Create IssueEmailParticipant model

- create issue_email_participants table
- create model with associations and specs

app/models/issue.rb

@@ -56,6 +56,7 @@ class Issue < ApplicationRecord
     dependent: :delete_all # rubocop:disable Cop/ActiveRecordDependent
 
   has_many :issue_assignees
+  has_many :issue_email_participants
   has_many :assignees, class_name: "User", through: :issue_assignees
   has_many :zoom_meetings
   has_many :user_mentions, class_name: "IssueUserMention", dependent: :delete_all # rubocop:disable Cop/ActiveRecordDependent

app/models/issue_email_participant.rb

+# frozen_string_literal: true
+
+class IssueEmailParticipant < ApplicationRecord
+  belongs_to :issue
+
+  validates :email, presence: true, uniqueness: { scope: [:issue_id] }
+  validates :issue, presence: true
+  validate :validate_email_format
+
+  def validate_email_format
+    self.errors.add(:email, I18n.t(:invalid, scope: 'valid_email.validations.email')) unless ValidateEmail.valid?(self.email)
+  end
+end

changelogs/unreleased/225293-emaill-participants.yml

+---
+title: Add issue_email_participants table and related model
+merge_request: 42943
+author:
+type: other

db/migrate/20200922052316_create_issue_email_participants.rb

+# frozen_string_literal: true
+
+class CreateIssueEmailParticipants < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    unless table_exists?(:issue_email_participants)
+      with_lock_retries do
+        create_table :issue_email_participants do |t|
+          t.references :issue, index: false, null: false, foreign_key: { on_delete: :cascade }
+          t.datetime_with_timezone :created_at, null: false
+          t.datetime_with_timezone :updated_at, null: false
+          t.text :email, null: false
+
+          t.index [:issue_id, :email], unique: true
+        end
+      end
+
+      add_text_limit(:issue_email_participants, :email, 255)
+    end
+  end
+
+  def down
+    with_lock_retries do
+      drop_table :issue_email_participants
+    end
+  end
+end

db/schema_migrations/20200922052316

+384d022662437de21b4b3b97bf2f1dec2925be6afe4b62828c97dc9b3b3fc77c
\ No newline at end of file

db/structure.sql

@@ -12676,6 +12676,24 @@ CREATE TABLE issue_assignees (
     issue_id integer NOT NULL
 );
 
+CREATE TABLE issue_email_participants (
+    id bigint NOT NULL,
+    issue_id bigint NOT NULL,
+    created_at timestamp with time zone NOT NULL,
+    updated_at timestamp with time zone NOT NULL,
+    email text NOT NULL,
+    CONSTRAINT check_2c321d408d CHECK ((char_length(email) <= 255))
+);
+
+CREATE SEQUENCE issue_email_participants_id_seq
+    START WITH 1
+    INCREMENT BY 1
+    NO MINVALUE
+    NO MAXVALUE
+    CACHE 1;
+
+ALTER SEQUENCE issue_email_participants_id_seq OWNED BY issue_email_participants.id;
+
 CREATE TABLE issue_links (
     id integer NOT NULL,
     source_id integer NOT NULL,
@@ -17447,6 +17465,8 @@ ALTER TABLE ONLY ip_restrictions ALTER COLUMN id SET DEFAULT nextval('ip_restric
 
 ALTER TABLE ONLY issuable_severities ALTER COLUMN id SET DEFAULT nextval('issuable_severities_id_seq'::regclass);
 
+ALTER TABLE ONLY issue_email_participants ALTER COLUMN id SET DEFAULT nextval('issue_email_participants_id_seq'::regclass);
+
 ALTER TABLE ONLY issue_links ALTER COLUMN id SET DEFAULT nextval('issue_links_id_seq'::regclass);
 
 ALTER TABLE ONLY issue_metrics ALTER COLUMN id SET DEFAULT nextval('issue_metrics_id_seq'::regclass);
@@ -18565,6 +18585,9 @@ ALTER TABLE ONLY ip_restrictions
 ALTER TABLE ONLY issuable_severities
     ADD CONSTRAINT issuable_severities_pkey PRIMARY KEY (id);
 
+ALTER TABLE ONLY issue_email_participants
+    ADD CONSTRAINT issue_email_participants_pkey PRIMARY KEY (id);
+
 ALTER TABLE ONLY issue_links
     ADD CONSTRAINT issue_links_pkey PRIMARY KEY (id);
 
@@ -20349,6 +20372,8 @@ CREATE UNIQUE INDEX index_issue_assignees_on_issue_id_and_user_id ON issue_assig
 
 CREATE INDEX index_issue_assignees_on_user_id ON issue_assignees USING btree (user_id);
 
+CREATE UNIQUE INDEX index_issue_email_participants_on_issue_id_and_email ON issue_email_participants USING btree (issue_id, email);
+
 CREATE INDEX index_issue_links_on_source_id ON issue_links USING btree (source_id);
 
 CREATE UNIQUE INDEX index_issue_links_on_source_id_and_target_id ON issue_links USING btree (source_id, target_id);
@@ -22621,6 +22646,9 @@ ALTER TABLE ONLY user_synced_attributes_metadata
 ALTER TABLE ONLY project_authorizations
     ADD CONSTRAINT fk_rails_0f84bb11f3 FOREIGN KEY (project_id) REFERENCES projects(id) ON DELETE CASCADE;
 
+ALTER TABLE ONLY issue_email_participants
+    ADD CONSTRAINT fk_rails_0fdfd8b811 FOREIGN KEY (issue_id) REFERENCES issues(id) ON DELETE CASCADE;
+
 ALTER TABLE ONLY merge_request_context_commits
     ADD CONSTRAINT fk_rails_0fe0039f60 FOREIGN KEY (merge_request_id) REFERENCES merge_requests(id) ON DELETE CASCADE;
 

spec/factories/issue_email_participants.rb

+# frozen_string_literal: true
+
+FactoryBot.define do
+  factory :issue_email_participant do
+    issue
+    email { generate(:email) }
+  end
+end

spec/lib/gitlab/import_export/all_models.yml

@@ -51,6 +51,7 @@ issues:
 - status_page_published_incident
 - namespace
 - note_authors
+- issue_email_participants
 events:
 - author
 - project

spec/models/issue_email_participant_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe IssueEmailParticipant do
+  describe "Associations" do
+    it { is_expected.to belong_to(:issue) }
+  end
+
+  describe 'Validations' do
+    subject { build(:issue_email_participant) }
+
+    it { is_expected.to validate_presence_of(:issue) }
+    it { is_expected.to validate_presence_of(:email) }
+    it { is_expected.to validate_uniqueness_of(:email).scoped_to([:issue_id]) }
+
+    it_behaves_like 'an object with RFC3696 compliant email-formated attributes', :email
+  end
+end

spec/models/issue_spec.rb

@@ -28,6 +28,7 @@ RSpec.describe Issue do
     it { is_expected.to have_and_belong_to_many(:prometheus_alert_events) }
     it { is_expected.to have_and_belong_to_many(:self_managed_prometheus_alert_events) }
     it { is_expected.to have_many(:prometheus_alerts) }
+    it { is_expected.to have_many(:issue_email_participants) }
 
     describe 'versions.most_recent' do
       it 'returns the most recent version' do