Enable Performance/MapCompact cop

Follow up to #42053.

.rubocop.yml

@@ -253,6 +253,9 @@ Performance/BindCall:
 Performance/FlatMap:
   Enabled: true
 
+Performance/MapCompact:
+  Enabled: true
+
 Performance/RedundantMerge:
   Enabled: true
 

Gemfile.lock

@@ -221,6 +221,9 @@ GEM
       tzinfo
     event_emitter (0.2.6)
     eventmachine (1.2.7)
+    eventmachine (1.2.7-java)
+    eventmachine (1.2.7-x64-mingw32)
+    eventmachine (1.2.7-x86-mingw32)
     execjs (2.7.0)
     faraday (1.3.0)
       faraday-net_http (~> 1.0)
@@ -288,12 +291,14 @@ GEM
     hiredis (0.6.3)
     hiredis (0.6.3-java)
     http_parser.rb (0.6.0)
+    http_parser.rb (0.6.0-java)
     httpclient (2.8.3)
     i18n (1.8.10)
       concurrent-ruby (~> 1.0)
     image_processing (1.12.1)
       mini_magick (>= 4.9.5, < 5)
       ruby-vips (>= 2.0.17, < 3)
+    jar-dependencies (0.4.1)
     jdbc-mysql (5.1.47)
     jdbc-postgres (42.2.14)
     jdbc-sqlite3 (3.28.0)
@@ -305,6 +310,7 @@ GEM
       mustache
       nokogiri
     libxml-ruby (3.2.1)
+    libxml-ruby (3.2.1-x64-mingw32)
     listen (3.5.1)
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
@@ -361,7 +367,11 @@ GEM
       ast (~> 2.4.1)
     path_expander (1.1.0)
     pg (1.2.3)
+    pg (1.2.3-x64-mingw32)
+    pg (1.2.3-x86-mingw32)
     psych (3.3.1)
+    psych (3.3.1-java)
+      jar-dependencies (>= 0.1.7)
     public_suffix (4.0.6)
     puma (5.2.2)
       nio4r (~> 2.0)
@@ -417,7 +427,7 @@ GEM
     retriable (3.1.2)
     rexml (3.2.5)
     rouge (3.26.0)
-    rubocop (1.12.1)
+    rubocop (1.13.0)
       parallel (~> 1.10)
       parser (>= 3.0.0.0)
       rainbow (>= 2.2.2, < 4.0)
@@ -430,8 +440,8 @@ GEM
       parser (>= 2.7.1.5)
     rubocop-packaging (0.5.1)
       rubocop (>= 0.89, < 2.0)
-    rubocop-performance (1.10.2)
-      rubocop (>= 0.90.0, < 2.0)
+    rubocop-performance (1.11.0)
+      rubocop (>= 1.7.0, < 2.0)
       rubocop-ast (>= 0.4.0)
     rubocop-rails (2.9.1)
       activesupport (>= 4.2.0)

actionpack/lib/action_dispatch/journey/gtg/transition_table.rb

@@ -130,7 +130,7 @@ def visualizer(paths, title = "FSM")
           states    = "function tt() { return #{to_json}; }"
 
           fun_routes = paths.sample(3).map do |ast|
-            ast.map { |n|
+            ast.filter_map { |n|
               case n
               when Nodes::Symbol
                 case n.left
@@ -143,7 +143,7 @@ def visualizer(paths, title = "FSM")
               else
                 nil
               end
-            }.compact.join
+            }.join
           end
 
           stylesheets = [fsm_css]

actiontext/lib/action_text/encryption.rb

@@ -31,7 +31,7 @@ def has_encrypted_rich_texts?
 
       def encryptable_rich_texts
         @encryptable_rich_texts ||= self.class.rich_text_association_names
-          .collect { |attribute_name| send(attribute_name) }.compact
+          .filter_map { |attribute_name| send(attribute_name) }
           .find_all { |record| record.is_a?(ActionText::EncryptedRichText) }
       end
   end

actionview/lib/action_view/helpers/form_options_helper.rb

@@ -793,9 +793,9 @@ def extract_selected_and_disabled(selected)
 
         def extract_values_from_collection(collection, value_method, selected)
           if selected.is_a?(Proc)
-            collection.map do |element|
+            collection.filter_map do |element|
               element.public_send(value_method) if selected.call(element)
-            end.compact
+            end
           else
             selected
           end

