Rails/UniqueValidationWithoutIndex: False positive when there's no t.index

[igorlvicente]

I don't really know what is the problem, but I saw the spec of this cop and found no example that uses add_index rather than t.index on schema.rb, so I guess that could be the reason.

I tried the rubocop-rails in the versions 2.4 and 2.5

---

Expected behavior

No errors raised

Actual behavior

Output:

rubocop -d -c ./.rubocop.yml app/models/MODEL_NAMESPACE/MODEL_NAME.rb 
configuration from /home/USER/REPO/.rubocop.yml
configuration from /home/USER/.rbenv/versions/2.5.5/lib/ruby/gems/2.5.0/gems/rubocop-rails-2.5.0/config/default.yml
configuration from /home/USER/.rbenv/versions/2.5.5/lib/ruby/gems/2.5.0/gems/rubocop-rails-2.5.0/config/default.yml
Default configuration from /home/USER/.rbenv/versions/2.5.5/lib/ruby/gems/2.5.0/gems/rubocop-0.78.0/config/default.yml
configuration from /home/USER/.rbenv/versions/2.5.5/lib/ruby/gems/2.5.0/gems/rubocop-rspec-1.37.1/config/default.yml
configuration from /home/USER/.rbenv/versions/2.5.5/lib/ruby/gems/2.5.0/gems/rubocop-rspec-1.37.1/config/default.yml
Inspecting 1 file
Scanning /home/USER/REPO/app/models/customer_success/contact.rb
C

Offenses:

app/models/NAMESPACE/MODEL.rb:2:1: C: Layout/EmptyLineAfterMagicComment: Add an empty line after magic comments. (https://rubystyle.guide#separate-magic-comments-from-code)
# == Schema Information
^
app/models/NAMESPACE/MODEL.rb:34:5: C: Rails/UniqueValidationWithoutIndex: Uniqueness validation should be with a unique index.
    validates :phone, phone: true, allow_blank: true, uniqueness: true
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

1 file inspected, 2 offenses detected
Finished in 1.7771203410002272 seconds

My schema.rb related to the model:

create_table "TABLE_NAME", force: :cascade do |t|
    t.string   "name",              limit: 255
    t.datetime "created_at",                                      null: false
    t.datetime "updated_at",                                      null: false
    t.integer  "salon_id",          limit: 4
    t.boolean  "in_charge_finance",               default: false
    t.text     "observation",       limit: 65535
  end

  add_index "TABLE_NAME", ["phone"], name: "index_TABLE_NAME_on_phone", unique: true, using: :btree
  add_index "TABLE_NAME", ["salon_id"], name: "index_TABLE_NAME_on_salon_id", using: :btree

Steps to reproduce the problem

Having a add_index instead of a t.index on schema.rb, I guess.

RuboCop version

$ [bundle exec] rubocop -V
0.78.0 (using Parser 2.6.5.0, running on ruby 2.5.5 x86_64-linux)

[rodrigomanhaes]

Same issue here using add_index or t.index.

[koic]

Thank you for the feedback. AFAIK, the expression of index written in db/schema.rb changes between Rails 4 and Rails 5. And The Rails core team currently maintains versions Rails 6.0.Z and 5.2.Z.
https://guides.rubyonrails.org/maintenance_policy.html

Therefore, RuboCop Rails will drop support for Rails 4 in near future (Maybe 5.0 and 5.1 will be supported for a while). So, I will consider whether to implement the feature whose support will be cut in near future.

[koic]

This issue resolved by #222 because Rails 4.0 and Rails 4.1 support will drop shortly, but Rails 4.2 may be a bit ahead. Thank you.

[GoudekettingRM]

I just ran into the same issue using the index: true option.

t.string :key, null: false, index: true

Not sure if it is because of old versions, could be the cause. I just cannot update them 🥲

versions:

• ruby: 2.7.4
• rails: 5.2.3
• rubocop: 1.27.0
• rubocop-rails: 2.5.2

[Piioo]

I just ran into the same issue using the index: true option.

t.string :key, null: false, index: true

Not sure if it is because of old versions, could be the cause. I just cannot update them 🥲

versions:

• ruby: 2.7.4
• rails: 5.2.3
• rubocop: 1.27.0
• rubocop-rails: 2.5.2

Have the same problem with:
Rails 7.0.4.3
ruby 3.2.2
rubocop 1.50.0