Issue #17055 has been updated by byroot (Jean Boussier).


I have no particular opinion on the instance variable part, except that it makes me think of [this request of reporting on instance variable typos](https://discuss.rubyonrails.org/t/typos-in-instance-variable-names-can-give-confusing-error-messages/74511). It could be interesting to design the API in such a way that a DidYouMean integration would be possible.

With the currently proposed API it would look like?

```ruby
def expected_uninitialized_instance_variable?(iv)
  DidYouMean.something(instance_variables, iv)
  false
end
```

Which doesn't seem too bad.

----------------------------------------
Feature #17055: Allow suppressing uninitialized instance variable and method redefined verbose mode warnings
https://bugs.ruby-lang.org/issues/17055#change-86795

* Author: jeremyevans0 (Jeremy Evans)
* Status: Open
* Priority: Normal
----------------------------------------
These two verbose mode warnings are both fairly common and have good reasons why you would not want to warn about them in specific cases.  Not initializing instance variables to nil can be much better for performance, and redefining methods without removing the method first is the only safe approach in multi-threaded code.

There are reasons that you may want to issue verbose warnings by default in these cases.  For uninitialized instance variables, it helps catch typos. For method redefinition, it could alert you that a method already exists when you didn't expect it to, such as when a file is loaded multiple times when it should only be loaded once.

I propose we keep the default behavior the same, but offer the ability to opt-out of these warnings by defining methods.  For uninitialized instance variables in verbose mode, I propose we call `expected_uninitialized_instance_variable?(iv)` on the object.  If this method doesn't exist or returns false/nil, we issue the warning.  If the method exists and returns true, we suppress the warning.  Similarly, for redefined methods, we call `expected_redefined_method?(method_name)` on the class or module.  If the method doesn't exist or returns false/nil, we issue the warning.  If the method exists and returns true, we suppress the warning.

This approach allows high performance code (uninitialized instance variables) and safe code (redefining methods without removing) to work without verbose mode warnings.

I have implemented this support in a pull request: https://github.com/ruby/ruby/pull/3371



-- 
https://bugs.ruby-lang.org/

Unsubscribe: <mailto:ruby-core-request / ruby-lang.org?subject=unsubscribe>
<http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>