From: ruby-core@...
Date: 2014-11-30T05:34:27+00:00
Subject: [ruby-core:66583] [ruby-trunk - Bug #10167] Prime#include?(mod)	hangs up

Issue #10167 has been updated by Marc-Andre Lafortune.

Assignee set to Yuki Sonoda

Instead of aliasing `include?` to `prime?`, I'd recommend instead to restore it:

     Prime.define_singleton_method(:include?, Module.instance_method(:include?))
     Prime.include?(Enumerable) # => true

Probably won't be super useful, but still beats an infinite loop :-)

Assigning to yugui, although I have not seen any activity from her in over a year on the mailing list?

----------------------------------------
Bug #10167: Prime#include?(mod) hangs up
https://bugs.ruby-lang.org/issues/10167#change-50198

* Author: Kenichi Saita
* Status: Open
* Priority: Normal
* Assignee: Yuki Sonoda
* Category: lib
* Target version: current: 2.2.0
* ruby -v: ruby 2.1.2p95 (2014-05-08 revision 45877) [x86_64-linux]
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
----------------------------------------
We expect `Prime` class implements `Module#include?(mod)`.  But `Prime#include?(mod)` hangs up, because it is overwritten by `Enumerable#include?(obj)` and tries to search `mod` linearly from infinite sequence of prime numbers.


**Reproducible script:**

~~~
$ ruby -e 'require "prime"; puts Prime.include?(Enumerable)'
~~~

* Expected: returns `true`
* Actual: hangs up


I found this bug by the following code (hangs up if prime is required)

~~~ruby
enumerables = []
ObjectSpace.each_object(Class){|klass|
  if klass.include?(Enumerable) then
    enumerables.push klass
  end
}
~~~

---Files--------------------------------
prime-include.diff (1.21 KB)


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