From: eregontp@...
Date: 2020-08-22T09:56:41+00:00
Subject: [ruby-core:99671] [Ruby master Bug#16853] calling bla(hash, **kw) with a string-based hash passes the strings into **kw (worked < 2.7)

Issue #16853 has been updated by Eregon (Benoit Daloze).


sylvain.joyeux (Sylvain Joyeux) wrote in #note-9:
> Keyword splat would not allow anything but symbols as keys pre-2.7.

Indeed, so what happens is the Hash is magically split in two if it has non-Symbol keys (or `raise`s with `**`):

```
Ruby 2.6.6

$ ruby -e 'def m(*args, **kwargs); [args, kwargs]; end; h = { k: 2, "c" => 20 }; p m(h)'  
[[{"c"=>20}], {:k=>2}]

$ ruby -e 'def m(*args, **kwargs); [args, kwargs]; end; h = { k: 2, "c" => 20 }; p m(**h)'
Traceback (most recent call last):
-e:1:in `<main>': hash key "c" is not a Symbol (TypeError)
```

> When it comes to optimization, though, I would assume that the keywords are all symbols would open a lot more doors.

No, it just added more checks as every call with keyword arguments would need to check all keys are Symbols.

----------------------------------------
Bug #16853: calling bla(hash, **kw) with a string-based hash passes the strings into **kw (worked < 2.7)
https://bugs.ruby-lang.org/issues/16853#change-87158

* Author: sylvain.joyeux (Sylvain Joyeux)
* Status: Rejected
* Priority: Normal
* ruby -v: 2.7.1p83
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN
----------------------------------------
The following code

~~~
def bla(hash = {}, **kw)
    puts "H: #{hash}"
    puts "K: #{kw}"
end

bla "some" => "string"
~~~

**silently** outputs the following (no warnings about deprecation of keyword parameters-from-hash)

~~~
H: {}
K: {"some"=>"string"}
~~~

While 2.6.5 (and versions before it) gave

~~~
H: {"some"=>"string"}
K: {}
~~~

I would expect "the warning" that started appearing in 2.7, and **definitely** not having strings in a keyword argument hash.



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