Bug #20337: Complex#inspect mutates the string returned by `real.inspect`

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x86_64-linux]
• Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN

[Eregon (Benoit Daloze)]

irb(main):001:0> n = Numeric.new
=> #<Numeric:0x00007f81b2308578>
irb(main):004:0> class Numeric; def inspect = super.freeze; end
=> :inspect
irb(main):006:0> Complex(n, 1).inspect
(irb):6:in `inspect': can't modify frozen String: "#<Numeric:0x00007f81b2308578>" (FrozenError)
        from (irb):6:in `<main>'                                                                        
        from /home/eregon/.rubies/ruby-3.2.2/lib/ruby/gems/3.2.0/gems/irb-1.6.2/exe/irb:11:in `<top (required)>'
        from /home/eregon/.rubies/ruby-3.2.2/bin/irb:25:in `load'                                       
        from /home/eregon/.rubies/ruby-3.2.2/bin/irb:25:in `<main>'             

It feels wrong to mutate the result of inspect at least in general, for instance true.inspect is frozen.

Discovered by https://github.com/ruby/spec/pull/1142

[Eregon (Benoit Daloze)]

Same for Complex#to_s.

[jeremyevans0 (Jeremy Evans)]

I submitted a pull request to fix this: https://github.com/ruby/ruby/pull/11657

• Status changed from Open to Closed

Applied in changeset git|9f574fa12f0cbe9d7aa4a11a6c7055ed32f02822.

---

Make Complex#{inspect,to_s} work correctly if real part #inspect returns frozen string

Make static f_format function take a non-frozen string to append
to.

This does not result in an additional allocation for #inspect,
but it does result in an additional allocation for #to_s.

Fixes [Bug #20337]