[ruby-core:109848] [Ruby master Bug#18998] Kernel#Integer does not convert SimpleDelegator expectly

[ruby-core:109848] [Ruby master Bug#18998] Kernel#Integer does not convert SimpleDelegator expectly

[taichi730 (Taichi Ishitani)]

Issue #18998 has been reported by taichi730 (Taichi Ishitani).

----------------------------------------
Bug #18998: Kernel#Integer does not convert SimpleDelegator expectly
https://bugs.ruby-lang.org/issues/18998

* Author: taichi730 (Taichi Ishitani)
* Status: Open
* Priority: Normal
* ruby -v: ruby 3.1.2p20 (2022-04-12 revision 4491bb740a) [x86_64-linux]
* Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN
----------------------------------------
Kernel#Integer method doens not convert a SimpleDelegator object of which value is a String.
This is an sample code.

``` ruby
require 'delegate'
p Integer(SimpleDelegator.new('0x10'))
```

I expect Kernel#Integer to convert the input value as a String and the expected returned value is `16`.
Hoever the actual returned value is `0` so it's seemed that `#to_i` method is just called.

```
taichi@LAPTOP-TVTKLNFD:temp
$ cat test.rb
require 'delegate'
p Integer(SimpleDelegator.new('0x10'))

taichi@LAPTOP-TVTKLNFD:temp
$ ruby test.rb
0
```

Which is the correct behavior?




-- 
https://bugs.ruby-lang.org/

[ruby-core:109855] [Ruby master Bug#18998] Kernel#Integer does not convert SimpleDelegator object expectly

[byroot (Jean Boussier)]

Issue #18998 has been updated by byroot (Jean Boussier).


So this behavior isn't documented, so it's hard to say wether it's correct:

> Integer(arg, base=0, exception: true) → integer or nil
Converts arg to an Integer. Numeric types are converted directly (with floating point numbers being truncated). base (0, or between 2 and 36) is a base for integer string representation. If arg is a String, when base is omitted or equals zero, radix indicators (0, 0b, and 0x) are honored. In any case, strings should consist only of one or more digits, except for that a sign, one underscore between two digits, and leading/trailing spaces are optional. This behavior is different from that of String#to_i. Non string values will be converted by first trying to_int, then to_i.

> Passing nil raises a TypeError, while passing a String that does not conform with numeric representation raises an ArgumentError. This behavior can be altered by passing exception: false, in this case a not convertible value will return nil.

However the intent of the implementation is fairly clear:

```
static VALUE
rb_convert_to_integer(VALUE val, int base, int raise_exception)
{
    VALUE tmp;
    // snip
    if (RB_FLOAT_TYPE_P(val)) {
        double f = RFLOAT_VALUE(val);
        if (!raise_exception && !isfinite(f)) return Qnil;
        if (FIXABLE(f)) return LONG2FIX((long)f);
        return rb_dbl2big(f);
    }
    else if (RB_INTEGER_TYPE_P(val)) {
        return val;
    }
    else if (RB_TYPE_P(val, T_STRING)) {
        return rb_str_convert_to_inum(val, base, TRUE, raise_exception);
    }
    else if (NIL_P(val)) {
        if (!raise_exception) return Qnil;
        rb_raise(rb_eTypeError, "can't convert nil into Integer");
    }

    tmp = rb_protect(rb_check_to_int, val, NULL);
    if (RB_INTEGER_TYPE_P(tmp)) return tmp;
    rb_set_errinfo(Qnil);

    if (!raise_exception) {
        VALUE result = rb_protect(rb_check_to_i, val, NULL);
        rb_set_errinfo(Qnil);
        return result;
    }

    return rb_to_integer(val, "to_i", idTo_i);
}
```

If passed an object that is neither a direct string nor a native numeric, `Integer` first tries to invoke `to_int`, then fallback to invoke `to_i`.

I suppose a case could be made to first try to call `to_str`.

----------------------------------------
Bug #18998: Kernel#Integer does not convert SimpleDelegator object expectly
https://bugs.ruby-lang.org/issues/18998#change-99092

* Author: taichi730 (Taichi Ishitani)
* Status: Open
* Priority: Normal
* ruby -v: ruby 3.1.2p20 (2022-04-12 revision 4491bb740a) [x86_64-linux]
* Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN
----------------------------------------
Kernel#Integer method doens not convert a SimpleDelegator object of which value is a String.
This is an sample code.

``` ruby
require 'delegate'
p Integer(SimpleDelegator.new('0x10'))
```

I expect Kernel#Integer to convert the input value as a String and the expected returned value is `16`.
Hoever the actual returned value is `0` so it's seemed that `#to_i` method is just called.

```
taichi@LAPTOP-TVTKLNFD:temp
$ cat test.rb
require 'delegate'
p Integer(SimpleDelegator.new('0x10'))

taichi@LAPTOP-TVTKLNFD:temp
$ ruby test.rb
0
```

Which is the correct behavior?




-- 
https://bugs.ruby-lang.org/

[ruby-core:109862] [Ruby master Bug#18998] Kernel#Integer does not convert SimpleDelegator object expectly

[taichi730 (Taichi Ishitani)]

Issue #18998 has been updated by taichi730 (Taichi Ishitani).


