Ensure that Sass::Plugin.update_stylesheets is run at least once per process, unless specifically forbidden.

lib/sass/plugin.rb

@@ -14,6 +14,12 @@ module Sass
         :full_exception     => true
       }
 
+      # Whether or not Sass has *ever* checked if the stylesheets need updates
+      # (in this Ruby instance).
+      def checked_for_updates
+        @@checked_for_updates
+      end
+
       # Gets various options for Sass. See README for details.
       #--
       # TODO: *DOCUMENT OPTIONS*
@@ -35,6 +41,7 @@ module Sass
       def update_stylesheets
         return if options[:never_update]
 
+        @@checked_for_updates = true
         Dir.glob(File.join(options[:template_location], "**", "*.sass")).entries.each do |file|
 
           # Get the relative path to the file with no extension

lib/sass/plugin/merb.rb

@@ -20,7 +20,11 @@ unless defined?(Sass::MERB_LOADED)
   
   class MerbHandler # :nodoc:
     def process_with_sass(request, response)
-      Sass::Plugin.update_stylesheets if Sass::Plugin.options[:always_update] || Sass::Plugin.options[:always_check]
+      if !Sass::Plugin.checked_for_updates ||
+          Sass::Plugin.options[:always_update] || Sass::Plugin.options[:always_check]
+        Sass::Plugin.update_stylesheets
+      end
+
       process_without_sass(request, response)
     end
     alias_method :process_without_sass, :process

lib/sass/plugin/rails.rb

@@ -11,7 +11,11 @@ unless defined?(Sass::RAILS_LOADED)
     class Base
       alias_method :sass_old_process, :process
       def process(*args)
-        Sass::Plugin.update_stylesheets if Sass::Plugin.options[:always_update] || Sass::Plugin.options[:always_check]
+        if !Sass::Plugin.checked_for_updates ||
+            Sass::Plugin.options[:always_update] || Sass::Plugin.options[:always_check]
+          Sass::Plugin.update_stylesheets
+        end
+
         sass_old_process(*args)
       end
     end