1 files changed, 43 insertions, 0 deletions
diff --git a/tooling/danger/config_files.rb b/tooling/danger/config_files.rb
new file mode 100644
index 00000000000..436335bfc06
--- /dev/null
+++ b/tooling/danger/config_files.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+require 'yaml'
+
+module Tooling
+  module Danger
+    module ConfigFiles
+      SUGGEST_INTRODUCED_BY_COMMENT = <<~SUGGEST_COMMENT
+        ```suggestion
+        introduced_by_url: "%<url>s"
+        ```
+      SUGGEST_COMMENT
+
+      CONFIG_DIRS = %w[
+        config/feature_flags
+        config/metrics
+        config/events
+      ].freeze
+
+      def add_suggestion_for_missing_introduced_by_url
+        new_config_files.each do |file_name|
+          config_file_lines = project_helper.file_lines(file_name)
+
+          config_file_lines.each_with_index do |added_line, i|
+            next unless added_line =~ /^introduced_by_url:\s?$/
+
+            markdown(format(SUGGEST_INTRODUCED_BY_COMMENT, url: helper.mr_web_url), file: file_name, line: i + 1)
+          end
+        end
+      end
+
+      def new_config_files
+        helper.added_files.select { |f| in_config_dir?(f) && f.end_with?('yml') }
+      end
+
+      private
+
+      def in_config_dir?(path)
+        CONFIG_DIRS.any? { |d| path.start_with?(d) }
+      end
+    end
+  end
+end