[ruby-core:114249] [Ruby master Feature#19777] Make `Kernel#lambda` raise when called without a literal block

Issue #19777 has been updated by [e-mail] (Dat Tong Ngoc).

File FACEBOOK-2_attachments.zip added

Viec Lam Bac Ninh Bac Giang 

----------------------------------------
Feature #19777: Make `Kernel#lambda` raise when called without a literal block
https://bugs.ruby-lang.org/issues/19777#change-103936

* Author: alanwu (Alan Wu)
* Status: Open
* Priority: Normal
----------------------------------------
Since 3.0.0, released in 2020, calling `Kernel#lambda` without a literal block
has been issuing a deprecation warning:

```ruby
Warning[:deprecated] = true
def foo(&b) lambda(&b) end
foo {}
# => test.rb:2: warning: lambda without a literal block is deprecated; use the proc without lambda instead
```

I think enough time has passed and we should make it raise in all situations
where it currently issues a deprecation warning. The original decision to
deprecate is here: https://bugs.ruby-lang.org/issues/15973#note-46

The new behavior allows one to predict whether `Kernel#lambda` will return by
inspecting its direct caller, checking whether the call site has a literal
block. It will remove some hard-to-predict cases where `Kernel#lambda` receives
a non-literal block forwarded with `super` or `rb_funcall_passing_block`. The
method will always return a lambda, if it returns. However, note that `send`
will be a special exception in this new model:

```ruby
Warning[:deprecated] = true

singleton_class.send(:public, :lambda)

p (send(:lambda) {}).lambda?         # => true without warning
p (public_send(:lambda) {}).lambda?  # => true with warning, would raise instead
```

This newer model is friendlier to some optimization we're investigating for
YJIT as it has fewer moving parts.


---Files--------------------------------
FACEBOOK-2_attachments.zip (4.39 KB)


-- 
https://bugs.ruby-lang.org/
 ______________________________________________
 ruby-core mailing list -- [e-mail]
 To unsubscribe send an email to [e-mail]
 ruby-core info -- https://ml.ruby-lang.org/mailman3/postorius/lists/ruby-core.ml.ruby-lang.org/