Bugfixes and Rails Edge

Update to Rails 2.3.1.
  (Actually, not quite. Doesn't look like 2.3.1 will be released
   today, but I REALLY want to push these bugfixes out.)
Removed bundled Rack (Rails 2.3.1 comes bundled with Rack 1.0).
Add
     config.action_view.cache_template_loading = true
  to production environment.
Fix FastCGI bug (http://rubyforge.org/tracker/index.php?func=detail&aid=24191&group_id=186&atid=783).
Fix WikiWords bug (http://rubyforge.org/pipermail/instiki-users/2009-February/001181.html).

vendor/rails/actionpack/lib/action_controller/streaming.rb

@@ -1,5 +1,6 @@
 module ActionController #:nodoc:
-  # Methods for sending files and streams to the browser instead of rendering.
+  # Methods for sending arbitrary data and for streaming files to the browser,
+  # instead of rendering.
   module Streaming
     DEFAULT_SEND_FILE_OPTIONS = {
       :type         => 'application/octet-stream'.freeze,
@@ -103,8 +104,11 @@ module ActionController #:nodoc:
         end
       end
 
-      # Send binary data to the user as a file download.  May set content type, apparent file name,
-      # and specify whether to show data inline or download as an attachment.
+      # Sends the given binary data to the browser. This method is similar to
+      # <tt>render :text => data</tt>, but also allows you to specify whether
+      # the browser should display the response as a file attachment (i.e. in a
+      # download dialog) or as inline data. You may also set the content type,
+      # the apparent file name, and other things.
       #
       # Options:
       # * <tt>:filename</tt> - suggests a filename for the browser to use.
@@ -127,6 +131,10 @@ module ActionController #:nodoc:
       #   send_data image.data, :type => image.content_type, :disposition => 'inline'
       #
       # See +send_file+ for more information on HTTP Content-* headers and caching.
+      #
+      # <b>Tip:</b> if you want to stream large amounts of on-the-fly generated
+      # data to the browser, then use <tt>render :text => proc { ... }</tt>
+      # instead. See ActionController::Base#render for more information.
       def send_data(data, options = {}) #:doc:
         logger.info "Sending data #{options[:filename]}" if logger
         send_file_headers! options.merge(:length => data.size)
@@ -152,7 +160,7 @@ module ActionController #:nodoc:
         end
         content_type = content_type.to_s.strip # fixes a problem with extra '\r' with some browsers
 
-        headers.update(
+        headers.merge!(
           'Content-Length'            => options[:length],
           'Content-Type'              => content_type,
           'Content-Disposition'       => disposition,