Bug #21323: irb fails to start with Namespace

• Status: Open
• Assignee: -
• Target version: -
• ruby -v: ruby 3.5.0dev (2025-05-10T07:50:29Z namespace-on-read-.. bd4f57f96b) +PRISM [x86_64-linux]
• Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN

[Eregon (Benoit Daloze)]

$ irb
irb(main):001> 6 * 7
=> 42

$ RUBY_NAMESPACE=1 irb
/home/eregon/prefix/ruby-master/bin/ruby: warning: Namespace is experimental, and the behavior may change in the future!
See doc/namespace.md for know issues, etc.
/home/eregon/prefix/ruby-master/lib/ruby/3.5.0+0/did_you_mean/core_ext/name_error.rb:11: warning: irb is not part of the default gems since Ruby 3.5.0. Install irb from RubyGems.
/home/eregon/prefix/ruby-master/lib/ruby/3.5.0+0/did_you_mean/core_ext/name_error.rb:11: warning: irb is not part of the default gems since Ruby 3.5.0. Install irb from RubyGems.
<internal:/home/eregon/prefix/ruby-master/lib/ruby/3.5.0+0/rubygems/core_ext/kernel_require.rb>:141:in 'Kernel#require': cannot load such file -- irb (LoadError)
Did you mean?  erb
	from <internal:/home/eregon/prefix/ruby-master/lib/ruby/3.5.0+0/rubygems/core_ext/kernel_require.rb>:141:in 'Kernel#require'
	from /home/eregon/prefix/ruby-master/lib/ruby/gems/3.5.0+0/gems/irb-1.15.2/exe/irb:7:in 'Namespace::Loader#require'
	from /home/eregon/prefix/ruby-master/lib/ruby/gems/3.5.0+0/gems/irb-1.15.2/exe/irb:7:in '<top (required)>'
	from /home/eregon/.rubies/ruby-master/bin/irb:25:in 'Kernel#load'
	from /home/eregon/.rubies/ruby-master/bin/irb:25:in 'Namespace::Loader#load'
	from /home/eregon/.rubies/ruby-master/bin/irb:25:in '<main>'
<internal:/home/eregon/prefix/ruby-master/lib/ruby/3.5.0+0/rubygems/core_ext/kernel_require.rb>:136:in 'Kernel#require': cannot load such file -- irb (LoadError)
Did you mean?  erb
	from <internal:/home/eregon/prefix/ruby-master/lib/ruby/3.5.0+0/rubygems/core_ext/kernel_require.rb>:136:in 'Kernel#require'
	from /home/eregon/prefix/ruby-master/lib/ruby/gems/3.5.0+0/gems/irb-1.15.2/exe/irb:7:in 'Namespace::Loader#require'
	from /home/eregon/prefix/ruby-master/lib/ruby/gems/3.5.0+0/gems/irb-1.15.2/exe/irb:7:in '<top (required)>'
	from /home/eregon/.rubies/ruby-master/bin/irb:25:in 'Kernel#load'
	from /home/eregon/.rubies/ruby-master/bin/irb:25:in 'Namespace::Loader#load'
	from /home/eregon/.rubies/ruby-master/bin/irb:25:in '<main>'
zsh: exit 1     RUBY_NAMESPACE=1 irb

[Eregon (Benoit Daloze)]

Looks somewhat similar, benchmark loads fine in main namespace but not in other namespace:

$ RUBY_NAMESPACE=1 ruby -ve 'require "benchmark"; p Benchmark::VERSION; ns = Namespace.new; File.write "ns.rb", "require :benchmark.to_s; p Benchmark::VERSION"; ns.require "./ns"'
ruby 3.5.0dev (2025-05-10T07:50:29Z namespace-on-read-.. bd4f57f96b) +PRISM [x86_64-linux]
ruby: warning: Namespace is experimental, and the behavior may change in the future!
See doc/namespace.md for know issues, etc.
"0.4.0"
/home/eregon/prefix/ruby-master/lib/ruby/3.5.0+0/did_you_mean/core_ext/name_error.rb:11: warning: benchmark is not part of the default gems since Ruby 3.5.0. Install benchmark from RubyGems.
/home/eregon/prefix/ruby-master/lib/ruby/3.5.0+0/did_you_mean/core_ext/name_error.rb:11: warning: benchmark is not part of the default gems since Ruby 3.5.0. Install benchmark from RubyGems.
<internal:/home/eregon/prefix/ruby-master/lib/ruby/3.5.0+0/rubygems/core_ext/kernel_require.rb>:141:in 'Kernel#require': cannot load such file -- benchmark (LoadError)
	from <internal:/home/eregon/prefix/ruby-master/lib/ruby/3.5.0+0/rubygems/core_ext/kernel_require.rb>:141:in 'Kernel#require'
	from /home/eregon/ns.rb:1:in 'Namespace::Loader#require'
	from /home/eregon/ns.rb:1:in '<top (required)>'
	from -e:1:in 'Namespace#require'
	from -e:1:in '<main>'
<internal:/home/eregon/prefix/ruby-master/lib/ruby/3.5.0+0/rubygems/core_ext/kernel_require.rb>:136:in 'Kernel#require': cannot load such file -- benchmark (LoadError)
	from <internal:/home/eregon/prefix/ruby-master/lib/ruby/3.5.0+0/rubygems/core_ext/kernel_require.rb>:136:in 'Kernel#require'
	from /home/eregon/ns.rb:1:in 'Namespace::Loader#require'
	from /home/eregon/ns.rb:1:in '<top (required)>'
	from -e:1:in 'Namespace#require'
	from -e:1:in '<main>'

[Eregon (Benoit Daloze)]

• Related to Bug #21324: Namespace loads RubyGems in root Namespace but it should not added