Add AlphabeticalSerializerAttributes

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    rubocop-teamtailor (0.2.0)
+    rubocop-teamtailor (0.3.0)
       rubocop
 
 GEM

config/default.yml

@@ -1,5 +1,12 @@
 # Write it!
 
+Teamtailor/AlphabeticalSerializerAttributes:
+  Description: "Serializer attributes should be in alphabetical order."
+  Enabled: true
+  Include:
+    - "app/serializers/**/*.rb"
+  VersionAdded: "<<next>>"
+
 Teamtailor/NoEmbeddingsInActiveModelSerializer:
   Description: "TODO: Write a description of the cop."
   Enabled: true

lib/rubocop/cop/teamtailor/alphabetical_serializer_attributes.rb

@@ -0,0 +1,112 @@
+# frozen_string_literal: true
+
+module RuboCop
+  module Cop
+    module Teamtailor
+      class AlphabeticalSerializerAttributes < Base
+        extend AutoCorrector
+
+        MSG = "Serializer attributes should be in alphabetical order (symbols first, then hashes)"
+        RESTRICT_ON_SEND = %i[attributes serializer_attributes].freeze
+
+        def on_send(node)
+          return unless node.arguments.any?
+          return unless in_serializer_class?(node)
+
+          args = node.arguments
+          sorted_args = sort_arguments(args)
+          return if args_match?(args, sorted_args)
+
+          add_offense(node) do |corrector|
+            corrector.replace(arguments_range(node), format_arguments(sorted_args, node))
+          end
+        end
+
+        private
+
+        def in_serializer_class?(node)
+          node.each_ancestor(:class).any? do |class_node|
+            class_node.defined_module_name&.end_with?("Serializer")
+          end
+        end
+
+        def sort_arguments(args)
+          symbols = []
+          splats = []
+          others = []
+          hash_items = []
+
+          args.each do |arg|
+            if arg.splat_type?
+              splats << arg
+            elsif arg.sym_type?
+              symbols << arg
+            elsif arg.pair_type?
+              hash_items << arg
+            elsif arg.hash_type?
+              arg.children.each { |child| hash_items << child }
+            else
+              others << arg
+            end
+          end
+
+          sorted_symbols = symbols.sort_by { |symbol| symbol.value.to_s }
+          sorted_pairs = hash_items.select(&:pair_type?).sort_by { |pair| extract_hash_key(pair) }
+          sorted_hash_items = hash_items.map do |item|
+            item.pair_type? ? sorted_pairs.shift : item
+          end
+
+          splats + others + sorted_symbols + sorted_hash_items
+        end
+
+        def extract_hash_key(pair_node)
+          key = pair_node.key
+          key.sym_type? ? key.value.to_s : key.source
+        end
+
+        def args_match?(original, sorted)
+          original_flat = flatten_args(original)
+          original_flat.map(&:source) == sorted.map(&:source)
+        end
+
+        def flatten_args(args)
+          args.flat_map do |arg|
+            if arg.hash_type?
+              arg.children
+            else
+              arg
+            end
+          end
+        end
+
+        def arguments_range(node)
+          first_arg = node.arguments.first
+          last_arg = node.arguments.last
+          first_arg.source_range.join(last_arg.source_range)
+        end
+
+        def format_arguments(sorted_args, node)
+          return sorted_args.map(&:source).join(", ") if single_line_call?(node)
+
+          indent = argument_indent(node)
+          all_args = sorted_args.dup
+          first = all_args.shift
+
+          lines = [first.source]
+          all_args.each { |arg| lines << "#{indent}#{arg.source}" }
+
+          lines.join(",\n")
+        end
+
+        def single_line_call?(node)
+          node.source_range.first_line == node.source_range.last_line
+        end
+
+        def argument_indent(node)
+          first_arg = node.arguments.first
+          " " * first_arg.source_range.column
+        end
+      end
+    end
+  end
+end

lib/rubocop/cop/teamtailor_cops.rb

@@ -1,3 +1,4 @@
 # frozen_string_literal: true
 
+require_relative "teamtailor/alphabetical_serializer_attributes"
 require_relative "teamtailor/no_embeddings_in_active_model_serializer"