Issue #20250 has been updated by byroot (Jean Boussier). I had a quick look and this is very interesting. As far as I can tell `cached_object_id` for this Proc, so the most likely explanation is that some other part of the codebase is messing with the object flags. I'll try to dig deeper. ---------------------------------------- Bug #20250: Crash with "Object ID seen, but not in mapping table: proc" error https://bugs.ruby-lang.org/issues/20250#change-106657 * Author: zetter (Chris Zetter) * 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 ---------------------------------------- Hello, I experienced a crash which I was able to reliably reproduce with the following: ``` ruby require 'bundler/inline' gemfile(true) do source 'https://rubygems.org' gem 'activesupport', '7.1.3' end require 'active_support' logger = ActiveSupport::Logger.new('log/log.log', 1, 100 * 1024 * 1024) logger.formatter = proc {|_, _, _, message| "#{message}\n" } logger = ActiveSupport::TaggedLogging.new(logger) logger.tagged("TAG").info "hello" logger.tagged("TAG").info "hello" # usually crashes here GC.start # sometimes need to trigger crash with GC ``` It looks like this is caused by the interaction with the formatter proc and the tagged logging features of activesupport. Let me know if a more minimal example would be useful. I can reproduce this with: * ruby 3.3.0 on arm64-darwin23 * ruby 3.3.0 on x86_64-linux * latest ruby HEAD (5e12b75716) on arm64-darwin23 I cannot reproduce this on ruby 3.2.2. Thanks for any help ---Files-------------------------------- ruby-2024-02-09-092829.ips (13.2 KB) output.log (142 KB) crash_test_2.rb (465 Bytes) -- https://bugs.ruby-lang.org/