Bug #15644
closedThreadsWait problems with Thread#report_on_exception
Description
Using ThreadsWait with Thread.report_on_exception is confusing.
ThreadsWait spawns a new thread for waiting on a thread:
# thwait.rb:87
def join_nowait(*threads)
threads.flatten!
@threads.concat threads
for th in threads
Thread.start(th) do |t|
begin
t.join
ensure
@wait_queue.push t
end
end
end
end
The t.join
in ThreadsWait
will re-raise the exceptions that happen in the thread being waited on.
If the thread being waited on was using report_on_exception = false
, the wait thread will report the exception and the report_on_exception = false
effectively did nothing, as you still got an exception report.
If the thread was using report_on_exception = true
, both threads will report the exception, so you get it twice.
I think this could be fixed by always setting report_on_exception = false
for the wait thread.
Example 1¶
require 'thwait'
thread = Thread.new do
Thread.current.report_on_exception = false
sleep 1
raise "Foo"
end
ThreadsWait.all_waits(thread) do |terminated_thread|
puts "Thread #{terminated_thread} terminated"
end
Expected result¶
No exception reports
Actual result¶
The wait thread will report the exception:
#<Thread:0x00007fa57d092d68@/Users/user/.rbenv/versions/2.6.1/lib/ruby/2.6.0/thwait.rb:91 run> terminated with exception (report_on_exception is true):
Example 2¶
require 'thwait'
thread = Thread.new do
sleep 1
raise "Foo"
end
ThreadsWait.all_waits(thread) do |terminated_thread|
puts "Thread #{terminated_thread} terminated"
end
Expected result¶
One exception report
Actual result¶
Two exception reports:
#<Thread:0x00007f9f83053320@test.rb:3 run> terminated with exception (report_on_exception is true):
#<Thread:0x00007f9f830530a0@/Users/user/.rbenv/versions/2.6.1/lib/ruby/2.6.0/thwait.rb:91 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
Updated by jeremyevans0 (Jeremy Evans) about 5 years ago
- Status changed from Open to Assigned
- Assignee set to keiju (Keiju Ishitsuka)
I agree this is a bug that should be fixed. I have submitted a pull request to fix it: https://github.com/ruby/thwait/pull/1
Updated by jeremyevans0 (Jeremy Evans) over 2 years ago
- Status changed from Assigned to Closed