Clean up extensions a bit. Removes newest form of registering extensions, more consistently sets and uses an extension's ext_name, and makes a lot of things errors instead of just log messages in hopes that people can't get too far with a messed-up config.

middleman-core/fixtures/feature-params-app/config.rb

@@ -11,6 +11,6 @@ class ExtensionA < ::Middleman::Extension
   option :hola, '', ''
 end
 
-ExtensionA.register
+Middleman::Extensions.register :extension_a, ExtensionA
 
 activate :extension_a, :hello => "world", :hola => "mundo"

middleman-core/fixtures/v4-extension-callbacks/config.rb

@@ -16,7 +16,7 @@ class ExtensionOne < ::Middleman::Extension
   end
 end
 
-ExtensionOne.register
+Middleman::Extensions.register :extension_one, ExtensionOne
 
 class ExtensionTwo < ::Middleman::Extension
   helpers do
@@ -36,7 +36,7 @@ class ExtensionTwo < ::Middleman::Extension
   end
 end
 
-ExtensionTwo.register
+Middleman::Extensions.register :extension_two, ExtensionTwo
 
 activate :extension_one
-activate :extension_two
+activate :extension_two

middleman-core/lib/middleman-core/application.rb

@@ -196,8 +196,10 @@ module Middleman
       activate :default_helpers
       activate :lorem
 
-      if defined?(Middleman::CoreExtensions::Compass)
+      begin
         activate :compass
+      rescue LoadError
+        # Compass is not available, don't complain about it
       end
 
       # Evaluate a passed block if given

middleman-core/lib/middleman-core/core_extensions.rb

@@ -27,68 +27,97 @@ require 'middleman-core/core_extensions/routing'
 require 'middleman-core/core_extensions/show_exceptions'
 
 # Setup default helpers
-require 'middleman-core/core_extensions/default_helpers'
-
-require 'middleman-core/core_extensions/i18n'
+Middleman::Extensions.register :default_helpers do
+  require 'middleman-core/core_extensions/default_helpers'
+  Middleman::CoreExtensions::DefaultHelpers
+end
 
 # Compass framework
-begin
+Middleman::Extensions.register :compass do
   require 'middleman-core/core_extensions/compass'
-rescue LoadError
+  Middleman::CoreExtensions::Compass
 end
 
 ###
 # Setup Optional Extensions
 ###
 
+Middleman::Extensions.register :i18n do
+  require 'middleman-core/core_extensions/i18n'
+  Middleman::CoreExtensions::Internationalization
+end
+
 # CacheBuster adds a query string to assets in dynamic templates to
 # avoid browser caches failing to update to your new content.
-require 'middleman-core/extensions/cache_buster'
-Middleman::Extensions::CacheBuster.register
+Middleman::Extensions.register :cache_buster do
+  require 'middleman-core/extensions/cache_buster'
+  Middleman::Extensions::CacheBuster
+end
 
 # RelativeAssets allow any asset path in dynamic templates to be either
 # relative to the root of the project or use an absolute URL.
-require 'middleman-core/extensions/relative_assets'
-Middleman::Extensions::RelativeAssets.register
+Middleman::Extensions.register :relative_assets do
+  require 'middleman-core/extensions/relative_assets'
+  Middleman::Extensions::RelativeAssets
+end
 
 # AssetHost allows you to setup multiple domains to host your static
 # assets. Calls to asset paths in dynamic templates will then rotate
 # through each of the asset servers to better spread the load.
-require 'middleman-core/extensions/asset_host'
-Middleman::Extensions::AssetHost.register
+Middleman::Extensions.register :asset_host do
+  require 'middleman-core/extensions/asset_host'
+  Middleman::Extensions::AssetHost
+end
 
 # MinifyCss compresses CSS
-require 'middleman-core/extensions/minify_css'
-Middleman::Extensions::MinifyCss.register
+Middleman::Extensions.register :minify_css do
+  require 'middleman-core/extensions/minify_css'
+  Middleman::Extensions::MinifyCss
+end
 
 # MinifyJavascript compresses JS
-require 'middleman-core/extensions/minify_javascript'
-Middleman::Extensions::MinifyJavascript.register
+Middleman::Extensions.register :minify_javascript do
+  require 'middleman-core/extensions/minify_javascript'
+  Middleman::Extensions::MinifyJavascript
+end
 