activemodel/lib/active_model/attribute_methods.rb

@@ -399,7 +399,7 @@ def attribute_method_matchers_cache
 
         def attribute_method_matchers_matching(method_name)
           attribute_method_matchers_cache.compute_if_absent(method_name) do
-            attribute_method_matchers.map { |matcher| matcher.match(method_name) }.compact
+            attribute_method_matchers.filter_map { |matcher| matcher.match(method_name) }
           end
         end
 

activemodel/lib/active_model/validations/confirmation.rb

@@ -19,13 +19,13 @@ def validate_each(record, attribute, value)
 
       private
         def setup!(klass)
-          klass.attr_reader(*attributes.map do |attribute|
+          klass.attr_reader(*attributes.filter_map do |attribute|
             :"#{attribute}_confirmation" unless klass.method_defined?(:"#{attribute}_confirmation")
-          end.compact)
+          end)
 
-          klass.attr_writer(*attributes.map do |attribute|
+          klass.attr_writer(*attributes.filter_map do |attribute|
             :"#{attribute}_confirmation" unless klass.method_defined?(:"#{attribute}_confirmation=")
-          end.compact)
+          end)
         end
 
         def confirmation_value_equal?(record, attribute, value, confirmed)

activerecord/lib/active_record/associations/preloader/branch.rb

@@ -46,9 +46,9 @@ def target_classes
 
         def likely_reflections
           parent_classes = parent.target_classes
-          parent_classes.map do |parent_klass|
+          parent_classes.filter_map do |parent_klass|
             parent_klass._reflect_on_association(@association)
-          end.compact
+          end
         end
 
         def root?

activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb

@@ -498,10 +498,10 @@ def build_fixture_sql(fixtures, table_name)
         end
 
         def build_fixture_statements(fixture_set)
-          fixture_set.map do |table_name, fixtures|
+          fixture_set.filter_map do |table_name, fixtures|
             next if fixtures.empty?
             build_fixture_sql(fixtures, table_name)
-          end.compact
+          end
         end
 
         def build_truncate_statement(table_name)

activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb

@@ -787,14 +787,13 @@ def configure_connection
           end
 
           # Gather up all of the SET variables...
-          variable_assignments = variables.map do |k, v|
+          variable_assignments = variables.filter_map do |k, v|
             if defaults.include?(v)
               "@@SESSION.#{k} = DEFAULT" # Sets the value to the global or compile default
             elsif !v.nil?
               "@@SESSION.#{k} = #{quote(v)}"
             end
-            # or else nil; compact to clear nils out
-          end.compact.join(", ")
+          end.join(", ")
 
           # ...and send them all in one query
           execute("SET #{encoding} #{sql_mode_assignment} #{variable_assignments}", "SCHEMA")

activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb

@@ -917,9 +917,7 @@ def add_pg_decoders
             WHERE t.typname IN (%s)
           SQL
           coders = execute_and_clear(query, "SCHEMA", []) do |result|
-            result
-              .map { |row| construct_coder(row, coders_by_name[row["typname"]]) }
-              .compact
+            result.filter_map { |row| construct_coder(row, coders_by_name[row["typname"]]) }
           end
 
           map = PG::TypeMapByOid.new

activerecord/lib/active_record/connection_adapters/sqlite3/schema_statements.rb

@@ -6,7 +6,7 @@ module SQLite3
       module SchemaStatements # :nodoc:
         # Returns an array of indexes for the given table.
         def indexes(table_name)
-          exec_query("PRAGMA index_list(#{quote_table_name(table_name)})", "SCHEMA").map do |row|
+          exec_query("PRAGMA index_list(#{quote_table_name(table_name)})", "SCHEMA").filter_map do |row|
             # Indexes SQLite creates implicitly for internal use start with "sqlite_".
             # See https://www.sqlite.org/fileformat2.html#intschema
             next if row["name"].start_with?("sqlite_")
@@ -49,7 +49,7 @@ def indexes(table_name)
               where: where,
               orders: orders
             )
-          end.compact
+          end
         end
 
         def add_foreign_key(from_table, to_table, **options)

activerecord/lib/active_record/core.rb

@@ -796,11 +796,11 @@ def inspect
       # We check defined?(@attributes) not to issue warnings if the object is
       # allocated but not initialized.
       inspection = if defined?(@attributes) && @attributes
-        self.class.attribute_names.collect do |name|
+        self.class.attribute_names.filter_map do |name|
           if _has_attribute?(name)
             "#{name}: #{attribute_for_inspect(name)}"
           end
-        end.compact.join(", ")
+        end.join(", ")
       else
         "not initialized"
       end

