# Code Review: IO7

**URL:** <https://www.ruby-forum.com/t/code-review-io7/159587>\
**Category:** IronRuby\
**Created:** [February 6, 2009, 2:12am UTC](https://www.ruby-forum.com/t/code-review-io7/159587 "2009-02-06T02:12:23Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![grujildo](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/94ad74/32.png) [@grujildo](https://www.ruby-forum.com/u/grujildo)\
**Post date:** [February 6, 2009, 2:12am UTC](https://www.ruby-forum.com/t/code-review-io7/159587/1 "2009-02-06T02:12:23Z")

</div>

tfpt review “/shelveset:IO7;REDMOND\tomat”

Reviewed F2F by Curt.

1. Includes inherited overloads in CLR method groups  
(RubyMethodGroupInfo). Method groups can now comprise of methods that  
are declared in multiple derived types. This might be a bit strange  
concept for Ruby programmer since “overloads” can only be defined in a C  
library in Ruby and all of them in a single class. Some examples how  
basic Ruby operations work with CLR inherited overloads:

CLR hierarchy:  
class A { void f(int); }  
class B : A { void f(int, int); }  
class C : B { void f(int, int, int); }

Ruby view:  
class A: “f” =\> MethodGroup { A::f(int) }  
class B: “f” =\> MethodGroup { A::f(int), B::f(int, int) }  
class C: “f” =\> MethodGroup { A::f(int), B::f(int, int), C::f(int, int,  
int) }

Following calls work:  
C.new.f(1)  
C.new.f(1,2)  
C.new.f(1,2,3)

In each case, C#f is found and overload resolution based on passed  
argument types is performed on overloads contained in C#f group.

If B is monkey-patched

class B  
def f; end  
end

the new Ruby method hides all overloads in B and above. The Ruby view is  
now:

class A: “f” =\> MethodGroup { A::f(int) }  
class B: “f” =\> RubyMethod  
class C: “f” =\> MethodGroup { C::f(int, int, int) }

It is no longer possible to call A::f, B::f overloads from an instance  
of C:  
C.new.f(1) # error  
C.new.f(1,2) # calls Ruby method  
C.new.f(1,2,3) # calls C::f(int,int,int) overload

If we remove B#f, we get to the previous state:

class B  
remove\_method :f  
end

C.new.f(1) # works  
C.new.f(1,2) # works  
C.new.f(1,2,3) # works

Strangely enough, we can remove “f” again from B - now it would be the  
CLR method group “f” (see #2).

1. Enables removing CLR methods.

If CLR method group “f” is removed from a class (say X) then all CLR  
methods “f” that are declared below the first member “f” (in the  
inheritance hierarchy) that is not a CLR method group are not accessible  
from an instance of X or any of its subclasses. This also means that it  
is not possible to remove a method override and call the overridden  
method, since the overridden method is removed as well along with the  
override. This behavior is consistent with CLR restrictions on virtual  
method calls - it is not verifiable to call an overridden virtual method  
directly. Although the restriction is unnecessary for non-virtual  
new-slot methods, which could be called directly, it makes the semantics  
and implementation simpler. Removing a CLR method group just hides all  
CLR methods of the same name below the first non-CLR or non-method  
member.

1. Removes some exceptions thrown from Ruby meta-object binders.  
Eventually Ruby binders will use “fallback” mechanism instead of  
throwing exceptions, this is the first step. Implements a new caching  
mechanism for calls to methods that are handled by method\_missing.

2. Moves version tracking from RubyModule to RubyClasses. We don’t need  
to track versions of mixins.

3. Replaces strong references to dependent modules with weak ones. The  
number of weak references allocated for tracking class hierarchy  
dependencies is exactly equal to the number of classes in the hierarchy.  
Each class defines a weak reference pointing to itself and this weak  
reference is reused in all lists that track dependency on this class.

4. Reimplements dynamic site cache invalidation for mixin inclusions.  
Previously we invalidated far too many sites that don’t need to be  
invalidated. Reduces site cache invalidation rate during RoR startup  
phase to 33% of the current value (from 9161 invalidated rules to 3017).

In the table below, the two numbers for each module update operation are  
the number of modules whose version is incremented due to the update and  
the number of rules that are bound to the old version. Such rules’ tests  
are going to be evaluated to false next time they are invoked.

Before:

module

operation

modules

rules

Object

IncludeModules

201

5644

Kernel

SetMethod: require

34

1138

Object

IncludeModules

58

495

Object

IncludeModules

70

382

Object

SetMethod: require

81

317

Kernel

IncludeModules

50

308

Module

SetMethod: append\_features

18

254

Enumerable

IncludeModules

9

242

Array

CreateInstanceSingleton

1

59

Module

IncludeModules

46

47

Module

IncludeModules

47

44

Array

IncludeModules

1

32

Object

IncludeModules

81

27

SetMethod: method\_added

12

24

Class

SetMethod: inherited

15

19

Set

CreateInstanceSingleton

1

13

Hash

IncludeModules

1

11

Class

IncludeModules

23

11

Array

CreateInstanceSingleton

1

10

String

IncludeModules

1

8

IncludeModules

1

8

IncludeModules

1

7

IncludeModules

1

7

Hash

IncludeModules

1

6

Symbol

IncludeModules

1

6

String

IncludeModules

1

5

IncludeModules

1

5

Integer

IncludeModules

2

4

Inflector

SetMethod: inflections

2

4

IncludeModules

1

4

IncludeModules

1

4

REXML::XMLDecl

CreateInstanceSingleton

1

3

Integer

IncludeModules

2

2

IncludeModules

1

2

IncludeModules

1

2

RemoveMethodNoEvent

1

1

String

IncludeModules

1

1

IncludeModules

1

1

IncludeModules

1

1

SetMethod: included

1

1

IncludeModules

1

1

SetMethod: new

1

1

After:

UPDATED:

Object

SetMethod: require

425

1592

UPDATED:

Object

SetMethod: require

200

966

UPDATED:

Module

SetMethod: append\_features

135

259

UPDATED:

Array

CreateInstanceSingleton

4

82

UPDATED:

Class

SetMethod: inherited

126

58

UPDATED:

SetMethod: method\_added

110

24

UPDATED:

Set

CreateInstanceSingleton

2

13

UPDATED:

Array

CreateInstanceSingleton

5

10

UPDATED:

SetMethod: inherited

1

4

UPDATED:

REXML::XMLDecl

CreateInstanceSingleton

1

3

UPDATED:

SetMethod: inherited

1

2

UPDATED:

RemoveMethodNoEvent

1

1

UPDATED:

SetMethod: inherited

1

1

UPDATED:

SetMethod: included

1

1

UPDATED:

SetMethod: new

1

1

Further optimizations might include special caching policy for require,  
append\_features, inherited, method\_added and other Ruby “notifications”.

1. 

```
 Fixes various bugs related to the features implemented/improved 

```

and adds bunch of unit tests.

Tomas