content_for.rb in roda-2.29.0

- old
+ new

@@ -42,11 +42,11 @@
 
       # Configure whether to append or overwrite if content_for
       # is called multiple times to set data. Overwrite is default, use
       # the :append option to append.
       def self.configure(app, opts = {})
-        app.opts[:append_content_for] = opts.fetch(:append, false)
+        app.opts[:append_content_for] = opts.fetch(:append, nil)
       end
 
       module InstanceMethods
         # If called with a block, store content enclosed by block
         # under the given key.  If called without a block, retrieve
@@ -69,9 +69,12 @@
             @_content_for ||= {}
 
             if append
               (@_content_for[key] ||= []) << value
             else
+              if @_content_for[key] && append.nil?
+                RodaPlugins.warn "Attempt to set content_for with same key.  This currently overwrites the existing content_for for #{key}.  In Roda 3, it will start appending to the existing content_for by default.  Use the :append => false option to the content_for plugin to keep the existing behavior."
+              end
               @_content_for[key] = value
             end
           elsif @_content_for && (value = @_content_for[key])
             if append
               value = value.join