activerecord/lib/active_record/insert_all.rb

@@ -196,11 +196,11 @@ def updatable_columns
         end
 
         def touch_model_timestamps_unless(&block)
-          model.timestamp_attributes_for_update_in_model.map do |column_name|
+          model.timestamp_attributes_for_update_in_model.filter_map do |column_name|
             if touch_timestamp_attribute?(column_name)
               "#{column_name}=(CASE WHEN (#{updatable_columns.map(&block).join(" AND ")}) THEN #{model.quoted_table_name}.#{column_name} ELSE CURRENT_TIMESTAMP END),"
             end
-          end.compact.join
+          end.join
         end
 
         def raw_update_sql

activerecord/lib/active_record/migration.rb

@@ -1159,13 +1159,13 @@ def migrations # :nodoc:
     def migrations_status # :nodoc:
       db_list = schema_migration.normalized_versions
 
-      file_list = migration_files.map do |file|
+      file_list = migration_files.filter_map do |file|
         version, name, scope = parse_migration_filename(file)
         raise IllegalMigrationNameError.new(file) unless version
         version = schema_migration.normalize_migration_number(version)
         status = db_list.delete(version) ? "up" : "down"
         [status, version, (name + scope).humanize]
-      end.compact
+      end
 
       db_list.map! do |version|
         ["up", version, "********** NO FILE **********"]

activerecord/lib/active_record/tasks/mysql_database_tasks.rb

@@ -94,7 +94,7 @@ def prepare_command_options
             sslcapath: "--ssl-capath",
             sslcipher: "--ssl-cipher",
             sslkey:    "--ssl-key"
-          }.map { |opt, arg| "#{arg}=#{configuration_hash[opt]}" if configuration_hash[opt] }.compact
+          }.filter_map { |opt, arg| "#{arg}=#{configuration_hash[opt]}" if configuration_hash[opt] }
 
           args
         end

activerecord/lib/active_record/timestamp.rb

@@ -148,8 +148,7 @@ def current_time_from_proper_timezone
 
     def max_updated_column_timestamp
       timestamp_attributes_for_update_in_model
-        .map { |attr| self[attr]&.to_time }
-        .compact
+        .filter_map { |attr| self[attr]&.to_time }
         .max
     end
 

activesupport/lib/active_support/core_ext/object/to_query.rb

@@ -75,11 +75,11 @@ class Hash
   #
   # This method is also aliased as +to_param+.
   def to_query(namespace = nil)
-    query = collect do |key, value|
+    query = filter_map do |key, value|
       unless (value.is_a?(Hash) || value.is_a?(Array)) && value.empty?
         value.to_query(namespace ? "#{namespace}[#{key}]" : key)
       end
-    end.compact
+    end
 
     query.sort! unless namespace.to_s.include?("[]")
     query.join("&")

railties/lib/rails/generators/test_unit/scaffold/scaffold_generator.rb

@@ -45,13 +45,13 @@ def attributes_string
         def attributes_hash
           return {} if attributes_names.empty?
 
-          attributes_names.map do |name|
+          attributes_names.filter_map do |name|
             if %w(password password_confirmation).include?(name) && attributes.any?(&:password_digest?)
               ["#{name}", "'secret'"]
             elsif !virtual?(name)
               ["#{name}", "@#{singular_table_name}.#{name}"]
             end
-          end.compact.sort.to_h
+          end.sort.to_h
         end
 
         def boolean?(name)

railties/lib/rails/tasks/zeitwerk.rake

@@ -54,11 +54,11 @@ namespace :zeitwerk do
     end
 
     require "active_support/core_ext/object/try"
-    eager_load_paths = Rails.configuration.eager_load_namespaces.map do |eln|
+    eager_load_paths = Rails.configuration.eager_load_namespaces.filter_map do |eln|
       # Quick regression fix for 6.0.3 to support namespaces that do not have
       # eager load paths, like the recently added i18n. I'll rewrite this task.
       eln.try(:config).try(:eager_load_paths)
-    end.compact.flatten
+    end.flatten
 
     not_checked = ActiveSupport::Dependencies.autoload_paths - eager_load_paths
     not_checked.select! { |dir| Dir.exist?(dir) }