Add migration to add not null constraints to releases timestamps

Backfill null updated_at rows with created_at

changelogs/unreleased/backfill-releases-updated-at.yml

+---
+title: Backfill releases table updated_at column and add not null constraints to created_at and updated_at
+merge_request: 17400
+author:
+type: fixed

db/migrate/20190920194925_backfill_releases_table_updated_at_and_add_not_null_constraints_to_timestamps.rb

+# frozen_string_literal: true
+
+class BackfillReleasesTableUpdatedAtAndAddNotNullConstraintsToTimestamps < ActiveRecord::Migration[5.2]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    change_column_null(:releases, :created_at, false, Time.zone.now)
+
+    update_column_in_batches(:releases, :updated_at, Arel.sql('created_at')) do |table, query|
+      query.where(table[:updated_at].eq(nil))
+    end
+
+    change_column_null(:releases, :updated_at, false, Time.zone.now)
+  end
+
+  def down
+    change_column_null(:releases, :updated_at, true)
+    change_column_null(:releases, :created_at, true)
+  end
+end

db/schema.rb

@@ -3137,8 +3137,8 @@ ActiveRecord::Schema.define(version: 2019_09_27_074328) do
     t.string "tag"
     t.text "description"
     t.integer "project_id"
-    t.datetime "created_at"
-    t.datetime "updated_at"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
     t.text "description_html"
     t.integer "cached_markdown_version"
     t.integer "author_id"

spec/migrations/backfill_releases_table_updated_at_and_add_not_null_constraints_to_timestamps_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+require Rails.root.join('db', 'migrate', '20190920194925_backfill_releases_table_updated_at_and_add_not_null_constraints_to_timestamps.rb')
+
+describe BackfillReleasesTableUpdatedAtAndAddNotNullConstraintsToTimestamps, :migration do
+  let(:releases)   { table(:releases) }
+  let(:namespaces) { table(:namespaces) }
+  let(:projects)   { table(:projects) }
+
+  subject(:migration) { described_class.new }
+
+  it 'fills null updated_at rows with the value of created_at' do
+    created_at_a = Time.zone.parse('2014-03-11T04:30:00Z')
+    created_at_b = Time.zone.parse('2019-09-10T12:00:00Z')
+    namespace = namespaces.create(name: 'foo', path: 'foo')
+    project = projects.create!(namespace_id: namespace.id)
+    release_a = releases.create!(project_id: project.id,
+                                 released_at: Time.zone.parse('2014-12-10T06:00:00Z'),
+                                 created_at: created_at_a)
+    release_b = releases.create!(project_id: project.id,
+                                 released_at: Time.zone.parse('2019-09-11T06:00:00Z'),
+                                 created_at: created_at_b)
+    release_a.update!(updated_at: nil)
+    release_b.update!(updated_at: nil)
+
+    disable_migrations_output { migrate! }
+
+    release_a.reload
+    release_b.reload
+    expect(release_a.updated_at).to eq(created_at_a)
+    expect(release_b.updated_at).to eq(created_at_b)
+  end
+
+  it 'does not change updated_at columns with a value' do
+    created_at_a = Time.zone.parse('2014-03-11T04:30:00Z')
+    updated_at_a = Time.zone.parse('2015-01-16T10:00:00Z')
+    created_at_b = Time.zone.parse('2019-09-10T12:00:00Z')
+    namespace = namespaces.create(name: 'foo', path: 'foo')
+    project = projects.create!(namespace_id: namespace.id)
+    release_a = releases.create!(project_id: project.id,
+                                 released_at: Time.zone.parse('2014-12-10T06:00:00Z'),
+                                 created_at: created_at_a,
+                                 updated_at: updated_at_a)
+    release_b = releases.create!(project_id: project.id,
+                                 released_at: Time.zone.parse('2019-09-11T06:00:00Z'),
+                                 created_at: created_at_b)
+    release_b.update!(updated_at: nil)
+
+    disable_migrations_output { migrate! }
+
+    release_a.reload
+    release_b.reload
+    expect(release_a.updated_at).to eq(updated_at_a)
+    expect(release_b.updated_at).to eq(created_at_b)
+  end
+end