Templates have one format

Templates only have one format.  Before this commit, templates would be
constructed with a single element array that contained the format.  This
commit eliminates the single element array and just implements a
`format` method.  This saves one array allocation per template.

actionmailer/lib/action_mailer/base.rb

@@ -973,7 +973,7 @@ module ActionMailer
         templates_name = headers[:template_name] || action_name
 
         each_template(Array(templates_path), templates_name).map do |template|
-          self.formats = template.formats
+          self.formats = [template.format]
           {
             body: render(template: template),
             content_type: template.type.to_s
@@ -986,7 +986,7 @@ module ActionMailer
         if templates.empty?
           raise ActionView::MissingTemplate.new(paths, name, paths, false, "mailer")
         else
-          templates.uniq(&:formats).each(&block)
+          templates.uniq(&:format).each(&block)
         end
       end
 

actionview/lib/action_view/file_template.rb

@@ -22,11 +22,11 @@ module ActionView
     # to ensure that references to the template object can be marshalled as well. This means forgoing
     # the marshalling of the compiler mutex and instantiating that again on unmarshalling.
     def marshal_dump # :nodoc:
-      [ @identifier, @handler, @compiled, @original_encoding, @locals, @virtual_path, @updated_at, @formats, @variants ]
+      [ @identifier, @handler, @compiled, @original_encoding, @locals, @virtual_path, @updated_at, @format, @variants ]
     end
 
     def marshal_load(array) # :nodoc:
-      @identifier, @handler, @compiled, @original_encoding, @locals, @virtual_path, @updated_at, @formats, @variants = *array
+      @identifier, @handler, @compiled, @original_encoding, @locals, @virtual_path, @updated_at, @format, @variants = *array
       @compile_mutex = Mutex.new
     end
   end

actionview/lib/action_view/helpers/cache_helper.rb

@@ -217,7 +217,7 @@ module ActionView
       end
 
       def digest_path_from_template(template) # :nodoc:
-        digest = Digestor.digest(name: template.virtual_path, format: template.formats.first, finder: lookup_context, dependencies: view_cache_dependencies)
+        digest = Digestor.digest(name: template.virtual_path, format: template.format, finder: lookup_context, dependencies: view_cache_dependencies)
 
         if digest.present?
           "#{template.virtual_path}:#{digest}"

actionview/lib/action_view/renderer/abstract_renderer.rb

@@ -68,7 +68,7 @@ module ActionView
       end
 
       def format
-        template.formats.first
+        template.format
       end
 
       EMPTY_SPACER = Struct.new(:body).new

actionview/lib/action_view/renderer/template_renderer.rb

@@ -8,7 +8,7 @@ module ActionView
       @details = extract_details(options)
       template = determine_template(options)
 
-      prepend_formats(template.formats)
+      prepend_formats(template.format)
 
       render_template(context, template, options[:layout], options[:locals] || {})
     end

actionview/lib/action_view/template.rb

@@ -125,8 +125,7 @@ module ActionView
     attr_accessor :locals, :variants, :virtual_path
 
     attr_reader :source, :identifier, :handler, :original_encoding, :updated_at
-
-    attr_reader :variable, :formats
+    attr_reader :variable, :format
 
     def initialize(source, identifier, handler, format: nil, **details)
       unless format
@@ -149,7 +148,7 @@ module ActionView
       end
 
       @updated_at        = details[:updated_at] || Time.now
-      @formats           = Array(format)
+      @format            = format
       @variants          = [details[:variant]]
       @compile_mutex     = Mutex.new
     end
@@ -158,6 +157,8 @@ module ActionView
     end
     deprecate :formats=
 
+    deprecate def formats; Array(format); end
+
     # Returns whether the underlying handler supports streaming. If so,
     # a streaming buffer *may* be passed when it starts rendering.
     def supports_streaming?
@@ -180,7 +181,7 @@ module ActionView
     end
 
     def type
-      @type ||= Types[@formats.first] if @formats.first
+      @type ||= Types[format]
     end
 
     # Receives a view object and return a template similar to self by using @virtual_path.
@@ -257,11 +258,11 @@ module ActionView
     # to ensure that references to the template object can be marshalled as well. This means forgoing
     # the marshalling of the compiler mutex and instantiating that again on unmarshalling.
     def marshal_dump # :nodoc:
-      [ @source, @identifier, @handler, @compiled, @original_encoding, @locals, @virtual_path, @updated_at, @formats, @variants ]
+      [ @source, @identifier, @handler, @compiled, @original_encoding, @locals, @virtual_path, @updated_at, @format, @variants ]
     end
 
     def marshal_load(array) # :nodoc:
-      @source, @identifier, @handler, @compiled, @original_encoding, @locals, @virtual_path, @updated_at, @formats, @variants = *array
+      @source, @identifier, @handler, @compiled, @original_encoding, @locals, @virtual_path, @updated_at, @format, @variants = *array
       @compile_mutex = Mutex.new
     end
 

actionview/lib/action_view/template/html.rb

@@ -1,15 +1,21 @@
 # frozen_string_literal: true
 
+require "active_support/deprecation"
+
 module ActionView #:nodoc:
   # = Action View HTML Template
   class Template #:nodoc:
     class HTML #:nodoc:
-      attr_accessor :type
+      attr_reader :type
 
       def initialize(string, type = nil)
+        unless type
+          ActiveSupport::Deprecation.warn "ActionView::Template::HTML#initialize requires a type parameter"
+          type = :html
+        end
+
         @string = string.to_s
-        @type   = Types[type] || type if type
-        @type ||= Types[:html]
+        @type   = type
       end
 
       def identifier
@@ -26,9 +32,12 @@ module ActionView #:nodoc:
         to_str
       end
 
