Bug #17617: When a Ractor's incoming port is closed, Ractor.receive_if does not raise Ractor::ClosedError, but instead blocks indefinitely

• Status: Assigned
• Assignee: ko1 (Koichi Sasada)
• Target version: -
• ruby -v: ruby 3.3.0dev (2023-11-13T21:00:10Z master e8ab3f7010) [x86_64-darwin23]
• Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN

[dazuma (Daniel Azuma)]

If Ractor#close_incoming is called on a Ractor, any pending Ractor.receive call will raise Ractor::ClosedError. However, any pending Ractor.receive_if call will not; instead, it never returns.

r1 = Ractor.new do
  Ractor.receive
rescue => e
  e
end
r1.close_incoming
result = r1.take
puts "**** taken: #{result}"  # displays the Ractor::ClosedError

r2 = Ractor.new do
  Ractor.receive_if { true }
  puts "**** never reaches here"
rescue => e
  puts "**** never reaches here"
  e
end
r2.close_incoming
puts "**** hangs here..."
r2.take
puts "**** never reaches here"

This was tested against both 3.0.0 and 3.1.0 head, with the same result.

% ruby -v
ruby 3.1.0dev (2021-02-09T13:22:37Z master e7a831de8e) [x86_64-darwin20]

% ruby -v
ruby 3.0.0p0 (2020-12-25 revision 95aff21468) [x86_64-darwin20

I have also tried including sleep statements to force the Ractor.receive_if to execute both before and after the Ractor#close_incoming call. The result is the same either way. receive_if hangs regardless of whether the incoming port is already closed when receive_if is invoked, or whether the port is closed while the receive_if is already blocking.

[mame (Yusuke Endoh)]

• Assignee set to ko1 (Koichi Sasada)

[dazuma (Daniel Azuma)]

• ruby -v changed from ruby 3.1.0dev (2021-02-09T13:22:37Z master e7a831de8e) [x86_64-darwin20] to ruby 3.3.0dev (2023-11-13T21:00:10Z master e8ab3f7010) [x86_64-darwin23]

Retested, still reproduces on 3.2.2 and 3.3.0-dev as of 2023 Nov 13.

[hsbt (Hiroshi SHIBATA)]

• Status changed from Open to Assigned