#empty? does not update if error added via #errors.add(...)

[richardboehme]

Using #empty? is a common pattern to check if a form object has any errors or not. For example this method is also used when calling #present?. It should return true if there are no errors and false otherwise.

Currently I'm working on an application that requires adding errors to the form after it was validated. However, adding an error after validating the form does not change the status of #empty?. The following example demonstrates the problem:

class Form < Reform::Form
  property :example
end

form = Form.new(OpenStruct.new)
form.validate({example: 1})
form.errors.empty? # => true
form.errors.add(:example, :invalid)
form.errors.empty? # => true

The last call to #empty? should return false. The same issue also exists when adding a new error to a nested form.

Currently #empty? only checks for the @success instance variable. My first idea was to set this instance variable to false once #add is called on the form's errors. However, this won't work for nested forms because the "parent"-form still does not know about the nested error. Maybe there is another better way of solving this issue?

The current workaround for me is to call validate({}) after adding the errors to ensure the new errors are "recognized" by the form.

[richardboehme]

Ok calling revalidating the form as a workaround has it's own problems. Just want to share my current workaround patch that seems to work:

module ReformErrorsPatch
  def empty?
    @form.schema.each(twin: true) do |dfn|
      Disposable::Twin::PropertyProcessor.new(dfn, @form).() do |_frm, i|
        form_obj = i ? @form.send(dfn[:name])[i] : @form.send(dfn[:name])
        return false unless form_obj.errors.empty?
      end
    end
    messages.empty?
  end
end

Rails.application.config.to_prepare do
  Reform::Form::ActiveModel::Validations::Result::ResultErrors.prepend(ReformErrorsPatch)
end

This definitely comes with some performance penalty. I guess there is a simpler way to do this.