[ruby-core:106514] [Ruby master Bug#18385] Refinement#import_methods(Enumerable) doesn't work

Issue #18385 has been updated by zverok (Victor Shepelev).


Eregon (Benoit Daloze) wrote in #note-5:
> zverok (Victor Shepelev) wrote in #note-2:
> > I didn't realize that `import_methods` is a make-believe feature, not really integrated with the interpreter/object model. 
> 
> Not sure what you mean by that, in my POV it is integrated and it has the effect to "copy" methods from a module to another module or to a refinement, so that refinements can apply as if they were defined there lexically.
> 
> C extension-defined methods never supported refinements and likely never will (there is no lexical context for a call there).

Well... We can look from many different angles at the problem. 

From one side, I can understand the technical reasons how you explain them. 

On another side, I still "intuitively" expect refinements to be a hygienic replacement for `core_ext.rb`, and every time this expectation fails, I am a bit frustrated. I mean, I might do that, right?.. (Save for the sanity of this approach discussion, but imagine I hack a few scripts for quick binary data investigation and decided in _those_ scripts it would be the most convenient):

```ruby
class String
  alias each each_byte
  include Enumerable
end

[1, 2, 3].chain('123').zip('abcdef')
# => [[1, 97], [2, 98], [3, 99], [49, 100], [50, 101], [51, 102]]
```
...but I can't for the love of all gods achieve the same with refinements—which would be **the very first guess** if you do something so violent you need in **exactly one algorithm**.

That's why I call `import_methods` a "make-believe" feature: unlike `include`/`extend` (which didn't work in refinements) it makes the border between methods defined in Ruby and methods defined in C visible, and thus look like something loosely glued on top of the object model.

It can be "technically explained", but it doesn't become "natural" after the explanation. 

But honestly, I feel like the whole mental model of refinements is doomed from the start, the limitation of the "additional" functionality to text file borders is unusable in a dynamic language.

(As an aside note, it is funny how "extension methods" became in fashion in all the languages that criticized Ruby for being "too unreliable" for being able to extend core classes—and at the same time, in the Ruby community, it became a taboo.)

----------------------------------------
Bug #18385: Refinement#import_methods(Enumerable) doesn't work
https://bugs.ruby-lang.org/issues/18385#change-95175

* Author: zverok (Victor Shepelev)
* Status: Closed
* Priority: Normal
* Assignee: shugo (Shugo Maeda)
* Backport: 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN
----------------------------------------
Very simple to reproduce:
```ruby
module M
  refine String do
    import_methods Enumerable
  end
end
```
Leads to: `import_methods': Can't import method: Enumerable#drop (ArgumentError)`
Which, grepping through code, seems to be raised [here](https://github.com/ruby/ruby/blob/master/eval.c#L1529) but I am not versed enough in Ruby internals to debug further.

An attempt to `import_methods Comparable` leads to the same problem, BTW: `Can't import method: Comparable#between?`

Am I missing something crucial about `import_method` behavior?



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