[ruby-core:119577] [Ruby master Bug#20808] Cannot override Data#inspect

21 Oct 2024

      Issue #20808 has been updated by byroot (Jean Boussier).

The `pp` implementation for  `Struct` and `Data` both assume all member readers are public:

```ruby
class Struct # :nodoc:
  def pretty_print(q) # :nodoc:
    q.group(1, sprintf("#<struct %s", PP.mcall(self, Kernel, :class).name), '>') {
      q.seplist(PP.mcall(self, Struct, :members), lambda { q.text "," }) {|member|
        q.breakable
        q.text member.to_s
        q.text '='
        q.group(1) {
          q.breakable ''
          q.pp self[member]
        }
      }
    }
  end

  def pretty_print_cycle(q) # :nodoc:
    q.text sprintf("#<struct %s:...>", PP.mcall(self, Kernel, :class).name)
  end
end

class Data # :nodoc:
  def pretty_print(q) # :nodoc:
    q.group(1, sprintf("#<data %s", PP.mcall(self, Kernel, :class).name), '>') {
      q.seplist(PP.mcall(self, Data, :members), lambda { q.text "," }) {|member|
        q.breakable
        q.text member.to_s
        q.text '='
        q.group(1) {
          q.breakable ''
          q.pp public_send(member)
        }
      }
    }
  end

  def pretty_print_cycle(q) # :nodoc:
    q.text sprintf("#<data %s:...>", PP.mcall(self, Kernel, :class).name)
  end
end if "3.2" <= RUBY_VERSION
```

----------------------------------------
Bug #20808: Cannot override Data#inspect
https://bugs.ruby-lang.org/issues/20808#change-110196

* Author: maicolben (Maicol Bentancor)
* Status: Open
* ruby -v: 3.3.5
* Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN
----------------------------------------
Given the next code:
```
Dog = Data.define(:name) do
  def inspect
    "Hello!"
  end

  private
  attr_reader :name
end

Dog.new(name: "Fido")
```

It throws an error:
- An error occurred when inspecting the object: #<NoMethodError: private method `name' called for an instance of Dog> 

And isn't using my `inspect` function

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