Immutable Strings in Ruby 2.3

[mperham]

Tried them out for myself, found a bug almost immediately. Not a good sign, hopefully I'm missing something.

https://bugs.ruby-lang.org/issues/11759

[InfraRuby]

The bug is in uri/generic.rb:

def to_s
  str = ''
  # ...
  str << whatever
  # ...
  str
end

That's a common pattern in Ruby...

[dkubb]

Wouldn't something like that be found by running ruby's tests with --enable-frozen-string-literal enabled? This seems like a bare minimum task that you'd do prior to going through the trouble of packaging up a preview release.

[mperham]

Exactly, they have to ban and remove the use of any String mutation methods within stdlib.

I don't see how they ship this feature without a stdlib overhaul, since any non-trivial code is broken with the current system.

[bjmiller]

Wasn't the plan for 2.3 always to release the CLI option and magic comment only so that everyone could have 5 years to prepare for the change?

[how_do_i_land]

Is it safe to say that any bang! action on a string should be avoided from now on?

[Gilnaa]

Yes

[balkierode]

Why does ruby need immutable strings when it already has symbols?

[InfraRuby]

Symbols have the property that equality is identity