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Bug #5236

closed

Including a module in a superclass after it has been included in a subclass leads to infinite recursion if the module uses `super`

Added by myronmarston (Myron Marston) over 10 years ago. Updated over 9 years ago.

Status:
Closed
Priority:
Normal
Target version:
ruby -v:
1.9.x
Backport:
[ruby-core:39132]

Description

Under these particular circumstances, you get infinite recursion and a system stack error on 1.9 but not 1.8:

  • Create a module that has a method that uses super
  • Include that module in a class after it has already been included in one of its subclasses
  • Instantiate an object of said subclass and call the method

On 1.8, the super works as expected. On 1.9 you get a SystemStackError. Here's example code that demonstrates the issue:

example.rb

module MyModule
def some_method; super; end
end

class MyBaseClass; end

class MySubClass < MyBaseClass;
include MyModule
end

To trigger this bug, we must include the module in the base class after

the module has already been included in the subclass. If we move this line

above the subclass declaration, this bug will not occur.

MyBaseClass.send(:include, MyModule)

MySubClass.new.some_method

The output

➜ ruby --version
ruby 1.8.7 (2011-02-18 patchlevel 334) [i686-darwin10.6.0]
➜ ruby example.rb
example.rb:2:in some_method': super: no superclass method some_method' for #MySubClass:0x1001bc2d0 (NoMethodError)
from example.rb:2:in `some_method'
from example.rb:13

➜ ruby --version
ruby 1.9.2p180 (2011-02-18 revision 30909) [x86_64-darwin10.6.0]
➜ ruby example.rb
example.rb:2: stack level too deep (SystemStackError)

I've tried it on 1.9.3.preview-1 and I get the SystemStackError there, too. I would expect 1.9 to act like 1.8 here, and not infinitely recurse on itself.


Related issues 2 (0 open2 closed)

Related to Ruby master - Bug #3351: stack overflow on superClosedko1 (Koichi Sasada)Actions
Related to Ruby master - Feature #1586: Including a module already present in ancestors should not be ignoredRejectedmatz (Yukihiro Matsumoto)Actions
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