[Haml] Rails 2.3.6 compat: hack around the use of #safe_concat in #capture.

Closes gh-178

lib/haml/helpers/action_view_mods.rb

@@ -97,6 +97,22 @@ module ActionView
       end
     end
 
+    # For some reason, Rails 2.3.6 uses #safe_concat in #capture
+    # even when XSS support is disabled.
+    if Haml::Util.ap_2_3_6?
+      module TextHelper
+        def concat_with_haml(string, binding = nil)
+          if is_haml?
+            haml_buffer.buffer.concat(string)
+          else
+            concat_without_haml(string, binding)
+          end
+        end
+        alias_method :concat_without_haml, :concat
+        alias_method :concat, :concat_with_haml
+      end
+    end
+
     module TagHelper
       def content_tag_with_haml(name, *args, &block)
         return content_tag_without_haml(name, *args, &block) unless is_haml?

lib/haml/template.rb

@@ -64,14 +64,10 @@ else
   Haml::Template.try_enabling_xss_integration
 end
 
-require 'action_pack'
 # Rails 2.3.6 monkeypatches ERB in incompatible ways.
 # We fix our own subclass of ERB here so the Haml ERB filter
 # will continue to work.
-if defined?(ActionPack::VERSION::MAJOR) &&
-    ActionPack::VERSION::MAJOR == 2 &&
-    ActionPack::VERSION::MINOR == 3 &&
-    ActionPack::VERSION::TINY >= 6
+if Haml::Util.ap_2_3_6?
   class Haml::Filters::ERB::RealERB
     def set_eoutvar(compiler, eoutvar = '_erbout')
       compiler.put_cmd = "#{eoutvar}.concat"

lib/haml/util.rb

@@ -324,6 +324,18 @@ module Haml
           $1.to_i >= 3))
     end
 
+    # Returns whether this environment is using ActionPack
+    # version 2.3.6 (or greater, up until 3.0.0).
+    #
+    # @return [Boolean]
+    def ap_2_3_6?
+      require 'action_pack'
+      defined?(ActionPack::VERSION::MAJOR) &&
+        ActionPack::VERSION::MAJOR == 2 &&
+        ActionPack::VERSION::MINOR == 3 &&
+        ActionPack::VERSION::TINY >= 6
+    end
+
     # Returns an ActionView::Template* class.
     # In pre-3.0 versions of Rails, most of these classes
     # were of the form `ActionView::TemplateFoo`,