 # GZIP assets and pages during build
-require 'middleman-core/extensions/gzip'
-Middleman::Extensions::Gzip.register
+Middleman::Extensions.register :gzip do
+  require 'middleman-core/extensions/gzip'
+  Middleman::Extensions::Gzip
+end
 
 # AssetHash appends a hash of the file contents to the assets filename
 # to avoid browser caches failing to update to your new content.
-require 'middleman-core/extensions/asset_hash'
-Middleman::Extensions::AssetHash.register
+Middleman::Extensions.register :asset_hash do
+  require 'middleman-core/extensions/asset_hash'
+  Middleman::Extensions::AssetHash
+end
 
 # Provide Apache-style index.html files for directories
-require 'middleman-core/extensions/directory_indexes'
-Middleman::Extensions::DirectoryIndexes.register
+Middleman::Extensions.register :directory_indexes do
+  require 'middleman-core/extensions/directory_indexes'
+  Middleman::Extensions::DirectoryIndexes
+end
 
 # Lorem provides a handful of helpful prototyping methods to generate
 # words, paragraphs, fake images, names and email addresses.
-require 'middleman-core/extensions/lorem'
+Middleman::Extensions.register :lorem do
+  require 'middleman-core/extensions/lorem'
+  Middleman::Extensions::Lorem
+end
 
 # AutomaticImageSizes inspects the images used in your dynamic templates
 # and automatically adds width and height attributes to their HTML
 # elements.
-require 'middleman-core/extensions/automatic_image_sizes'
-Middleman::Extensions::AutomaticImageSizes.register
+Middleman::Extensions.register :automatic_image_sizes do
+  require 'middleman-core/extensions/automatic_image_sizes'
+  Middleman::Extensions::AutomaticImageSizes
+end
 
 # AutomaticAltTags uses the file name of the `image_tag` to generate
 # a default `:alt` value.
-require 'middleman-core/extensions/automatic_alt_tags'
-Middleman::Extensions::AutomaticAltTags.register
+Middleman::Extensions.register :automatic_alt_tags do
+  require 'middleman-core/extensions/automatic_alt_tags'
+  Middleman::Extensions::AutomaticAltTags
+end

middleman-core/lib/middleman-core/core_extensions/compass.rb

@@ -73,5 +73,3 @@ class Middleman::CoreExtensions::Compass < ::Middleman::Extension
     end
   end
 end
-
-Middleman::CoreExtensions::Compass.register

middleman-core/lib/middleman-core/core_extensions/default_helpers.rb

@@ -259,5 +259,3 @@ class Middleman::CoreExtensions::DefaultHelpers < ::Middleman::Extension
     end
   end
 end
-
-Middleman::CoreExtensions::DefaultHelpers.register

middleman-core/lib/middleman-core/core_extensions/extensions.rb

@@ -88,26 +88,19 @@ module Middleman
         # @param [Symbol, Module] ext Which extension to activate
         # @return [void]
         def activate(ext, options={}, &block)
-          if extension = ::Middleman::Extensions.load(ext)
-            if extension.ancestors.include?(::Middleman::Extension)
-              logger.debug "== Activating: #{ext}"
+          extension = ::Middleman::Extensions.load(ext)
+          logger.debug "== Activating: #{ext}"
 
-              if extension.supports_multiple_instances?
-                extensions[ext] ||= {}
-                key = "instance_#{extensions[ext].keys.length}"
-                extensions[ext][key] = extension.new(self.class, options, &block)
-              else
-                if extensions[ext]
-                  logger.error "== #{ext} already activated."
-                else
-                  extensions[ext] = extension.new(self.class, options, &block)
-                end
-              end
-            else
-              logger.error "!! Tried to activate old-style extension: #{ext}"
-            end
+          if extension.supports_multiple_instances?
+            extensions[ext] ||= {}
+            key = "instance_#{extensions[ext].keys.length}"
+            extensions[ext][key] = extension.new(self.class, options, &block)
           else
-            logger.error "!! Unknown Extension: #{ext}"
+            if extensions[ext]
+              raise "#{ext} has already been activated and cannot be re-activated."
+            else
+              extensions[ext] = extension.new(self.class, options, &block)
+            end
           end
         end
 

middleman-core/lib/middleman-core/core_extensions/i18n.rb

@@ -201,5 +201,3 @@ class Middleman::CoreExtensions::Internationalization < ::Middleman::Extension
     end
   end
 end
-
-Middleman::CoreExtensions::Internationalization.register(:i18n)

middleman-core/lib/middleman-core/extension.rb

@@ -33,14 +33,6 @@ module Middleman
         self.defined_helpers += m
       end
 
