[Dancer-users] why does "warn" fail?

[Brian E. Lozier]

As a perl veteran I am used to using the built-in "warn" function to
write to STDERR.  Under mod_perl/Apache this prints to the web
server's error log.  Using my dancer app like this:

plackup -L Shotgun app.pl

If I have a "warn" anywhere in my app, I get an error message:

Error trace

status code needs to be an integer greater than or equal to 100 at
/usr/local/lib/perl5/site_perl/5.12.2/Plack/Middleware/StackTrace.pm
line 27

However, if I print STDERR "msg"; that works.  My question is: what
happened to warn?  Can it be fixed so that it writes to STDERR instead
of triggering an error message?

I know about the "warning" function but it's really hard to change 10
years of muscle memory!

Thanks,
Brian