You should not inherit from Struct.new

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Metadata

ID: ruby-best-practices/no-extend-struct-new

Language: Ruby

Severity: Notice

Category: Best Practices

Description

The rule, “You should not inherit from Struct.new”, is important because it can lead to unexpected behavior and bugs in your code. Struct.new creates a new Class, and if you inherit from it, you’re creating a subclass of a dynamically generated Class. This can lead to confusing code and can make debugging difficult.

Instead of inheriting from Struct.new, you should assign the result of Struct.new to a constant. This will create a new Class with the provided attributes, and you can add methods to it just like any other Class. This approach is clearer and less prone to errors.

To avoid this, use Struct.new to create a new class and assign it to a constant. For example, Foo = Struct.new(:foo, :bar) creates a new Class with two attributes, foo and bar, and assigns it to the constant Foo. This is a far safer and more predictable way to use Struct.new in your code.

Non-Compliant Code Examples

class Foo < Struct.new(:foo, :bar)
end

class Foo < Struct.new(:foo, :bar)
  def thing
  end
end

Compliant Code Examples

Foo = Struct.new(:foo, :bar)