-      def formats
-        [@type.respond_to?(:ref) ? @type.ref : @type.to_s]
+      def format
+        @type
       end
+
+      def formats; Array(format); end
+      deprecate :formats
     end
   end
 end

actionview/lib/action_view/template/text.rb

@@ -8,7 +8,6 @@ module ActionView #:nodoc:
 
       def initialize(string)
         @string = string.to_s
-        @type = Types[:text]
       end
 
       def identifier
@@ -25,9 +24,12 @@ module ActionView #:nodoc:
         to_str
       end
 
-      def formats
-        [@type.ref]
+      def format
+        :text
       end
+
+      def formats; Array(format); end
+      deprecate :formats
     end
   end
 end

actionview/test/actionpack/controller/view_paths_test.rb

@@ -144,7 +144,7 @@ class ViewLoadPathsTest < ActionController::TestCase
             template.identifier,
             template.handler,
               virtual_path: template.virtual_path,
-              format: template.formats
+              format: template.format
           )
         end
       end

actionview/test/template/digestor_test.rb

@@ -361,7 +361,7 @@ class TemplateDigestorTest < ActionView::TestCase
 
     def tree_template_formats(template_name)
       tree = ActionView::Digestor.tree(template_name, finder)
-      tree.flatten.map(&:template).compact.flat_map(&:formats)
+      tree.flatten.map(&:template).compact.map(&:format)
     end
 
     def disable_resolver_caching

actionview/test/template/html_test.rb

@@ -4,16 +4,16 @@ require "abstract_unit"
 
 class HTMLTest < ActiveSupport::TestCase
   test "formats returns symbol for recognized MIME type" do
-    assert_equal [:html], ActionView::Template::HTML.new("", :html).formats
+    assert_equal :html, ActionView::Template::HTML.new("", :html).format
   end
 
   test "formats returns string for recognized MIME type when MIME does not have symbol" do
     foo = Mime::Type.lookup("foo")
     assert_nil foo.to_sym
-    assert_equal ["foo"], ActionView::Template::HTML.new("", foo).formats
+    assert_equal "foo", ActionView::Template::HTML.new("", foo).format
   end
 
   test "formats returns string for unknown MIME type" do
-    assert_equal ["foo"], ActionView::Template::HTML.new("", "foo").formats
+    assert_equal "foo", ActionView::Template::HTML.new("", "foo").format
   end
 end

actionview/test/template/lookup_context_test.rb

@@ -125,7 +125,7 @@ class LookupContextTest < ActiveSupport::TestCase
     assert_called(ActionView::Template::Handlers::Builder, :default_format, returns: nil) do
       @lookup_context.formats = [:text]
       template = @lookup_context.find("hello", %w(test))
-      assert_equal [:text], template.formats
+      assert_equal :text, template.format
     end
   end
 

actionview/test/template/resolver_patterns_test.rb

@@ -19,7 +19,7 @@ class ResolverPatternsTest < ActiveSupport::TestCase
     assert_equal 1, templates.size, "expected one template"
     assert_equal "Hello custom patterns!", templates.first.source
     assert_equal "custom_pattern/path",    templates.first.virtual_path
-    assert_equal [:html],                  templates.first.formats
+    assert_equal :html,                    templates.first.format
   end
 
   def test_should_return_all_templates_when_ambiguous_pattern

actionview/test/template/testing/fixture_resolver_test.rb

@@ -15,6 +15,6 @@ class FixtureResolverTest < ActiveSupport::TestCase
     assert_equal 1, templates.size, "expected one template"
     assert_equal "this text",      templates.first.source
     assert_equal "arbitrary/path", templates.first.virtual_path
-    assert_equal [:html],          templates.first.formats
+    assert_equal :html,            templates.first.format
   end
 end

actionview/test/template/testing/null_resolver_test.rb

@@ -9,6 +9,6 @@ class NullResolverTest < ActiveSupport::TestCase
     assert_equal 1, templates.size, "expected one template"
     assert_equal "Template generated by Null Resolver", templates.first.source
     assert_equal "arbitrary/path.erb", templates.first.virtual_path.to_s
-    assert_equal [:html],          templates.first.formats
+    assert_equal :html, templates.first.format
   end
 end

actionview/test/template/text_test.rb

@@ -4,7 +4,7 @@ require "abstract_unit"
 
 class TextTest < ActiveSupport::TestCase
   test "formats always return :text" do
-    assert_equal [:text], ActionView::Template::Text.new("").formats
+    assert_equal :text, ActionView::Template::Text.new("").format
   end
 
   test "identifier should return 'text template'" do