[ruby-core:98288] [Ruby master Feature#16832] Use #name rather than #inspect to build "uninitialized constant" error messages

Issue #16832 has been updated by Dan0042 (Daniel DeLorme).


+1 for using #name and falling back to #inspect

Rails is correct in extending inspect to return more useful human-readable information, and a NameError should tell you about the problem name (including namespace), not about extra information regarding the module/class to which the namespace resolves. I feel that depending on #inspect to return the name here is a hack.

Ideally the NameError would contain the fully-qualified constant name actually used in the code:

```
class A; end
B = A
B::X #=> NameError (uninitialized constant A::X)
     # ideally would say constant B::X
```

but that's getting a bit out of scope for this ticket. #name is the next-best choice.


----------------------------------------
Feature #16832: Use #name rather than #inspect to build "uninitialized constant" error messages
https://bugs.ruby-lang.org/issues/16832#change-85528

* Author: byroot (Jean Boussier)
* Status: Open
* Priority: Normal
----------------------------------------
While debugging a bug in Rails (https://github.com/rails/rails/pull/37632#issuecomment-623387954) I noticed `NameError` calls `inspect` on the `const_get` receiver to build its error message.

The problem is that some libraries such as Active Record have been redefining `inspect` for years to provide human readable information, e.g.: 

```
>> Shipit::Stack.inspect
=> "Shipit::Stack (call 'Shipit::Stack.connection' to establish a connection)"
>> Shipit::Stack.connection; nil
>> Shipit::Stack.inspect
=> "Shipit::Stack(id: integer, environment: string, ...)"
```

Which makes for fairly unhelpful error messages:

```
>> Shipit::Stack.const_get(:Foo)
Traceback (most recent call last):
        2: from (irb):4
        1: from (irb):4:in `const_get'
NameError (uninitialized constant #<Class:0x00007fc8cadf2dd0>::Foo)
```

So perhaps it's Active Record that is at fault here, but from my understanding since the goal is to display the constant path that was requested, `name` is much more likely to return a relevant constant name.

Proposed patch: https://github.com/ruby/ruby/pull/3080



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