Define ActiveSupport#to_param as to_str - closes rails#1663

actionpack/test/template/url_helper_test.rb

@@ -15,6 +15,7 @@ class UrlHelperTest < ActiveSupport::TestCase
   routes.draw do
     match "/" => "foo#bar"
     match "/other" => "foo#other"
+    match "/article/:id" => "foo#article", :as => :article
   end
 
   include routes.url_helpers
@@ -264,6 +265,13 @@ def test_link_tag_using_block_in_erb
     assert_equal '<a href="/">Example site</a>', out
   end
 
+  def test_link_tag_with_html_safe_string
+    assert_dom_equal(
+      "<a href=\"/article/Gerd_M%C3%BCller\">Gerd Müller</a>",
+      link_to("Gerd Müller", article_path("Gerd_Müller".html_safe))
+    )
+  end
+
   def test_link_to_unless
     assert_equal "Showing", link_to_unless(true, "Showing", url_hash)
 

activesupport/lib/active_support/core_ext/string/output_safety.rb

@@ -103,6 +103,10 @@ def to_s
       self
     end
 
+    def to_param
+      to_str
+    end
+
     def encode_with(coder)
       coder.represent_scalar nil, to_str
     end

activesupport/test/core_ext/string_ext_test.rb

@@ -251,7 +251,7 @@ def test_string_squish
     # And changes the original string:
     assert_equal original, expected
   end
-  
+
   def test_string_inquiry
     assert "production".inquiry.production?
     assert !"production".inquiry.development?
@@ -451,6 +451,12 @@ def to_s
       assert !'ruby'.encoding_aware?
     end
   end
+
+  test "call to_param returns a normal string" do
+    string = @string.html_safe
+    assert string.html_safe?
+    assert !string.to_param.html_safe?
+  end
 end
 
 class StringExcludeTest < ActiveSupport::TestCase