Include post migrations when loading the schema

See merge request gitlab-org/gitlab-ce!21689

changelogs/unreleased/force-post-migration-dir-schema-load.yml

+---
+title: Ensure the schema is loaded with post_migrations included
+merge_request: 21689
+author:
+type: changed

config/initializers/0_post_deployment_migrations.rb

 # Post deployment migrations are included by default. This file must be loaded
 # before other initializers as Rails may otherwise memoize a list of migrations
 # excluding the post deployment migrations.
-unless ENV['SKIP_POST_DEPLOYMENT_MIGRATIONS']
-  Rails.application.config.paths['db'].each do |db_path|
-    path = Rails.root.join(db_path, 'post_migrate').to_s
-
-    Rails.application.config.paths['db/migrate'] << path
-
-    # Rails memoizes migrations at certain points where it won't read the above
-    # path just yet. As such we must also update the following list of paths.
-    ActiveRecord::Migrator.migrations_paths << path
-  end
-end
+Gitlab::Database.add_post_migrate_path_to_rails

lib/gitlab/database.rb

@@ -249,5 +249,21 @@ module Gitlab
     end
     private_class_method :database_version
+
+    def self.add_post_migrate_path_to_rails(force: false)
+      return if ENV['SKIP_POST_DEPLOYMENT_MIGRATIONS'] && !force
+
+      Rails.application.config.paths['db'].each do |db_path|
+        path = Rails.root.join(db_path, 'post_migrate').to_s
+
+        unless Rails.application.config.paths['db/migrate'].include? path
+          Rails.application.config.paths['db/migrate'] << path
+
+          # Rails memoizes migrations at certain points where it won't read the above
+          # path just yet. As such we must also update the following list of paths.
+          ActiveRecord::Migrator.migrations_paths << path
+        end
+      end
+    end
   end
 end

lib/tasks/gitlab/db.rake

@@ -51,6 +51,8 @@ namespace :gitlab do
       if ActiveRecord::Base.connection.tables.count > 1
         Rake::Task['db:migrate'].invoke
       else
+        # Add post-migrate paths to ensure we mark all migrations as up
+        Gitlab::Database.add_post_migrate_path_to_rails(force: true)
         Rake::Task['db:schema:load'].invoke
         Rake::Task['db:seed_fu'].invoke
       end

spec/tasks/gitlab/db_rake_spec.rb

@@ -61,6 +61,39 @@ describe 'gitlab:db namespace rake task' do
       expect(Rake::Task['db:migrate']).not_to receive(:invoke)
       expect { run_rake_task('gitlab:db:configure') }.to raise_error(RuntimeError, 'error')
     end
+
+    context 'SKIP_POST_DEPLOYMENT_MIGRATIONS environment variable set' do
+      let(:rails_paths) { { 'db' => ['db'], 'db/migrate' => ['db/migrate'] } }
+
+      before do
+        allow(ENV).to receive(:[]).and_call_original
+        allow(ENV).to receive(:[]).with('SKIP_POST_DEPLOYMENT_MIGRATIONS').and_return true
+
+        # Our environment has already been loaded, so we need to pretend like post_migrations were not
+        allow(Rails.application.config).to receive(:paths).and_return(rails_paths)
+        allow(ActiveRecord::Migrator).to receive(:migrations_paths).and_return(rails_paths['db/migrate'].dup)
+      end
+
+      it 'adds post deployment migrations before schema load if the schema is not already loaded' do
+        allow(ActiveRecord::Base.connection).to receive(:tables).and_return([])
+        expect(Gitlab::Database).to receive(:add_post_migrate_path_to_rails).and_call_original
+        expect(Rake::Task['db:schema:load']).to receive(:invoke)
+        expect(Rake::Task['db:seed_fu']).to receive(:invoke)
+        expect(Rake::Task['db:migrate']).not_to receive(:invoke)
+        expect { run_rake_task('gitlab:db:configure') }.not_to raise_error
+        expect(rails_paths['db/migrate'].include?(File.join(Rails.root, 'db', 'post_migrate'))).to be(true)
+      end
+
+      it 'ignores post deployment migrations  when schema has already been loaded' do
+        allow(ActiveRecord::Base.connection).to receive(:tables).and_return(%w[table1 table2])
+        expect(Rake::Task['db:migrate']).to receive(:invoke)
+        expect(Gitlab::Database).not_to receive(:add_post_migrate_path_to_rails)
+        expect(Rake::Task['db:schema:load']).not_to receive(:invoke)
+        expect(Rake::Task['db:seed_fu']).not_to receive(:invoke)
+        expect { run_rake_task('gitlab:db:configure') }.not_to raise_error
+        expect(rails_paths['db/migrate'].include?(File.join(Rails.root, 'db', 'post_migrate'))).to be(false)
+      end
+    end
   end
   def run_rake_task(task_name)