Issue #20188 has been updated by fxn (Xavier Noria). Are you guys sure `defined?` depends on the thread? In this test running in 3.3 I don't seem to reproduce: ```ruby $up = Queue.new $down = Queue.new File.write('/tmp/bar.rb', <<~RUBY) Bar = 1 $up << true $down.pop p defined?(Bar) RUBY autoload :Bar, '/tmp/bar.rb' t = Thread.new { Bar } $up.pop p defined?(Bar) $down << true t.join ``` I get two "constant"s printed. ---------------------------------------- Bug #20188: `Module#const_source_location` returns wrong information when real constant was defined but autoload is still ongoing https://bugs.ruby-lang.org/issues/20188#change-106356 * Author: byroot (Jean Boussier) * Status: Open * Priority: Normal * ruby -v: ruby 3.3.0 (2023-12-25 revision 5124f9ac75) [arm64-darwin23] * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- Ref: https://github.com/fxn/zeitwerk/issues/281 `const_source_location` keeps returning the location of the `autoload` call, even after the real constant was defined. It only starts returning the real constant location once the autoload was fully completed. ```ruby # /tmp/autoload.rb File.write("/tmp/const.rb", <<~RUBY) module Const LOCATION = Object.const_source_location(:Const) end RUBY autoload :Const, "/tmp/const" p Const::LOCATION ``` Expected Output: ```ruby ["/tmp/const.rb", 1] ``` Actual Output: ```ruby ["/tmp/autoload.rb", 8] ``` Potential patch: https://github.com/ruby/ruby/pull/9549 -- https://bugs.ruby-lang.org/