).new("HTTP_REFERER" => referer))