Bug #22090: Enabling Ruby::Box breaks Marshal.load

• Status: Assigned
• Assignee: tagomoris (Satoshi Tagomori)
• Target version: -
• ruby -v: ruby 4.1.0dev (2026-05-31T10:35:05Z master 12c8599ffa) +PRISM [x86_64-linux]
• Backport: 3.3: UNKNOWN, 3.4: UNKNOWN, 4.0: UNKNOWN

[joker1007 (Tomohiro Hashidate)]

This is very simple.

class Foo
end

f = Marshal.dump(Foo.new)
Marshal.load(f)

No Ruby::Box

This code returns #<Foo:0x00007fdb9c744da0>.

---

Ruby::Box enabled

This code returns "undefined class/module Foo".

marshal_main.rb:5:in 'Marshal.load': undefined class/module Foo (ArgumentError)

p Marshal.load(f)
               ^
        from marshal_main.rb:5:in '<main>'

[joker1007 (Tomohiro Hashidate)]

• Subject changed from Enabling Ruby::Box breaks Marshal.load. to Enabling Ruby::Box breaks Marshal.load

[mame (Yusuke Endoh)]

• Status changed from Open to Assigned
• Assignee set to tagomoris (Satoshi Tagomori)