From: "nobu (Nobuyoshi Nakada)" <noreply@...>
Date: 2021-11-06T05:00:40+00:00
Subject: [ruby-core:105955] [Ruby master Bug#18289] Enumerable#to_a should delegate keyword arguments to #each

Issue #18289 has been updated by nobu (Nobuyoshi Nakada).


jeremyevans0 (Jeremy Evans) wrote in #note-5:
> nobu (Nobuyoshi Nakada) wrote in #note-4:
> > Recently I've encountered similar issue with `grep(regexp, chomp: true)`.
> 
> What's the issue with `grep`?  If it is a keyword issue, we can probably fix it.

Same as this issue.

> > And `IO#each` has the separator and limit arguments, I wonder how to pass them.
> 
> `IO#each` doesn't use keywords, so `to_a` should pass the arguments even before commit:e83c02a768af61cd0890a75e90bcae1119d8bd93:

As the number of arguments of `#grep` is fixed, it won't be a problem in this case.
And `#to_a` has delegated all arguments to `#each`, so it didn't have problems.
But what about methods which have optional parameters, e.g. `Enumerable#count`?
Although it's possible to make the first argument mandatory when passing arguments for `#each`, it doesn't feel very nice.

----------------------------------------
Bug #18289: Enumerable#to_a should delegate keyword arguments to #each
https://bugs.ruby-lang.org/issues/18289#change-94502

* Author: Ethan (Ethan -)
* Status: Closed
* Priority: Normal
* ruby -v: ruby 3.0.2p107 (2021-07-07 revision 0db68f0233) [x86_64-linux]
* Backport: 2.6: DONTNEED, 2.7: REQUIRED, 3.0: REQUIRED
----------------------------------------
`Enumerable#to_a` has always delegated its arguments to `#each`, but it does not handle keyword arguments. This seems like an oversight.

My project uses keyword arguments to an #each method, and this has broken Enumerable#to_a as of ruby 3 (and generates a warning on ruby 2.7).


```ruby
class Foo
  include Enumerable

  def each(opt: )
    yield 'foo'
  end
end

pp Foo.new.to_a(opt: 4)
```

ruby 2.4

```
["foo"]
```

ruby 2.7

```
to_a_kw_arg_delegation.rb:8: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
to_a_kw_arg_delegation.rb:3: warning: The called method `each' is defined here
["foo"]
```

ruby 3

```
to_a_kw_arg_delegation.rb:3:in `each': wrong number of arguments (given 1, expected 0; required keyword: opt) (ArgumentError)
  from to_a_kw_arg_delegation.rb:8:in `to_a'
  from to_a_kw_arg_delegation.rb:8:in `<main>'
```


---Files--------------------------------
to_a_kw_arg_delegation.rb (101 Bytes)


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