Issue #21880 has been reported by s3fxn (s3 fxn). ---------------------------------------- Bug #21880: The ultra_safe mode of pstore bundled with Ruby 4.0 is broken. https://bugs.ruby-lang.org/issues/21880 * Author: s3fxn (s3 fxn) * Status: Open * ruby -v: 4.0 * Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN, 4.0: UNKNOWN ---------------------------------------- here is the reproduction code. $ ruby -v ruby 4.0.1 (2026-01-13 revision e04267a14b) +PRISM [x86_64-linux] $ cat pstore.rb #!/usr/bin/env ruby require "bundler/inline" gemfile do source "https://rubygems.org" if ENV['DEBUG'] gem "pstore", "0.1.4" else gem "pstore" end end db = PStore.new("pstore.db") db.ultra_safe = true db.transaction do puts db["now"] = Time.now end $ ruby pstore.rb 2026-02-15 04:49:31 +0000 /home/s3fxn/.rubies/ruby-4.0.1/lib/ruby/gems/4.0.0/gems/pstore-0.2.0/lib/pstore.rb:676:in 'Ractor.make_shareable': Proc's self is not shareable: #<Proc:0x0000749f688df078 /home/s3fxn/.rubies/ruby-4.0.1/lib/ruby/gems/4.0.0/gems/pstore-0.2.0/lib/pstore.rb:673> (Ractor::IsolationError) from /home/s3fxn/.rubies/ruby-4.0.1/lib/ruby/gems/4.0.0/gems/pstore-0.2.0/lib/pstore.rb:676:in 'PStore#on_windows?' from /home/s3fxn/.rubies/ruby-4.0.1/lib/ruby/gems/4.0.0/gems/pstore-0.2.0/lib/pstore.rb:685:in 'PStore#save_data' from /home/s3fxn/.rubies/ruby-4.0.1/lib/ruby/gems/4.0.0/gems/pstore-0.2.0/lib/pstore.rb:575:in 'PStore#transaction' from pstore.rb:14:in '<main>' $ DEBUG=1 ruby pstore.rb 2026-02-15 04:49:53 +0000 -- https://bugs.ruby-lang.org/