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.

7 files changed, 31 insertions, 19 deletions

diff --git a/actionview/lib/action_view/file_template.rb b/actionview/lib/action_view/file_template.rb
index 4921074383..43206f02e5 100644
--- a/actionview/lib/action_view/file_template.rb
+++ b/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
diff --git a/actionview/lib/action_view/helpers/cache_helper.rb b/actionview/lib/action_view/helpers/cache_helper.rb
index 6b69b71947..020aebeea3 100644
--- a/actionview/lib/action_view/helpers/cache_helper.rb
+++ b/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}"
diff --git a/actionview/lib/action_view/renderer/abstract_renderer.rb b/actionview/lib/action_view/renderer/abstract_renderer.rb
index f1b4c9b92d..475452f1bb 100644
--- a/actionview/lib/action_view/renderer/abstract_renderer.rb
+++ b/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
diff --git a/actionview/lib/action_view/renderer/template_renderer.rb b/actionview/lib/action_view/renderer/template_renderer.rb
index 87f6cf3de3..83b990b081 100644
--- a/actionview/lib/action_view/renderer/template_renderer.rb
+++ b/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
diff --git a/actionview/lib/action_view/template.rb b/actionview/lib/action_view/template.rb
index 8ba03027d3..cc5e0cbb4f 100644
--- a/actionview/lib/action_view/template.rb
+++ b/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
 
diff --git a/actionview/lib/action_view/template/html.rb b/actionview/lib/action_view/template/html.rb
index a262c6d9ad..ecd1c31e79 100644
--- a/actionview/lib/action_view/template/html.rb
+++ b/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
diff --git a/actionview/lib/action_view/template/text.rb b/actionview/lib/action_view/template/text.rb
index f8d6c2811f..c5fd55f1b3 100644
--- a/actionview/lib/action_view/template/text.rb
+++ b/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