Ruby variable initialisation

Question

In the following code there is an execution path where "bar" is not set before it is tested, is doing this safe in Ruby? will "bar" have a default initialisation?

if foo
  bar = true
end

if bar
  puts "true"
end

Answer 1

Yes

Yes, it is safe, in the sense that the worst that can happen when an uninitialized local is referenced is that a NameError exception will be raised.

Yours is a bit of a special-case, actually. Since the parser will have seen bar before it is referenced, then the method will not raise NameError, even if foo is false, but rather the value of bar will be nil.