I am using
(flori@lambda:~ 0)$ ruby -v; gem list activesupport|grep ^a
ruby 1.8.5 (2006-12-04 patchlevel 2) [i686-linux]
I experienced some problems with using Ruby's Logger class, all formatting was missing from the output after the first few lines.
In active_support/clean_logger.rb the method ::Logger#format_message is silently patched and broken, even though under 1.8.5 a Logger#formatter= method exists, that can be used to choose your own formatter implementation. In the comment there are some bad reasons given, why this is necessary. This makes it impossible to use Ruby's Logger class like it was intended to for all other clients.
I don't get it: Why doesn't Rails use its own Logger class, that may or may not derive from ::Logger, instead of breaking Ruby's standard library? It took me quite some time to track down this problem, and the reckless behavior that caused it.
Zed Shaw seemed to have exactly the same problem more than a year ago (or is this a repeated instance of it?):
You can go read his rant, so I don't have to repeat it all. Please fix this bug in some sustainable way. Thanks for listening.