1 files changed, 59 insertions, 0 deletions
diff --git a/tooling/danger/sidekiq_args.rb b/tooling/danger/sidekiq_args.rb
new file mode 100644
index 00000000000..d06bb92ca6d
--- /dev/null
+++ b/tooling/danger/sidekiq_args.rb
@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+module Tooling
+  module Danger
+    module SidekiqArgs
+      include ::Danger::Helpers
+
+      WORKER_FILES_REGEX = 'app/workers'
+      EE_PREFIX = 'ee/'
+      DEF_PERFORM = "def perform"
+      DEF_PERFORM_REGEX = /[\s+-]*def perform\((.*)\)/
+      BEFORE_DEF_PERFORM_REGEX = /^[\s-]*def perform\b/
+      AFTER_DEF_PERFORM_REGEX = /^[\s+]*def perform\b/
+
+      SUGGEST_MR_COMMENT = <<~SUGGEST_COMMENT
+        Please follow the [sidekiq development guidelines](https://docs.gitlab.com/ee/development/sidekiq/compatibility_across_updates.html#changing-the-arguments-for-a-worker) when changing sidekiq worker arguments.
+      SUGGEST_COMMENT
+
+      def changed_worker_files(ee: :include)
+        changed_files = helper.all_changed_files
+        folder_prefix =
+          case ee
+          when :include
+            "(#{EE_PREFIX})?"
+          when :only
+            EE_PREFIX
+          when :exclude
+            nil
+          end
+
+        changed_files.grep(%r{\A#{folder_prefix}#{WORKER_FILES_REGEX}})
+      end
+
+      def args_changed?(diff)
+        # Find the "before" and "after" versions of the perform method definition
+        before_def_perform = diff.find { |line| BEFORE_DEF_PERFORM_REGEX.match?(line) }
+        after_def_perform = diff.find { |line| AFTER_DEF_PERFORM_REGEX.match?(line) }
+
+        # args are not changed if there is no before or after def perform method
+        return false unless before_def_perform && after_def_perform
+
+        # Extract the perform  method arguments from the "before" and "after" versions
+        before_args, after_args = diff.flat_map { |line| line.scan(DEF_PERFORM_REGEX) }
+
+        before_args != after_args
+      end
+
+      def add_comment_for_matched_line(filename)
+        diff = helper.changed_lines(filename)
+        return unless args_changed?(diff)
+
+        file_lines = project_helper.file_lines(filename)
+
+        perform_method_line = file_lines.index { |line| line.include?(DEF_PERFORM) }
+        markdown(format(SUGGEST_MR_COMMENT), file: filename, line: perform_method_line.succ)
+      end
+    end
+  end
+end