[deploy] Add relations and foreign keys between Podcast related models (#9888)

* Add proper relations and dependent clauses

* Add foreign key between podcast_episodes and podcasts

.rubocop_todo.yml

@@ -26,8 +26,6 @@ Rails/HasManyOrHasOneDependent:
     - 'app/models/article.rb'
     - 'app/models/concerns/user_subscription_sourceable.rb'
     - 'app/models/organization.rb'
-    - 'app/models/podcast.rb'
-    - 'app/models/podcast_episode.rb'
     - 'app/models/user.rb'
 
 # Offense count: 4

app/models/podcast.rb

@@ -1,8 +1,8 @@
 class Podcast < ApplicationRecord
   resourcify
 
-  has_many :podcast_episodes
   belongs_to :creator, class_name: "User", inverse_of: :created_podcasts, optional: true
+  has_many :podcast_episodes, dependent: :destroy
 
   mount_uploader :image, ProfileImageUploader
   mount_uploader :pattern_image, ProfileImageUploader

app/models/podcast_episode.rb

@@ -15,7 +15,7 @@ class PodcastEpisode < ApplicationRecord
   delegate :published, to: :podcast
 
   belongs_to :podcast
-  has_many :comments, as: :commentable, inverse_of: :commentable
+  has_many :comments, as: :commentable, inverse_of: :commentable, dependent: :nullify
 
   mount_uploader :image, ProfileImageUploader
   mount_uploader :social_image, ProfileImageUploader

db/migrate/20200820093731_add_missing_foreign_keys_to_podcast_episodes.rb

@@ -0,0 +1,5 @@
+class AddMissingForeignKeysToPodcastEpisodes < ActiveRecord::Migration[6.0]
+  def change
+    add_foreign_key :podcast_episodes, :podcasts, column: :podcast_id, on_delete: :cascade, validate: false
+  end
+end

db/migrate/20200820093752_validate_add_missing_foreign_keys_to_podcast_episodes.rb

@@ -0,0 +1,5 @@
+class ValidateAddMissingForeignKeysToPodcastEpisodes < ActiveRecord::Migration[6.0]
+  def change
+    validate_foreign_key :podcast_episodes, :podcasts
+  end
+end

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_08_18_163834) do
+ActiveRecord::Schema.define(version: 2020_08_20_093752) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "citext"
@@ -1378,6 +1378,7 @@ ActiveRecord::Schema.define(version: 2020_08_18_163834) do
   add_foreign_key "oauth_access_tokens", "oauth_applications", column: "application_id"
   add_foreign_key "oauth_access_tokens", "users", column: "resource_owner_id"
   add_foreign_key "page_views", "articles", on_delete: :cascade
+  add_foreign_key "podcast_episodes", "podcasts", on_delete: :cascade
   add_foreign_key "podcasts", "users", column: "creator_id"
   add_foreign_key "poll_options", "polls", on_delete: :cascade
   add_foreign_key "poll_skips", "polls", on_delete: :cascade

spec/models/podcast_episode_spec.rb

@@ -3,12 +3,19 @@ require "rails_helper"
 RSpec.describe PodcastEpisode, type: :model do
   let(:podcast_episode) { create(:podcast_episode) }
 
-  it { is_expected.to validate_presence_of(:title) }
-  it { is_expected.to validate_presence_of(:slug) }
-  it { is_expected.to validate_presence_of(:media_url) }
-  it { is_expected.to validate_presence_of(:guid) }
-
   describe "validations" do
+    describe "builtin validations" do
+      subject { podcast_episode }
+
+      it { is_expected.to belong_to(:podcast) }
+      it { is_expected.to have_many(:comments).inverse_of(:commentable).dependent(:nullify) }
+
+      it { is_expected.to validate_presence_of(:guid) }
+      it { is_expected.to validate_presence_of(:media_url) }
+      it { is_expected.to validate_presence_of(:slug) }
+      it { is_expected.to validate_presence_of(:title) }
+    end
+
     # Couldn't use shoulda matchers for these tests because:
     # Shoulda uses `save(validate: false)` which skips validations, but runs callbacks
     # So an invalid record is saved and the elasticsearch callback fails because there's no associated podcast

spec/models/podcast_spec.rb

@@ -3,12 +3,6 @@ require "rails_helper"
 RSpec.describe Podcast, type: :model do
   let(:podcast) { create(:podcast) }
 
-  it { is_expected.to validate_presence_of(:image) }
-  it { is_expected.to validate_presence_of(:slug) }
-  it { is_expected.to validate_presence_of(:title) }
-  it { is_expected.to validate_presence_of(:main_color_hex) }
-  it { is_expected.to validate_presence_of(:feed_url) }
-
   it "has a creator" do
     user = build(:user)
     pod = create(:podcast, creator: user)
@@ -24,6 +18,19 @@ RSpec.describe Podcast, type: :model do
   end
 
   describe "validations" do
+    describe "builtin validations" do
+      subject { podcast }
+
+      it { is_expected.to belong_to(:creator).class_name("User").inverse_of(:created_podcasts).optional }
+      it { is_expected.to have_many(:podcast_episodes).dependent(:destroy) }
+
+      it { is_expected.to validate_presence_of(:feed_url) }
+      it { is_expected.to validate_presence_of(:image) }
+      it { is_expected.to validate_presence_of(:main_color_hex) }
+      it { is_expected.to validate_presence_of(:slug) }
+      it { is_expected.to validate_presence_of(:title) }
+    end
+
     # Couldn't use shoulda uniqueness matchers for these tests because:
     # Shoulda uses `save(validate: false)` which skips validations
     # So an invalid record is trying to be saved but fails because of the db constraints