generates 2 validations for a multi-column unique constraint

[urkle]

I have this schema

  create_table "authorizations" do |t|
    t.integer  "user_id",               null: false, index: {name: "index_authorizations_on_user_id"}, foreign_key: {references: "users", name: "fk_authorizations_user_id", on_update: :restrict, on_delete: :cascade}
    t.integer  "client_application_id", null: false, index: {name: "index_authorizations_on_client_application_id_and_nonce", with: ["nonce"], unique: true}, foreign_key: {references: "client_applications", name: "fk_authorizations_client_application_id", on_update: :restrict, on_delete: :cascade}
    t.string   "code",                  null: false, index: {name: "index_authorizations_on_code", unique: true}
    t.string   "nonce",                 null: false
end

Here is the list of validations generated

[schema_validations] Authorization.validates_presence_of :code
[schema_validations] Authorization.validates_uniqueness_of :code, :allow_nil=>true, :if=>#<Proc:0x000000063a24c8@/home/urkle/.rvm/gems/ruby-2.1.5@rails4/gems/schema_validations-1.4.0/lib/schema_validations/active_record/validations.rb:167>
[schema_validations] Authorization.validates_presence_of :nonce
[schema_validations] Authorization.validates_uniqueness_of :nonce, :scope=>[:client_application_id], :allow_nil=>true, :if=>#<Proc:0x00000006387bc8@/home/urkle/.rvm/gems/ruby-2.1.5@rails4/gems/schema_validations-1.4.0/lib/schema_validations/active_record/validations.rb:167>
[schema_validations] Authorization.validates_presence_of :user
[schema_validations] Authorization.validates_presence_of :client_application
[schema_validations] Authorization.validates_uniqueness_of :client_application_id, :scope=>[:nonce], :allow_nil=>true, :if=>#<Proc:0x0000000637cac0@/home/urkle/.rvm/gems/ruby-2.1.5@rails4/gems/schema_validations-1.4.0/lib/schema_validations/active_record/validations.rb:167>

Notice the two validations created for the multi-column constraint. One for client_app_id, nonce.. And one for nonce, client_app_id

Also it seems odd that a validation with "allow_nil: true" would be generated when clearly I do not allow nils.

[urkle]

BTW.. I'm using schema_validations 1.4.0

And this ends up causing ActiveRecord to issue 2 DB checks

  Authorization Exists (1.2ms)  SELECT  1 AS one FROM "authorizations" WHERE ("authorizations"."nonce" = 'test123' AND "authorizations"."client_application_id" = 1) LIMIT 1
  Authorization Exists (1.1ms)  SELECT  1 AS one FROM "authorizations" WHERE ("authorizations"."client_application_id" = 1 AND "authorizations"."nonce" = 'test123') LIMIT 1

Also, the "code" validations causes 2 queries to also be issued.

  Authorization Exists (0.8ms)  SELECT  1 AS one FROM "authorizations" WHERE "authorizations"."code" = $1 LIMIT 1  [["code", "040cd859525d7dcd42b4ab99fa7b23ae0d9ec0bc472a730874f2d810bd4ef0ec"]]
  Authorization Exists (1.0ms)  SELECT  1 AS one FROM "authorizations" WHERE "authorizations"."code" = '040cd859525d7dcd42b4ab99fa7b23ae0d9ec0bc472a730874f2d810bd4ef0ec' LIMIT 1

[ronen]

@urkle thanks for the report and sorry for the slow reply.

You're right, schema_validations ought to be able to optimize away those duplicate validations. Though I must admit I'm not certain whether there's complete symmetry between these two:

validates :a, uniqueness: { scope: :b }
validates :b, uniqueness: { scope: :a }

And if they're not symmetric, how should schema_validations choose which to issue?

(BTW Using modern syntax above, see #33)

And agreed it's odd to have allow_nil when nil isn't allowed.

Unfortunately no time for me to dive into these right now--especially since there's a workaround: disable schema_validations for the offending column(s) and manually validate them appropriately--but PRs happily accepted!