Bug #21880: The ultra_safe mode of pstore bundled with Ruby 4.0 is broken.

• Status: Open
• Assignee: -
• Target version: -
• ruby -v: 4.0
• Backport: 3.2: REQUIRED, 3.3: REQUIRED, 3.4: REQUIRED, 4.0: REQUIRED

[s3fxn (s3 fxn)]

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

[bkuhlmann (Brooke Kuhlmann)]

ℹ️ This is also documented in Issue 22.

[nobu (Nobuyoshi Nakada)]

• Description updated (diff)

[nobu (Nobuyoshi Nakada)]

Fixed by ruby/pstore#36.

[nobu (Nobuyoshi Nakada)]

• Backport changed from 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN, 4.0: UNKNOWN to 3.2: REQUIRED, 3.3: REQUIRED, 3.4: REQUIRED, 4.0: REQUIRED

[nobu (Nobuyoshi Nakada)]

4.0 needs to backport gems/bundled_gems, and 3.2..3.4 need lib/pstore.rb.