Ruby

StringIO doesn't appear to handle chilled strings in a backwards-compatible way after 12be40ae

require "stringio"

sio = StringIO.new("")
sio.write("hello")

When not specifying a value for frozen-string-literal, the empty string is chilled so I would expect to get a warning but also expect the write to complete.

Instead, the write fails as if the string is frozen:

ruby 3.4.0dev (2024-03-23T16:40:17Z master 8265a7531f) [x86_64-linux]
./issue-stringio-frozen.rb:8:in 'StringIO#write': not opened for writing (IOError)
        from ./issue-stringio-frozen.rb:8:in '<main>'

cc @byroot (Jean Boussier) @etienne (Étienne Barrié)