thoughtbot/paperclip — comment on commit 58671ebfffe3b03177d9ad248737932441fe4016
File: lib/paperclip.rb line 102
By cmaion:

This is incorrect when options[:swallow_stderr] is true and local_options[:swallow_stderr] is false: in this case, swallow_stderr is forced to be true when we would expect local_options[:swall_stderr] to take precedence.

I guess that you should fix it as follows:

- local_options = local_options.merge(:swallow_stderr => options[:swallow_stderr]) if !local_options[:swallow_stderr] && !options[:swallow_stderr].nil?
+ local_options = local_options.merge(:swallow_stderr => options[:swallow_stderr]) if local_options[:swallow_stderr].nil? && !options[:swallow_stderr].nil?