Bug #22282: $VERBOSE and $DEBUG assignments have no effect under RUBY_BOX=1

• Status: Open
• Assignee: -
• Target version: -
• ruby -v: ruby 4.1.0dev (2026-08-30T19:29:13Z master 3aa34522c1) [arm64-darwin27]
• Backport: 3.3: UNKNOWN, 3.4: UNKNOWN, 4.0: UNKNOWN

[hsbt (Hiroshi SHIBATA)]

Assigning to $VERBOSE or $DEBUG does nothing when RUBY_BOX=1 is set. The assignment lands in the box-local global variable table instead of reaching verbose_setter/debug_setter, so warnings are never silenced or enabled, and the alias variables keep reporting the unchanged interpreter flag.

$ ruby -e '$VERBOSE = nil; p [$VERBOSE, $-v, $-W]'
[nil, nil, 0]
$ RUBY_BOX=1 ruby -e '$VERBOSE = nil; p [$VERBOSE, $-v, $-W]'
[nil, true, 2]

$ ruby -e '$VERBOSE = nil; warn "printed"'
$ RUBY_BOX=1 ruby -e '$VERBOSE = nil; warn "printed"'
printed

$ RUBY_BOX=1 ruby -e '$DEBUG = true; p [$DEBUG, $-d]'
[true, false]

This silently breaks the old, $VERBOSE = $VERBOSE, nil; ...; $VERBOSE = old idiom that RubyGems, Bundler, Rails and many test suites rely on. ruby -W0 still works, because it sets the flag before the main box exists.

Reproduced on master (3aa34522c1) and on released 4.0.6. Found while running the RubyGems and Bundler suites under RUBY_BOX=1 (#22275).

Patch: https://github.com/ruby/ruby/pull/18579

[hsbt (Hiroshi SHIBATA)]

• Related to Misc #22275: Ruby::Box support plan for RubyGems and Bundler added