Add autocorrect to Rails/LinkToBlank (#6604)

Author: Adrien S

lib/rubocop/cop/rails/link_to_blank.rb

@@ -25,6 +25,10 @@ class LinkToBlank < Cop
           (pair {(sym :rel) (str "rel")} (str #contains_noopener?))
         PATTERN
 
+        def_node_matcher :rel_node?, <<-PATTERN
+          (pair {(sym :rel) (str "rel")} (str _))
+        PATTERN
+
         def on_send(node)
           return unless node.method?(:link_to)
 
@@ -38,8 +42,41 @@ def on_send(node)
           end
         end
 
+        def autocorrect(node)
+          lambda do |corrector|
+            send_node = node.parent.parent
+
+            option_nodes = send_node.each_child_node(:hash)
+            rel_node = nil
+            option_nodes.map(&:children).each do |options|
+              rel_node ||= options.find { |o| rel_node?(o) }
+            end
+
+            if rel_node
+              append_to_rel(rel_node, corrector)
+            else
+              add_rel(send_node, node, corrector)
+            end
+          end
+        end
+
         private
 
+        def append_to_rel(rel_node, corrector)
+          existing_rel = rel_node.children.last.value
+          str_range = rel_node.children.last.loc.expression.adjust(
+            begin_pos: 1,
+            end_pos: -1
+          )
+          corrector.replace(str_range, "#{existing_rel} noopener")
+        end
+
+        def add_rel(send_node, offence_node, corrector)
+          quote_style = offence_node.children.last.source[0]
+          new_rel_exp = ", rel: #{quote_style}noopener#{quote_style}"
+          corrector.insert_after(send_node.loc.expression, new_rel_exp)
+        end
+
         def contains_noopener?(str)
           return false unless str
 

manual/cops_rails.md

@@ -1183,7 +1183,7 @@ Include | `app/controllers/**/*.rb` | Array
 
 Enabled by default | Supports autocorrection
 --- | ---
-Enabled | No
+Enabled | Yes
 
 This cop checks for calls to `link_to` that contain a
 `target: '_blank'` but no `rel: 'noopener'`. This can be a security

spec/rubocop/cop/rails/link_to_blank_spec.rb

@@ -34,6 +34,15 @@
         RUBY
       end
 
+      it 'autocorrects with a new rel' do
+        new_source = autocorrect_source(<<-RUBY.strip_indent)
+          link_to 'Click here', 'https://www.example.com', target: '_blank'
+        RUBY
+        expect(new_source).to eq(<<-RUBY.strip_indent)
+          link_to 'Click here', 'https://www.example.com', target: '_blank', rel: 'noopener'
+        RUBY
+      end
+
       it 'registers an offence when using a string for the target key' do
         expect_offense(<<-RUBY.strip_indent)
           link_to 'Click here', 'https://www.example.com', "target" => '_blank'
@@ -49,6 +58,19 @@
           end
         RUBY
       end
+
+      it 'autocorrects with a new rel when using the block syntax' do
+        new_source = autocorrect_source(<<-RUBY.strip_indent)
+          link_to 'https://www.example.com', target: '_blank' do
+            "Click here"
+          end
+        RUBY
+        expect(new_source).to eq(<<-RUBY.strip_indent)
+          link_to 'https://www.example.com', target: '_blank', rel: 'noopener' do
+            "Click here"
+          end
+        RUBY
+      end
     end
 
     context 'when using rel' do
@@ -59,6 +81,15 @@
                                                              ^^^^^^^^^^^^^^^^^^^^ Specify a `:rel` option containing noopener.
           RUBY
         end
+
+        it 'autocorrects by appending to the existing rel' do
+          new_source = autocorrect_source(<<-RUBY.strip_indent)
+            link_to 'Click here', 'https://www.example.com', target: '_blank', rel: 'foo'
+          RUBY
+          expect(new_source).to eq(<<-RUBY.strip_indent)
+            link_to 'Click here', 'https://www.example.com', target: '_blank', rel: 'foo noopener'
+          RUBY
+        end
       end
 
       context 'when the rel contains noopener' do