Deprecate Template#mime_type

2 files changed, 13 insertions, 0 deletions

diff --git a/actionpack/lib/action_view/template.rb b/actionpack/lib/action_view/template.rb
index c36b06a83d..379cdc8a25 100644
--- a/actionpack/lib/action_view/template.rb
+++ b/actionpack/lib/action_view/template.rb
@@ -1,5 +1,6 @@
 require 'active_support/core_ext/object/try'
 require 'active_support/core_ext/kernel/singleton_class'
+require 'active_support/deprecation'
 require 'thread'
 
 module ActionView
@@ -147,6 +148,11 @@ module ActionView
       handle_render_error(view, e)
     end
 
+    def mime_type
+      ActiveSupport::Deprecation.warn 'Template#mime_type is deprecated and will be removed in Rails 4.1. Please use type method instead.'
+      @mime_type ||= Mime::Type.lookup_by_extension(@formats.first.to_s) if @formats.first
+    end
+
     def type
       @type ||= Types[@formats.first] if @formats.first
     end
diff --git a/actionpack/test/template/template_test.rb b/actionpack/test/template/template_test.rb
index 061f5bb53f..86ba5f3b4d 100644
--- a/actionpack/test/template/template_test.rb
+++ b/actionpack/test/template/template_test.rb
@@ -59,6 +59,13 @@ class TestERBTemplate < ActiveSupport::TestCase
     @context = Context.new
   end
 
+  def test_mime_type_is_deprecated
+    template = new_template
+    assert_deprecated 'Template#mime_type is deprecated and will be removed' do
+      template.mime_type
+    end
+  end
+
   def test_basic_template
     @template = new_template
     assert_equal "Hello", render