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Bug #11153
closedDefining singleton methods using `class << self` sometimes fails when using threads
Status:
Closed
Assignee:
-
Target version:
-
ruby -v:
ruby 2.2.2p95 (2015-04-13 revision 50295) [x86_64-darwin14]
Description
Defining singleton methods using this syntax occasionally produces unexpected results when run in parallel with multiple threads:
class << obj
def method_one
end
def method_two
end
end
Sometimes not all of the methods are defined, leading to this result:
obj.respond_to?(:method_one) # => true
obj.respond_to?(:method_two) # => false
Here is a short script that demonstrates the bug.
require "thread"
def define_singleton_methods_in_thread
Thread.new do
100_000.times do
obj = Object.new
class << obj
def one
end
def two
end
def three
end
end
puts "FAIL" unless obj.respond_to?(:three)
end
end
end
# Test with 2 threads
2.times.map { define_singleton_methods_in_thread }.map(&:join)
On my machine this script prints "FAIL" 3 times.
I am able to reproduce this bug in 2.0.0-p451, 2.1.6, 2.2.2, and the current ruby_2_2 branch. I cannot reproduce in trunk.
More information here: https://github.com/net-ssh/net-ssh/pull/240
Updated by mattbrictson (Matt Brictson) over 9 years ago
This may be a duplicate of #10871.
Updated by jeremyevans0 (Jeremy Evans) over 5 years ago
- Status changed from Open to Closed
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