safely allow loading jekyll customizations from inside a site

bin/jekyll

@@ -62,6 +62,14 @@ opts = OptionParser.new do |opts|
     end
   end
 
+  opts.on("--extensions", "Load Jekyll extensions from _lib directory") do
+    options['extensions'] = true
+  end
+  
+  opts.on("--no-extensions", "Do not load Jekyll extensions") do
+    options['extensions'] = false
+  end
+
   opts.on("--version", "Display current version") do
     puts "Jekyll " + Jekyll.version
     exit 0

features/site_configuration.feature

@@ -61,3 +61,21 @@ Feature: Site configuration
     When I run jekyll
     Then the _site directory should exist
     And I should see "puts 'Hello world!'" in "_site/index.html"
+
+  Scenario: Load an extension from _lib
+    Given I have an "index.html" page that contains "{{ 'extension' | hello }}"
+    And I have a _lib directory
+    And I have a "_lib/hello.rb" file that contains "module Jekyll::Filters ; def hello(input) ; "hello #{input}" ; end ; end"
+    And I have a configuration file with "extensions" set to "true"
+    When I run jekyll
+    Then the _site directory should exist
+    And I should see "hello extension" in "_site/index.html"
+
+  Scenario: Skip loading extensions from _lib
+    Given I have an "index.html" page that contains "{{ 'extension' | hello }}"
+    And I have a _lib directory
+    And I have a "_lib/hello.rb" file that contains "module Jekyll::Filters ; def hello(input) ; "hello #{input}" ; end ; end"
+    And I have a configuration file with "extensions" set to "false"
+    When I run jekyll
+    Then the _site directory should exist
+    And I should not see "hello extension" in "_site/index.html"

features/step_definitions/jekyll_steps.rb

@@ -25,7 +25,7 @@ EOF
   end
 end
 
-Given /^I have an "(.*)" file that contains "(.*)"$/ do |file, text|
+Given /^I have an? "(.*)" file that contains "(.*)"$/ do |file, text|
   File.open(file, 'w') do |f|
     f.write(text)
     f.close
@@ -123,6 +123,10 @@ Then /^I should see "(.*)" in "(.*)"$/ do |text, file|
   assert_match Regexp.new(text), File.open(file).readlines.join
 end
 
+Then /^I should not see "(.*)" in "(.*)"$/ do |text, file|
+  assert_no_match Regexp.new(text), File.open(file).readlines.join
+end
+
 Then /^the "(.*)" file should not exist$/ do |file|
   assert !File.exists?(file)
 end

lib/jekyll.rb

@@ -42,6 +42,7 @@ module Jekyll
     'pygments'     => false,
     'markdown'     => 'maruku',
     'permalink'    => 'date',
+    'extensions'   => false,
 
     'maruku'       => {
       'use_tex'    => false,

lib/jekyll/site.rb

@@ -2,7 +2,8 @@ module Jekyll
 
   class Site
     attr_accessor :config, :layouts, :posts, :categories, :exclude,
-                  :source, :dest, :lsi, :pygments, :permalink_style, :tags
+                  :source, :dest, :lsi, :pygments, :permalink_style, :tags,
+                  :extensions
 
     # Initialize the site
     #   +config+ is a Hash containing site configurations details
@@ -17,6 +18,7 @@ module Jekyll
       self.pygments        = config['pygments']
       self.permalink_style = config['permalink'].to_sym
       self.exclude         = config['exclude'] || []
+      self.extensions      = config['extensions']
 
       self.reset
       self.setup
@@ -80,6 +82,12 @@ module Jekyll
         else
           raise "Invalid Markdown processor: '#{self.config['markdown']}' -- did you mean 'maruku' or 'rdiscount'?"
       end
+
+      # Load extensions from _lib folder
+      if self.extensions
+        # load instead of require so that jekyll --auto reloads changes
+        Dir["#{source}/_lib/*.rb"].each {|f| load f}
+      end
     end
 
     def textile(content)