Issue #14681 has been updated by ioquatix (Samuel Williams).


Excuse my ignorance, but if you call write, why can't you just directly invoke `::write`?  Why do you need to do `rb_thread_io_blocking_region`?

----------------------------------------
Bug #14681: `syswrite': stream closed in another thread (IOError)
https://bugs.ruby-lang.org/issues/14681#change-71600

* Author: ioquatix (Samuel Williams)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: 2.5.0
* Backport: 2.3: UNKNOWN, 2.4: UNKNOWN, 2.5: UNKNOWN
----------------------------------------
Perhaps related to https://bugs.ruby-lang.org/issues/13632

Here is a sample to reproduce the issue.

```
#!/usr/bin/env ruby

require 'thread'

puts RUBY_VERSION

100.times.collect do
	Thread.new do
		input, output = IO.pipe
		
		worker = Thread.new do
			sleep(0.1)
			output.syswrite('.')
		end
		
		input.read(1)
		
		input.close
		output.close
		worker.join
	end
end.each(&:join)
```

If you run this, you will get output like so:

```
2.5.0
#<Thread:0x00007fb7a4956ee8@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:11 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a50bb468@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:11 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a4964250@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:11 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a49386f0@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:11 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a493ab08@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:11 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a495fb88@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:8 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a50bbb98@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:11 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a4948820@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:11 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a4939820@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:11 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a486a458@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:8 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a4860020@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:11 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a4970258@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:11 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a4973f48@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:11 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a4948618@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:11 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a495f728@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:8 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a495f868@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:8 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a4848628@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:8 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a4843858@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:8 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a4809400@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:8 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a5085278@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:8 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a495e0f8@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:8 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a48417d8@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:11 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a5037c80@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:8 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a4948398@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:11 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a4948c30@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:11 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a4939b18@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:11 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a4957500@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:11 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a480a9b8@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:8 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a5036d30@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:8 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a5085c50@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:8 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a495e2b0@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:8 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a495f070@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:8 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a495e6e8@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:8 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a49572d0@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:11 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a495e580@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:8 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a494a350@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:11 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a4811060@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:8 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a50842b0@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:8 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a494bb10@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:11 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a493ae00@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:11 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a495e878@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:8 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a494be30@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:11 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a4809c70@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:8 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a480a4e0@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:8 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a50b90f0@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:11 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
#<Thread:0x00007fb7a4965600@/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:8 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
Traceback (most recent call last):
        1: from /private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `block (3 levels) in <main>'
/private/var/folders/3x/tvygzl0s65520b6t4tzqbt980000gn/T/16789369-c982-4cbc-a0b3-c836af60bf03:13:in `syswrite': stream closed in another thread (IOError)
Exited with status 1 after 0.291 seconds
```

However, you can clearly see from the order of the sample code it's not possible for such an error to occur. `#close` is only invoked after a successful `#read` which is only possible after a successful `#write`. Yet, the error implies that the write failed because it was already closed.



-- 
https://bugs.ruby-lang.org/

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