From: john@... Date: 2016-09-13T07:36:35+00:00 Subject: [ruby-core:77259] [Ruby trunk Feature#6647] Exceptions raised in threads should be logged Issue #6647 has been updated by John Anderson. Responding to 2.4.0-preview2 announcement on ruby-core. I have the opinion that a good default for Thread.report_on_exception is $VERBOSE, with this mapping: nil - no reporting false (-W1) - report exception on thread GC which is likely to generate fewer warnings. Which will be less verbose. true (-W2 -w -v) - report exception on thread termination which is likely to generate extraneous warnings because threads haven't been joined yet. Which will be more verbose. ---------------------------------------- Feature #6647: Exceptions raised in threads should be logged https://bugs.ruby-lang.org/issues/6647#change-60491 * Author: Charles Nutter * Status: Closed * Priority: Normal * Assignee: Yukihiro Matsumoto ---------------------------------------- Many applications and users I have dealt with have run into bugs due to Ruby's behavior of quietly swallowing exceptions raised in threads. I believe this is a bug, and threads should always at least log exceptions that bubble all the way out and terminate them. The implementation should be simple, but I'm not yet familiar enough with the MRI codebase to provide a patch. The exception logging should be logged in the same way top-level exceptions get logged, but perhaps with information about the thread that was terminated because of the exception. Here is a monkey patch that simulates what I'm hoping to achieve with this bug: ```ruby class << Thread alias old_new new def new(*args, &block) old_new(*args) do |*bargs| begin block.call(*bargs) rescue Exception => e raise if Thread.abort_on_exception || Thread.current.abort_on_exception puts "Thread for block #{block.inspect} terminated with exception: #{e.message}" puts e.backtrace.map {|line| " #{line}"} end end end end Thread.new { 1 / 0 }.join puts "After thread" ``` Output: ``` system ~/projects/jruby $ ruby thread_error.rb Thread for block # terminated with exception: divided by 0 thread_error.rb:17:in `/' thread_error.rb:17 thread_error.rb:7:in `call' thread_error.rb:7:in `new' thread_error.rb:5:in `initialize' thread_error.rb:5:in `old_new' thread_error.rb:5:in `new' thread_error.rb:17 After thread ``` -- https://bugs.ruby-lang.org/ Unsubscribe: