[ruby-core:122098] [Ruby Bug#21339] Namespace: `RubyVM::InstructionSequence.load_iseq` isn't called for the root namespace

14 May 2025

      Issue #21339 has been reported by byroot (Jean Boussier).

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Bug #21339: Namespace: `RubyVM::InstructionSequence.load_iseq` isn't called for the root namespace
https://bugs.ruby-lang.org/issues/21339

* Author: byroot (Jean Boussier)
* Status: Assigned
* Assignee: tagomoris (Satoshi Tagomori)
* ruby -v: ruby 3.5.0dev (2025-05-14T12:41:46Z master b5575a80bc) +PRISM [arm64-darwin24]
* Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN
----------------------------------------
```ruby
File.write("/tmp/compile-cache.rb", <<~'RUBY')
  class << RubyVM::InstructionSequence
    def load_iseq(path)
      p [:load_iseq, path]
      RubyVM::InstructionSequence.compile_file(path)
    end
  end
RUBY
File.write("/tmp/test-file.rb", "")

puts "main:"
require "/tmp/compile-cache.rb"
require "/tmp/test-file.rb"

if ENV["RUBY_NAMESPACE"]
  puts "namespace:"
  ns = Namespace.new
  ns.require("/tmp/compile-cache.rb")
  ns.require("/tmp/test-file.rb")
end
```

Expected behavior:

I would expect `load_iseq` to be invoked both in the root namespace and the user namespace when `RUBY_NAMESPACE=1`.

Actual behavior:

Somehow it's only invoked in the user namespace:

```bash
main:
[:compile_cache_setup]
[:load_iseq, "/tmp/test-file.rb"]
```

```bash
main:
[:compile_cache_setup]
namespace:
[:compile_cache_setup]
[:load_iseq, "/tmp/test-file.rb"]
```

But I don't understand why.

-- 
https://bugs.ruby-lang.org/