2 files changed, 113 insertions, 3 deletions
diff --git a/actionview/lib/action_view/helpers/url_helper.rb b/actionview/lib/action_view/helpers/url_helper.rb
index 4e436433c4..71fed39351 100644
--- a/actionview/lib/action_view/helpers/url_helper.rb
+++ b/actionview/lib/action_view/helpers/url_helper.rb
@@ -590,10 +590,10 @@ module ActionView
 
         def add_method_to_attributes!(html_options, method)
           if method && method.to_s.downcase != "get" && html_options["rel"] !~ /nofollow/
-            if html_options.key?("rel")
-              html_options["rel"] = "#{html_options["rel"]} nofollow".lstrip
-            else
+            if html_options.("rel").blank?
               html_options["rel"] = "nofollow"
+            else
+              html_options["rel"] = "#{html_options["rel"]} nofollow"
             end
           end
           html_options["data-method"] = method
diff --git a/test.rb b/test.rb
new file mode 100644
index 0000000000..3d5e508fa7
--- /dev/null
+++ b/test.rb
@@ -0,0 +1,110 @@
+# frozen_string_literal: true
+begin
+  require "bundler/inline"
+rescue LoadError => e
+  $stderr.puts "Bundler version 1.10 or later is required. Please update
+                your Bundler"
+  raise e
+end
+
+gemfile(true) do
+  source "https://rubygems.org"
+
+  gem "benchmark-ips"
+  gem "rails"
+end
+
+def allocate_count
+  GC.disable
+  before = ObjectSpace.count_objects
+  yield
+  after = ObjectSpace.count_objects
+  after.each { |k,v| after[k] = v - before[k] }
+  after[:T_HASH] -= 1 # probe effect - we created the before hash.
+  GC.enable
+  result = after.reject { |k,v| v == 0 }
+  GC.start
+  result
+end
+
+@hash = {}
+
+def master_version
+  "#{@hash["rel"]} nofollow".lstrip
+end
+
+def key_version
+  if @hash.key?("rel")
+    "#{@hash["rel"]} nofollow".lstrip
+  else
+    "nofollow"
+  end
+end
+
+def present_version
+  if @hash["rel"].present?
+    "#{@hash["rel"]} nofollow"
+  else
+    "nofollow".freeze
+  end
+end
+
+def nil_version
+  if @hash["rel"].nil?
+    "nofollow".freeze
+  else
+    "#{@hash["rel"]} nofollow"
+  end
+end
+
+def blank_version
+  if @hash["rel"].blank?
+    "nofollow".freeze
+  else
+    "#{@hash["rel"]} nofollow"
+  end
+end
+
+def test
+  puts "master_version"
+  puts allocate_count { 1000.times { master_version } }
+  puts "key_version"
+  puts allocate_count { 1000.times { key_version } }
+  puts "present_version"
+  puts allocate_count { 1000.times { present_version } }
+  puts "nil_version"
+  puts allocate_count { 1000.times { nil_version } }
+  puts "blank_version"
+  puts allocate_count { 1000.times { blank_version } }
+
+  Benchmark.ips do |x|
+    x.report("master_version")  { master_version }
+    x.report("key_version")     { key_version }
+    x.report("present_version") { present_version }
+    x.report("nil_version")     { nil_version }
+    x.report("blank_version")     { blank_version }
+    x.compare!
+  end
+end
+
+puts 'no rel key'
+
+test
+
+puts 'rel key with real stuff'
+
+@hash['rel'] = 'hi'.freeze
+
+test
+
+puts 'rel key with nil'
+
+@hash['rel'] = nil
+
+test
+
+puts 'rel key with ""'
+
+@hash['rel'] = ""
+
+test