From 8afc9bb0c349054727b0f158654eeb6c1dcba7a9 Mon Sep 17 00:00:00 2001
From: rhymes <rhymesete@gmail.com>
Date: Mon, 6 Jul 2020 18:15:56 +0200
Subject: [PATCH] [deploy] Add unique indexes to follows - part 7 (#8215)

---
 app/models/follow.rb                                |  2 +-
 ...d_unique_index_to_follows_followable_follower.rb | 13 +++++++++++++
 db/schema.rb                                        |  3 ++-
 spec/models/follow_spec.rb                          |  3 +++
 4 files changed, 19 insertions(+), 2 deletions(-)
 create mode 100644 db/migrate/20200702143618_add_unique_index_to_follows_followable_follower.rb

diff --git a/app/models/follow.rb b/app/models/follow.rb
index 4cfe43545..826d9fa1c 100644
--- a/app/models/follow.rb
+++ b/app/models/follow.rb
@@ -34,7 +34,7 @@ class Follow < ApplicationRecord
   after_create_commit :create_chat_channel
   before_destroy :modify_chat_channel_status
 
-  validates :followable_id, uniqueness: { scope: %i[followable_type follower_id] }
+  validates :followable_id, uniqueness: { scope: %i[followable_type follower_id follower_type] }
   validates :subscription_status, inclusion: { in: %w[all_articles none] }
 
   def self.need_new_follower_notification_for?(followable_type)
diff --git a/db/migrate/20200702143618_add_unique_index_to_follows_followable_follower.rb b/db/migrate/20200702143618_add_unique_index_to_follows_followable_follower.rb
new file mode 100644
index 000000000..23042d4a7
--- /dev/null
+++ b/db/migrate/20200702143618_add_unique_index_to_follows_followable_follower.rb
@@ -0,0 +1,13 @@
+class AddUniqueIndexToFollowsFollowableFollower < ActiveRecord::Migration[6.0]
+  disable_ddl_transaction!
+
+  def change
+    add_index(
+      :follows,
+      %i[followable_id followable_type follower_id follower_type],
+      unique: true,
+      algorithm: :concurrently,
+      name: :index_follows_on_followable_and_follower
+    )
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 775e0fa1d..dbe66b4ca 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2020_06_18_212422) do
+ActiveRecord::Schema.define(version: 2020_07_02_143618) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -564,6 +564,7 @@ ActiveRecord::Schema.define(version: 2020_06_18_212422) do
     t.string "subscription_status", default: "all_articles", null: false
     t.datetime "updated_at"
     t.index ["created_at"], name: "index_follows_on_created_at"
+    t.index ["followable_id", "followable_type", "follower_id", "follower_type"], name: "index_follows_on_followable_and_follower", unique: true
     t.index ["followable_id", "followable_type"], name: "fk_followables"
     t.index ["follower_id", "follower_type"], name: "fk_follows"
   end
diff --git a/spec/models/follow_spec.rb b/spec/models/follow_spec.rb
index 39a2e89f4..1502fbf75 100644
--- a/spec/models/follow_spec.rb
+++ b/spec/models/follow_spec.rb
@@ -5,7 +5,10 @@ RSpec.describe Follow, type: :model do
   let(:user_2) { create(:user) }
 
   describe "validations" do
+    subject { user.follow(user_2) }
+
     it { is_expected.to validate_inclusion_of(:subscription_status).in_array(%w[all_articles none]) }
+    it { is_expected.to validate_uniqueness_of(:followable_id).scoped_to(%i[followable_type follower_id follower_type]) }
   end
 
   it "follows user" do