Populate remaning dismissal information

The post-deployment migration is required for clean-up.

changelogs/unreleased/262112_populate_remaining_dismissal_information.yml

+---
+title: Add migration to populate remaining dismissal information for vulnerabilities
+merge_request: 48472
+author:
+type: added

db/post_migrate/20201124122817_populate_remaining_missing_dismissal_information_for_vulnerabilities.rb

+# frozen_string_literal: true
+
+class PopulateRemainingMissingDismissalInformationForVulnerabilities < ActiveRecord::Migration[6.0]
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    Gitlab::BackgroundMigration.steal('PopulateMissingVulnerabilityDismissalInformation')
+
+    ::Gitlab::BackgroundMigration::PopulateMissingVulnerabilityDismissalInformation::Vulnerability.broken.each_batch(of: 100) do |batch, index|
+      vulnerability_ids = batch.pluck(:id)
+
+      ::Gitlab::BackgroundMigration::PopulateMissingVulnerabilityDismissalInformation.new.perform(*vulnerability_ids)
+    end
+  end
+
+  def down
+    # no-op
+  end
+end

db/schema_migrations/20201124122817

+1113642dfc9069dcea01ac12b1653dfcf67b3aea449538e9747d3bc857ce88d8
\ No newline at end of file

spec/migrations/populate_remaining_missing_dismissal_information_for_vulnerabilities_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+require_migration!
+
+RSpec.describe PopulateRemainingMissingDismissalInformationForVulnerabilities do
+  let(:users) { table(:users) }
+  let(:namespaces) { table(:namespaces) }
+  let(:projects) { table(:projects) }
+  let(:vulnerabilities) { table(:vulnerabilities) }
+
+  let(:user) { users.create!(name: 'test', email: 'test@example.com', projects_limit: 5) }
+  let(:namespace) { namespaces.create!(name: 'gitlab', path: 'gitlab-org') }
+  let(:project) { projects.create!(namespace_id: namespace.id, name: 'foo') }
+
+  let(:states) { { detected: 1, dismissed: 2, resolved: 3, confirmed: 4 } }
+  let!(:vulnerability_1) { vulnerabilities.create!(title: 'title', state: states[:detected], severity: 0, confidence: 5, report_type: 2, project_id: project.id, author_id: user.id) }
+  let!(:vulnerability_2) { vulnerabilities.create!(title: 'title', state: states[:dismissed], severity: 0, confidence: 5, report_type: 2, project_id: project.id, author_id: user.id) }
+  let!(:vulnerability_3) { vulnerabilities.create!(title: 'title', state: states[:resolved], severity: 0, confidence: 5, report_type: 2, project_id: project.id, author_id: user.id) }
+  let!(:vulnerability_4) { vulnerabilities.create!(title: 'title', state: states[:confirmed], severity: 0, confidence: 5, report_type: 2, project_id: project.id, author_id: user.id) }
+
+  describe '#perform' do
+    it 'calls the background migration class instance with broken vulnerability IDs' do
+      expect_next_instance_of(::Gitlab::BackgroundMigration::PopulateMissingVulnerabilityDismissalInformation) do |migrator|
+        expect(migrator).to receive(:perform).with(vulnerability_2.id)
+      end
+
+      migrate!
+    end
+  end
+end