Thank you for your reply.
I understood that there is no documented specification and the current implementation.

How should Integer method behave for this case?
My thought is that Integer method should convert a Delegator object like when a String is given.
Because of this, I override Integer method like below in my project.

```ruby
module Kernel
  alias_method :__orignal_Integer, :Integer

  def Integer(arg, base = 0, exception: true)
    arg = arg.__getobj__ if arg.is_a?(::Delegator)
    __orignal_Integer(arg, base, exception: exception)
  end
end
```

----------------------------------------
Bug #18998: Kernel#Integer does not convert SimpleDelegator object expectly
https://bugs.ruby-lang.org/issues/18998#change-99102

* Author: taichi730 (Taichi Ishitani)
* Status: Open
* Priority: Normal
* ruby -v: ruby 3.1.2p20 (2022-04-12 revision 4491bb740a) [x86_64-linux]
* Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN
----------------------------------------
Kernel#Integer method doens not convert a SimpleDelegator object of which value is a String.
This is an sample code.

``` ruby
require 'delegate'
p Integer(SimpleDelegator.new('0x10'))
```

I expect Kernel#Integer to convert the input value as a String and the expected returned value is `16`.
Hoever the actual returned value is `0` so it's seemed that `#to_i` method is just called.

```
taichi@LAPTOP-TVTKLNFD:temp
$ cat test.rb
require 'delegate'
p Integer(SimpleDelegator.new('0x10'))

taichi@LAPTOP-TVTKLNFD:temp
$ ruby test.rb
0
```

Which is the correct behavior?




-- 
https://bugs.ruby-lang.org/

[ruby-core:109865] [Ruby master Bug#18998] Kernel#Integer does not convert SimpleDelegator object expectly

[byroot (Jean Boussier)]

Issue #18998 has been updated by byroot (Jean Boussier).


> My thought is that Integer method should convert a Delegator object like when a String is given.

I don't think it would be advisable for `Kernel#Integer` to know about `Delegator`. `Delegator` is just a class from the stdlib, you could implement the same yourself and that wouldn't solve your problem.

I think based on the spec lined up above, it would be best if you defined `#to_int` on your delegator. But I don't know your full use case, so not sure if it's relevant.

Either way I don't think there is really a bug here, aside from maybe the method needed more documentation.

A change of behavior would fall under a feature request, and a proper spec would need to be drafted. The only possible change I could see would be to try to call `to_str` between `to_int` and `to_i`, but that could be a breaking change, so a hard sell.

----------------------------------------
Bug #18998: Kernel#Integer does not convert SimpleDelegator object expectly
https://bugs.ruby-lang.org/issues/18998#change-99105

* Author: taichi730 (Taichi Ishitani)
* Status: Open
* Priority: Normal
* ruby -v: ruby 3.1.2p20 (2022-04-12 revision 4491bb740a) [x86_64-linux]
* Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN
----------------------------------------
Kernel#Integer method doens not convert a SimpleDelegator object of which value is a String.
This is an sample code.

``` ruby
require 'delegate'
p Integer(SimpleDelegator.new('0x10'))
```

I expect Kernel#Integer to convert the input value as a String and the expected returned value is `16`.
Hoever the actual returned value is `0` so it's seemed that `#to_i` method is just called.

```
taichi@LAPTOP-TVTKLNFD:temp
$ cat test.rb
require 'delegate'
p Integer(SimpleDelegator.new('0x10'))

taichi@LAPTOP-TVTKLNFD:temp
$ ruby test.rb
0
```

Which is the correct behavior?




-- 
https://bugs.ruby-lang.org/

[ruby-core:109871] [Ruby master Bug#18998] Kernel#Integer does not convert SimpleDelegator object expectly

[taichi730 (Taichi Ishitani)]

Issue #18998 has been updated by taichi730 (Taichi Ishitani).


> it would be best if you defined #to_int on your delegator

I've tried this approach but it was failed because `base` and `exception` arguments cannot be passed to `#to_i` method on my delegator.
Therefore, I've overridden `Kernel#Integer` method.



----------------------------------------
Bug #18998: Kernel#Integer does not convert SimpleDelegator object expectly
https://bugs.ruby-lang.org/issues/18998#change-99111

* Author: taichi730 (Taichi Ishitani)
* Status: Open
* Priority: Normal
* ruby -v: ruby 3.1.2p20 (2022-04-12 revision 4491bb740a) [x86_64-linux]
* Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN
----------------------------------------
Kernel#Integer method doens not convert a SimpleDelegator object of which value is a String.
This is an sample code.

``` ruby
require 'delegate'
p Integer(SimpleDelegator.new('0x10'))
```

I expect Kernel#Integer to convert the input value as a String and the expected returned value is `16`.
Hoever the actual returned value is `0` so it's seemed that `#to_i` method is just called.

```
taichi@LAPTOP-TVTKLNFD:temp
$ cat test.rb
require 'delegate'
p Integer(SimpleDelegator.new('0x10'))

taichi@LAPTOP-TVTKLNFD:temp
$ ruby test.rb
0
```

Which is the correct behavior?




-- 
https://bugs.ruby-lang.org/