User::getAnonymousUser() takes 13ms due to ContentEntityBase::setDefaultLangcode()

Shortcut all this for entity types that we know aren't translatable, without completely removing the ability to make them translatable again from contrib. Not sure the best approach for this.

Well, in case the logic is in the content entity class, people could, and we maybe should try to make that easy, override those methods to make it translatable again.

The related #2345611-70: Load user entity in Cookie AuthenticationProvider instead of using manual queries shows that we need language to access roles in authentication
suppose we need optimize access to entity values always providing langcode

Can we just do this?

I didn't profile this, but I verified that it did go into the first if().

+++ b/core/modules/user/src/Entity/User.php
@@ -7,6 +7,7 @@
+use Drupal\Core\Language\Language;

This is not needed.

I think we should add some tests for this and profile the patch.

There is no functional change here, it results in exactly the same behavior, just in a directer way, so not sure what you want to test?

I agree and it is pretty clear this saves performance - though it would be nice to see how much.

I thought about requiring a unit test here. The best I could come with is:

<?php

namespace Drupal\Tests\user\Unit\Entity;

use Drupal\Core\DependencyInjection\ContainerBuilder;
use Drupal\Core\Entity\EntityManager;
use Drupal\Core\Entity\EntityType;
use Drupal\Core\Language\LanguageInterface;
use Drupal\Tests\UnitTestCase;
use Drupal\user\Entity\User;


/**
 * @coversDefaultClass \Drupal\user\Entity\User
 * @group user
 */
class UserTest extends UnitTestCase {

  /**
   * @covers ::getAnonymousUser
   */
  public function testGetAnonymousUser() {
    $entity_type = $this->prophesize(EntityType::class);
    $entity_type->getClass()->willReturn(TestUser::class);
    $entity_type->id()->willReturn('user');
    $entity_manager = $this->prophesize(EntityManager::class);
    $entity_manager->getDefinition('user')->willReturn($entity_type->reveal());
    $container = new ContainerBuilder();
    $container->set('entity.manager', $entity_manager->reveal());
    \Drupal::setContainer($container);

    $anonymous = TestUser::getAnonymousUser();
    $this->assertEquals($anonymous->getValues()['langcode'], [LanguageInterface::LANGCODE_DEFAULT => LanguageInterface::LANGCODE_NOT_SPECIFIED]);
  }

}

/**
 * A test user entity to allow testing of the initialised values.
 */
class TestUser extends User {

  public function __construct(array $values, $entity_type) {
    $this->values = $values;
  }

  public function getValues() {
    return $this->values;
  }

  public function __clone() {
    // Don't do \Drupal\user\Entity\User::__clone().
  }
}

I think this might be a bit heavy on testing implementation and not behaviour.

On php 5.6 on a page with 1 anonymous comment I see very small improvements...

These improvements will grow with more anonymous comments therefore I'm going to commit this to 8.3.x and set to patch to be ported for 8.2.x. I've credit everyone who did any performance profiling on the issue.

Committed 05705fc and pushed to 8.3.x. Thanks!