Deprecate register_engine

lib/sprockets.rb

@@ -123,25 +123,33 @@ module Sprockets
 
   # Mmm, CoffeeScript
   require 'sprockets/coffee_script_processor'
-  register_engine '.coffee', CoffeeScriptProcessor, mime_type: 'application/javascript'
+  Deprecation.silence do
+    register_engine '.coffee', CoffeeScriptProcessor, mime_type: 'application/javascript'
+  end
 
   # JST engines
   require 'sprockets/eco_processor'
   require 'sprockets/ejs_processor'
   require 'sprockets/jst_processor'
-  register_engine '.jst', JstProcessor, mime_type: 'application/javascript'
-  register_engine '.eco', EcoProcessor, mime_type: 'application/javascript'
-  register_engine '.ejs', EjsProcessor, mime_type: 'application/javascript'
+  Deprecation.silence do
+    register_engine '.jst', JstProcessor, mime_type: 'application/javascript'
+    register_engine '.eco', EcoProcessor, mime_type: 'application/javascript'
+    register_engine '.ejs', EjsProcessor, mime_type: 'application/javascript'
+  end
 
   # CSS engines
   require 'sprockets/sass_processor'
-  register_engine '.sass', SassProcessor, mime_type: 'text/css'
-  register_engine '.scss', ScssProcessor, mime_type: 'text/css'
+  Deprecation.silence do
+    register_engine '.sass', SassProcessor, mime_type: 'text/css'
+    register_engine '.scss', ScssProcessor, mime_type: 'text/css'
+  end
   register_bundle_metadata_reducer 'text/css', :sass_dependencies, Set.new, :+
 
   # Other
   require 'sprockets/erb_processor'
-  register_engine '.erb', ERBProcessor, mime_type: 'text/plain'
+  Deprecation.silence do
+    register_engine '.erb', ERBProcessor, mime_type: 'text/plain'
+  end
 
   register_dependency_resolver 'environment-version' do |env|
     env.version

lib/sprockets/engines.rb

@@ -51,6 +51,8 @@ def engine_mime_types
     #     environment.register_engine '.coffee', CoffeeScriptProcessor
     #
     def register_engine(ext, klass, options = {})
+      Deprecation.new([caller.first]).warn("`register_engine` is deprecated please register a mime type and use `register_compressor` or `register_transformer`")
+
       ext = Sprockets::Utils.normalize_extension(ext)
 
       self.computed_config = {}

test/test_context.rb

@@ -90,6 +90,12 @@ def initialize(file, &block)
       @data = block.call
     end
 
+    def self.call(input)
+      context = input[:environment].context_class.new(input)
+      result  = self.new(nil, &Proc.new { input[:data]} ).render(context)
+      { data: result }
+    end
+
     def render(context, locals = {})
       data = @data
       data.gsub(/url\(\"(.+?)\"\)/) do
@@ -102,7 +108,8 @@ def render(context, locals = {})
   end
 
   test "custom processor using Context#resolve and Context#depend_on" do
-    @env.register_engine '.embed', DataUriProcessor
+    @env.register_mime_type 'text/css+embed', extensions: ['.css.embed']
+    @env.register_transformer 'text/css+embed', 'text/css', DataUriProcessor
 
     assert_equal ".pow {\n  background: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZoAAAEsCAMAAADNS4U5AAAAGXRFWHRTb2Z0\n",
       @env["sprite.css"].to_s.lines.to_a[0..1].join

test/test_engines.rb

@@ -28,7 +28,11 @@ def render(context, locals = {})
 class TestEngines < Sprockets::TestCase
   test "registering engine" do
     env = new_environment
-    env.register_engine ".alert", AlertProcessor
+
+    Sprockets::SilenceDeprecation.silence do
+      env.register_engine ".alert", AlertProcessor
+    end
+
     asset = env["hello.alert"]
     assert_equal "alert(\"Hello world!\\n\");\n", asset.to_s
     assert_equal 'application/javascript', asset.content_type