From: eregontp@... Date: 2017-11-30T10:25:06+00:00 Subject: [ruby-core:84001] [Ruby trunk Feature#14143] Thread.report_on_exception should be true by default Issue #14143 has been updated by Eregon (Benoit Daloze). @shevegen (Robert A. Heiler) wrote: > So to me, that first initial step, to find out how to deal with > threads in Ruby, was not trivial to find out. In that context > I agree with Benoit's comment "Nobody should have to remember" > which I think is a fine statement, in particular by people who > are new to ruby. It's not so difficult for more experienced, > older ruby people but for newcomers, making threads as simple > as possible would be good, IMO. I think it is also a problem even for experienced rubyists. I often forget to add Thread.{report or abort}_on_exception = true. It is not easy to remember that every Thread.new{} has to use these extra lines at the beginning or threads might crash silently with no easy way to debug. @headius was saying on IRC #jruby yesterday that he experiences this problem at least once a month. @enebo was talking about a similar scenario than yours: GUI programming with threads in Ruby is harder than it should because errors go unnoticed. ---------------------------------------- Feature #14143: Thread.report_on_exception should be true by default https://bugs.ruby-lang.org/issues/14143#change-68081 * Author: Eregon (Benoit Daloze) * Status: Open * Priority: Normal * Assignee: * Target version: ---------------------------------------- Extracted from #6647 to focus on the default value now that the feature is implemented. I strongly believe we should have Thread.report_on_exception = true by default. It only adds some extra stderr output for apps which let threads die, which is very rarely intended. If it is intended, then one can use Thread.current.report_on_exception = false to clarify it's OK for that thread to die and the failure is handled by the app on Thread#join. I enabled Thread.report_on_exception=true by default in ruby/spec, see https://github.com/ruby/spec/pull/517, the only cases needing Thread.current.report_on_exception=false are the specs testing report_on_exception itself and Thread#join/value/status/raise. Enabling it for test-all shows a fair amount of extra output and failures, which I would bet some of them are bugs in the tests (I already found one, r60854 & r60870), and other tests should simply more carefully test what they expect (for instance assert_raise() inside the Thread just around the code raising an exception and join the Thread). I am willing to help to reduce the extra output and failures in test-all, but I would like a OK from Matz to try enabling Thread.report_on_exception by default. Dear Matz, do you think it is reasonable to show exceptions killing threads on stderr by default, instead of silently swallowing them until Thread#join ? (if there is ever a Thread#join ..., often not or too late, when the rest of the application has crashed) -- https://bugs.ruby-lang.org/ Unsubscribe: