From: ko1@atdot.net
To: ruby-core@ruby-lang.org
Subject: [ruby-core:72372] [Ruby trunk - Bug #11822] Semantics of Queue#pop after close are wrong
Date: Sat, 19 Dec 2015 01:39:53 +0000 [thread overview]
Message-ID: <redmine.journal-55663.20151219013952.f430690b2cddaccc@ruby-lang.org> (raw)
In-Reply-To: redmine.issue-11822.20151215160530@ruby-lang.org
Issue #11822 has been updated by Koichi Sasada.
Petr Chalupa wrote:
> Could you clarify for me following cases: What does pop do when called on empty closed queue? What does close do about already blocked threads when it's empty?
> The documentation does not specifies this.
> What does pop do when called on empty closed queue?
returns nil.
> What does close do about already blocked threads when it's empty?
I assume 'already blocked threads' are consumer threads.
They are resumed, and get nil.
You can verify with code.
```ruby
q = Queue.new
q.close
p q.pop
```
```ruby
q = Queue.new
Thread.new{
sleep 1
q.close
}
p q.pop
```
----------------------------------------
Bug #11822: Semantics of Queue#pop after close are wrong
https://bugs.ruby-lang.org/issues/11822#change-55663
* Author: Charles Nutter
* Status: Open
* Priority: Normal
* Assignee: Koichi Sasada
* ruby -v:
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN
----------------------------------------
Current test/ruby/thread/test_queue.rb test_close has the following assertion that seems wrong to me:
```ruby
def test_close
[->{Queue.new}, ->{SizedQueue.new 3}].each do |qcreate|
q = qcreate.call
assert_equal false, q.closed?
q << :something
assert_equal q, q.close
assert q.closed?
assert_raise_with_message(ClosedQueueError, /closed/){q << :nothing}
assert_equal q.pop, :something # <<< THIS ONE
assert_nil q.pop
assert_nil q.pop
# non-blocking
assert_raise_with_message(ThreadError, /queue empty/){q.pop(non_block=true)}
end
end
```
Once a queue is closed, I don't think it should ever return a result anymore. The queue should be cleared and pop should always return nil.
In r52691, ko1 states that "deq'ing on closed queue returns nil, always." This test does not match that behavior.
--
https://bugs.ruby-lang.org/
next prev parent reply other threads:[~2015-12-19 1:07 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <redmine.issue-11822.20151215160530@ruby-lang.org>
2015-12-15 16:05 ` [ruby-core:72149] [Ruby trunk - Bug #11822] [Open] Semantics of Queue#pop after close are wrong headius
2015-12-15 16:58 ` [ruby-core:72150] [Ruby trunk - Bug #11822] " headius
2015-12-15 17:48 ` [ruby-core:72152] " headius
2015-12-15 17:52 ` [ruby-core:72155] " headius
2015-12-15 23:47 ` [ruby-core:72164] " ko1
2015-12-16 7:39 ` [ruby-core:72178] " funny.falcon
2015-12-18 5:32 ` [ruby-core:72357] " ko1
2015-12-18 18:41 ` [ruby-core:72369] " email
2015-12-19 1:39 ` ko1 [this message]
2015-12-19 13:37 ` [ruby-core:72380] " email
2015-12-19 14:37 ` [ruby-core:72382] " headius
2015-12-19 15:01 ` [ruby-core:72383] " email
2015-12-19 15:27 ` [ruby-core:72386] " headius
2015-12-19 15:29 ` [ruby-core:72387] " headius
2015-12-20 8:54 ` [ruby-core:72408] " funny.falcon
2016-01-25 18:21 ` [ruby-core:73429] " Andrew Vit
2017-01-31 7:12 ` [ruby-core:79334] [Ruby trunk Bug#11822][Closed] " ko1
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