classification#parent_id = nil when no parents

[kbrock]

We used to have parent_id=0 when there was no parent.
Rails prefers to use a nil

This is in response to @Fryguy comment in ManageIQ/manageiq#17210

[miq-bot]

Checked commit kbrock@2f21d18 with ruby 2.3.3, rubocop 0.52.1, haml-lint 0.20.0, and yamllint 1.10.0
2 files checked, 2 offenses detected

db/migrate/20181130203334_classification_parent_null.rb

• ❗ - Line 12, Col 45 - Rails/SkipsModelValidations - Avoid using update_all because it skips validations.
• ❗ - Line 7, Col 43 - Rails/SkipsModelValidations - Avoid using update_all because it skips validations.

[cben]

Kudos for not giving up on simplifying classifications! 🙇‍♂️

LGTM. Needs matching change in core of course.

[Fryguy]

@carbonin @bdunne Please review.

@kbrock Is there a correspnding change to core that sets the value to nil as well so new 0 values aren't introduced after this is merged?

[kbrock]

@Fryguy do you want the code to handle the parent_id = 0 case, or do we assume the people have run the migrations? (I'm thinking we should handle parent_id = 0)

e.g.:

class Classification
  scope :is_category, -> { where(:parent_id => [0, nil]) }

  def category?
    parent_id == 0 || parent_id.nil?
  end
end

Currently it only supports :parent_id => 0. The alternative would be to change this to :parent_id => nil.

[Fryguy]

Once the migration is merged we can safely assume that the user has run through it. They can't use a release of the code without migrating first.