Issue #16509 has been updated by Marthyn (Marthyn Olthof). **Ruby 2.7.0** ``` irb(main):002:1* EventMachine.run do irb(main):003:1* EM.add_periodic_timer(1) { puts "Tick ..." } irb(main):004:2* EM.add_timer(3) do irb(main):005:2* puts "I waited 3 seconds" irb(main):006:2* EM.stop_event_loop irb(main):007:1* end irb(main):008:0> end Tick ... Tick ... I waited 3 seconds => nil irb(main):009:0> irb(main):010:1* Thread.new do irb(main):011:2* EventMachine.run do irb(main):012:2* EM.add_periodic_timer(1) { puts "Tick ..." } irb(main):013:3* EM.add_timer(3) do irb(main):014:3* puts "I waited 3 seconds" irb(main):015:3* EM.stop_event_loop irb(main):016:2* end irb(main):017:1* end irb(main):018:0> end => #<Thread:0x00007f8e4ea08c08 (irb):9 run> irb(main):019:0> Tick ... Tick ... I waited 3 seconds ``` Same result **Ruby 2.6.5** ``` irb(main):002:0> EventMachine.run do irb(main):003:1* EM.add_periodic_timer(1) { puts "Tick ..." } irb(main):004:1> EM.add_timer(3) do irb(main):005:2* puts "I waited 3 seconds" irb(main):006:2> EM.stop_event_loop irb(main):007:2> end irb(main):008:1> end Tick ... Tick ... I waited 3 seconds Tick ... => nil irb(main):009:0> irb(main):010:0> Thread.new do irb(main):011:1* EventMachine.run do irb(main):012:2* EM.add_periodic_timer(1) { puts "Tick ..." } irb(main):013:2> EM.add_timer(3) do irb(main):014:3* puts "I waited 3 seconds" irb(main):015:3> EM.stop_event_loop irb(main):016:3> end irb(main):017:2> end irb(main):018:1> end => #<Thread:0x00007fa03f108d80@(irb):10 run> irb(main):019:0> Tick ... Tick ... I waited 3 seconds Tick ... ``` No indent. ---------------------------------------- Bug #16509: puts from EM within a thread seem to be missing linefeed when run in ruby 2.7.0 console https://bugs.ruby-lang.org/issues/16509#change-83932 * Author: jmaino (Jim Maino) * Status: Open * Priority: Normal * Assignee: * Target version: * ruby -v: 2.7.0 * Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN ---------------------------------------- This is strange, and I'm hoping I explain it sufficiently - but I've upgraded to ruby 2.7.0 and I'm seeing missing linefeeds in puts outputs from EM that's within a thread. I did not see this problem when running in ruby 2.6.5's console output - it seems to be related to my move to 2.7.0. I've simplified this to reproduce this as folllows. If I run the following EM without being inside of a thread, then I get an OK output - example: irb(main):042:1* EventMachine.run do irb(main):043:1* EM.add_periodic_timer(1) { puts "Tick ..." } irb(main):044:1* irb(main):045:2* EM.add_timer(3) do irb(main):046:2* puts "I waited 3 seconds" irb(main):047:2* EM.stop_event_loop irb(main):048:1* end irb(main):049:0> end Tick ... Tick ... I waited 3 seconds => nil Note all of the strings that are output from the puts commands within the EM loop are fully left-justified in the output. But if I wrap this in a thread, the output lines appear to be missing the linefeed, but do have the CR - such that the successive puts strings are not left justified as they sequence, and build from the X-offset that ended the previous puts string output. irb(main):001:1* Thread.new do irb(main):002:2* EventMachine.run do irb(main):003:2* EM.add_periodic_timer(1) { puts "Tick ..." } irb(main):004:2* irb(main):005:3* EM.add_timer(3) do irb(main):006:3* puts "I waited 3 seconds" irb(main):007:3* EM.stop_event_loop irb(main):008:2* end irb(main):009:1* end irb(main):010:0> end => #<Thread:0x000055cf1a8482c8 (irb):1 run> irb(main):011:0> Tick ... _________________________Tick ... _______________________________ I waited 3 seconds Is there something that's known to have changed that is causing this? Can others reproduce this as well? I can't tell is this is EM's or ruby's - so any help would really be appreciated. However, the folks over at eventmachine think this belongs to ruby and not themselves. I only see this from puts statements within the EM loop within a Thread. If the wrapping Thread is not there, there's no issue. If there's just a sequence of puts in a Thread and no EM loop, there's no issue. It seems as if there's something about the combo of a Thread wrapping an EM loop that's making the underlying puts misbehave. Thanks, -Jim -- https://bugs.ruby-lang.org/ Unsubscribe: <mailto:ruby-core-request / ruby-lang.org?subject=unsubscribe> <http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>