[ruby-core:122373] [Ruby Bug#21392] Data classes do not allow overriding #inspect

2 Jun 2025

      Issue #21392 has been updated by mame (Yusuke Endoh).

I cannot reproduce the issue neither.

```
$ cat t.rb
module Color
  CIELAB = Data.define(:l, :a, :b) do
    def inspect
      "CIELAB [%.4f%% %.4f %.4f]" % [l, a, b]
    end
  end
end

p Color::CIELAB[1,2,3]

$ ruby -v t.rb
ruby 3.4.2 (2025-02-15 revision d2930f8e7a) +PRISM [x86_64-linux]
CIELAB [1.0000% 2.0000 3.0000]
```

----------------------------------------
Bug #21392: Data classes do not allow overriding #inspect
https://bugs.ruby-lang.org/issues/21392#change-113517

* Author: austin (Austin Ziegler)
* Status: Feedback
* ruby -v: 3.4.4
* Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN
----------------------------------------
I'm preparing a new version of Color and I have decided to make all of the colour classes Data classes. However, it does not appear that `#inspect` can be overridden:

```ruby
module Color
  CIELAB = Data.define(:l, :a, :b) do
    def inspect
      "CIELAB [%.4f%% %.4f %.4f]" % [l, a, b]
    end
  end
end

p Color::CIELAB[1,2,3]
# Expected => CIELAB[1.000% 2.000 3.000]
# Actual #<data Color::CIELAB l=10, a=-125.0, b=20.5>
```

This feels like it should be permitted.

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