Ruby 1.9.3p392 (and probably any 1.9 Ruby) incorrectly stringify RbVmomi::Fault in raise

[slippycheeze]

One of the semantic changes in Ruby 1.9 was to start using methods like String#to_str blindly, and relying on the MethodMissing exception to determine that the facility isn't supported.

This, in turn, leads to calling raise on an explicitly created instance of RbVmomi::Fault (from 1.6.0) raising a RuntimeError instance - because RbVmomi::Fault delegates to_str to the @fault member, and that responds with a string, so Kernel#raise treats it as if you called raise RbVmomi::Fault.new(...).to_s instead.

1.9.3p392 :002 > begin
1.9.3p392 :003 >     raise RbVmomi::Fault.new('foo', 'bar')
1.9.3p392 :004?>   rescue Exception => e
1.9.3p392 :005?>     e.class
1.9.3p392 :006?>   end
 => RuntimeError

I discovered this in a test where we stubbed out raising the exception class, but it would also apply to all the instances in the gem that raise on a manually created RbVmomi::Fault class - they will throw RuntimeError, and bypass explicit catching in at least some versions of Ruby 1.9.3.

The easiest resolution to this is to exclude to_str from the method_missing implementation, allowing it to raise the traditional NoMethodError exception, and through that cause the Ruby runtime to behave as expected.