From: "zverok (Victor Shepelev) via ruby-core" <ruby-core@...>
Date: 2024-12-23T06:19:02+00:00
Subject: [ruby-core:120374] [Ruby master Bug#20965] `it` vs `binding.local_variables`

Issue #20965 has been updated by zverok (Victor Shepelev).


Interestingly, numbered block parameters do this:

```ruby
"foo".tap do
  _1
  "bar".tap do
    p binding.local_variables #=> [_1]
    eval("_1") #  undefined local variable or method '_1' for main:Object (NameError)
  end
end
```

I am not saying this is good behavior, though. The things I am concerned about (after the release, of course):
1. Whatever the behavior is, it is deliberate and documented;
2. Whatever the behavior is, it is internally consistent (e.g., in #20955 the thing that surprised me was an inconsistency between proc and lambda);
3. Whatever the behavior is, I���d expect it to be as consistent as possible between `it` and numbered anonymous parameters.

(About the latter one: `it`s behavior, after the change is reverted, actually seems more internally consistent at least between `local_variables` and `eval`, so maybe numbered parameters should follow?)

----------------------------------------
Bug #20965: `it` vs `binding.local_variables`
https://bugs.ruby-lang.org/issues/20965#change-111151

* Author: zverok (Victor Shepelev)
* Status: Open
* ruby -v: ruby 3.4.0dev (2024-12-15T13:36:38Z master 366fd9642f) +PRISM [x86_64-linux]
* Backport: 3.1: DONTNEED, 3.2: DONTNEED, 3.3: DONTNEED
----------------------------------------
`it` is not available in the list of `binding.local_varaibles`, **unlike** numbered parameters:

```ruby
p(proc { binding.local_variables }.call)  # []
p(proc { |x| binding.local_variables }.call)  # [:x]
p(proc { _1; binding.local_variables }.call)  # [:_1]
p(proc { vars = binding.local_variables; _1; vars }.call)  # [:_1, :vars]
p(proc { it; binding.local_variables }.call)  # []
```

I wonder if it is deliberate or accidental.



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