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 12 years ago. Updated about 11 years ago.

Status:

Closed

Assignee:

nobu (Nobuyoshi Nakada)

Target version:

2.0.0

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 open — 2 closed)