Do not check HamlTemplate inside haml engine check

Author: k0kubun

sinatra-contrib/lib/sinatra/capture.rb

@@ -86,7 +86,7 @@ module Capture
 
     def capture(*args, &block)
       return block[*args] if ruby?
-      if haml?
+      if haml? && Tilt[:haml] == Tilt::HamlTemplate
         buffer = Haml::Buffer.new(nil, Haml::Options.new.for_buffer)
         with_haml_buffer(buffer) { capture_haml(*args, &block) }
       else

sinatra-contrib/lib/sinatra/content_for.rb

@@ -174,7 +174,7 @@ def clear_content_for(key)
     # for <tt>:head</tt>.
     def yield_content(key, *args, &block)
       if block_given? && !content_for?(key)
-        haml? ? capture_haml(*args, &block) : yield(*args)
+        (haml? && Tilt[:haml] == Tilt::HamlTemplate) ? capture_haml(*args, &block) : yield(*args)
       else
         content = content_blocks[key.to_sym].map { |b| capture(*args, &b) }
         content.join.tap do |c|

sinatra-contrib/lib/sinatra/engine_tracking.rb

@@ -29,10 +29,9 @@ def erubis?
       erb? && Tilt[:erb] == Tilt::ErubisTemplate
     end
 
-    # @return [Boolean] Returns true if current engine is `:haml` and
-    # `Tilt[:haml]` is set to `Tilt::HamlTemplate`.
+    # @return [Boolean] Returns true if current engine is `:haml`.
     def haml?
-      @current_engine == :haml && Tilt[:haml] == Tilt::HamlTemplate
+      @current_engine == :haml
     end
 
     # @return [Boolean] Returns true if current engine is `:sass`.