Issue #20779 has been updated by luke-gru (Luke Gruber). I managed to track down the issue, it's a pretty simple fix. My PR is here: https://github.com/ruby/ruby/pull/12441 ---------------------------------------- Bug #20779: Un-rescuable thread creation limit on Mac https://bugs.ruby-lang.org/issues/20779#change-111159 * Author: hms (Hal Spitz) * Status: Open * ruby -v: 3.3.5 * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- Thread.new will hang the ruby process once past the OSX limit. It does not appear that's possible to trap and rescue failed thread creation. It seems the Mac has a limit to the number of threads it supports and googling the issue suggests the limit has been known to change with hardware and OS releases. While I hit the thread creation limit due to a bug in my code and the number of threads that I was attempting to create (12,250+) is an unlikely use-case, I am hoping it would be possible to turn this into a rescuable error. While I'm reporting this on 3.3.5, I have tested the issue and the inability to rescue back to 3.3.1. (Thanks to @raels for being a great second set of eyes to make sure I wasn't doing anything goofy / wrong before making this report. Also, another callout and thanks to both @eregon and @bensheldon over at concurrent-ruby for the unbelievably quick and helpful response to my initial bug report over there). ---Files-------------------------------- hang.rb (713 Bytes) -- https://bugs.ruby-lang.org/