-      def extension_name
-        self.ext_name || self.name.underscore.split('/').last.to_sym
-      end
-
-      def register(n=self.extension_name)
-        ::Middleman::Extensions.register(n, self)
-      end
-
       def activate
         new(::Middleman::Application)
       end
@@ -56,7 +48,7 @@ module Middleman
       end
 
       def activated_extension(instance)
-        name = instance.class.extension_name
+        name = instance.class.ext_name
         return unless @_extension_activation_callbacks && @_extension_activation_callbacks[name]
         @_extension_activation_callbacks[name].each do |block|
           block.arity == 1 ? block.call(instance) : block.call()
@@ -136,7 +128,7 @@ module Middleman
         end
 
         if ext.respond_to?(:manipulate_resource_list)
-          ext.app.sitemap.register_resource_list_manipulator(ext.class.extension_name, ext)
+          ext.app.sitemap.register_resource_list_manipulator(ext.class.ext_name, ext)
         end
       end
     end

middleman-core/lib/middleman-core/extensions.rb

@@ -13,7 +13,16 @@ module Middleman
       #     activate :my_extension
       #
       # Provide your extension module either as the namespace
-      # parameter, or return it from the block:
+      # parameter:
+      #
+      #     Middleman::Extensions.register(:my_extension, MyExtension)
+      #
+      # Or return it from a block:
+      #
+      #     Middleman::Extensions.register(:my_extension) do
+      #       require 'my_extension'
+      #       MyExtension
+      #     end
       #
       # @param [Symbol] name The name of the extension
       # @param [Module] namespace The extension module
@@ -22,34 +31,49 @@ module Middleman
       #        you the ability to require other files only when the
       #        extension is activated.
       def register(name, namespace=nil, &block)
-        # If we've already got a matching extension that passed the
-        # version check, bail out.
-        return if registered.has_key?(name.to_sym) && !registered[name.to_sym].is_a?(String)
+        # If we've already got an extension registered under this name, bail out
+        if registered.has_key?(name.to_sym)
+          raise "There is already an extension registered with the name '#{name}'"
+        end
 
         registered[name.to_sym] = if block_given?
           block
-        elsif namespace
+        elsif namespace && namespace.ancestors.include?(::Middleman::Extension)
           namespace
+        else
+          raise "You must provide a Middleman::Extension or a block that returns a Middleman::Extension"
         end
       end
 
       # Load an extension by name, evaluating block definition if necessary.
       def load(name)
         name = name.to_sym
-        return nil unless registered.has_key?(name)
+
+        unless registered.has_key?(name)
+          raise "Unknown Extension: #{name}. Check the name and make sure you have referenced the extension's gem in your Gemfile."
+        end
 
         extension = registered[name]
         if extension.is_a?(Proc)
-          extension = extension.call() || nil
+          extension = extension.call()
           registered[name] = extension
         end
 
+        if !extension.ancestors.include?(::Middleman::Extension)
+          raise "Tried to activate old-style extension: #{name}. They are no longer supported."
+        end
+
+        # Set the extension's name to whatever it was registered as.
+        extension.ext_name = name
+
         extension
       end
     end
   end
 
-  # Where to look in gems for extensions to auto-register
+  # Where to look in gems for extensions to auto-register. Since most extensions are
+  # called out in a Gemfile, this is really only useful for template extensions that get
+  # used by "middleman init".
   EXTENSION_FILE = File.join('lib', 'middleman_extension.rb') unless const_defined?(:EXTENSION_FILE)
 
   class << self

middleman-core/lib/middleman-core/extensions/lorem.rb

@@ -174,5 +174,3 @@ class Middleman::Extensions::Lorem < ::Middleman::Extension
     end
   end
 end
-
-Middleman::Extensions::Lorem.register