Question

Sorry for the strange title, I’m not really sure how to classify this issue. I’m in the process of updating some ruby code to 1.9.3, and am seeing some strange behavior. Distilling the issue, I get:

def convert(exception)
  raise exception.message
end

begin
  convert(StandardError.new(StandardError))
rescue => e
  puts e.class
end

In 1.9.2, the output is

StandardError

and in 1.9.3, te output is

RuntimeError

Looking though the ruby docs and release notes hasn’t really given me any clues as to what could be going on here, and any help is appreciated!

Answer 1

The issue seems to be that prior to 1.9.3, Exception#message returned an object of class Class, not String, which causes weird things to happen and it ends up raising an exception with an unexpected class (i.e., not RuntimeError).

This bug was fixed in this commit, and it is present in the 1.9.3 changelog.

Ultimately, you do want to raise exception, not raise exception.message.