Add cop prohibiting params argument in url_for

1 files changed, 34 insertions, 0 deletions

diff --git a/rubocop/cop/safe_params.rb b/rubocop/cop/safe_params.rb
new file mode 100644
index 00000000000..250c16232e4
--- /dev/null
+++ b/rubocop/cop/safe_params.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+module RuboCop
+  module Cop
+    class SafeParams < RuboCop::Cop::Cop
+      MSG = 'Use `safe_params` instead of `params` in url_for.'.freeze
+
+      METHOD_NAME_PATTERN = :url_for
+      UNSAFE_PARAM = :params
+
+      def on_send(node)
+        return unless method_name(node) == METHOD_NAME_PATTERN
+
+        add_offense(node, location: :expression) unless safe_params?(node)
+      end
+
+      private
+
+      def safe_params?(node)
+        node.descendants.each do |param_node|
+          next unless param_node.descendants.empty?
+
+          return false if method_name(param_node) == UNSAFE_PARAM
+        end
+
+        true
+      end
+
+      def method_name(node)
+        node.children[1]
+      end
+    end
+  end
+end