JSON.pretty_generate generates wrong format json output to MRI for at least an empty hash version 9.4.0.0

[tqtu]

Code:

require 'json'
puts "With empty hash"
puts JSON.pretty_generate({})
puts "With empty hash in child"
puts JSON.pretty_generate({"empty": {}})

Output: jruby -v hello.rb

jruby 9.4.0.0 (3.1.0) 2022-11-23 95c0ec159f Java HotSpot(TM) 64-Bit Server VM 25.202-b08 on 1.8.0_202-b08 +jit [x86_64-darwin]
With empty hash
{
}
With empty hash in child
{
  "empty": {
}
}

The indentation is incorrect.
CC: @headius

[headius]

Thank you for the report!

[headius]

Likely caused by changes in #449.

[headius]

Fix in #517.

[mrckzgl]

We experience the empty hash problem also with MRI ruby ruby 3.2.1 (2023-02-08 revision 31819e82c8) [x86_64-linux] and jruby jruby 9.4.1.0 (3.1.0) 2023-02-07 237d5fa5f4 Java HotSpot(TM) 64-Bit Server VM 15.0.2+7-27 on 15.0.2+7-27 +jit [x86_64-linux] while using the json/pure variant. Should I open a new issue for this?