Recommend SEQUENCE until doctrine/dbal 4 is released

Using IDENTITY with doctrine/dbal 3 results in SERIAL, which is not
recommended.

UPGRADE.md

@@ -16,23 +16,22 @@ Because of that, it is now deprecated to rely on the historical defaults when
 they differ from what we recommend now.
 
 Instead, you should pick a strategy for each database platform you use, and it
-will be used when using `AUTO`. As of now, only PostgreSQL is affected by this.
-It is recommended that PostgreSQL user configure their new applications to use
-`IDENTITY`:
+will be used when using `AUTO`. As of now, no platform is affected by this, but
+PostgreSQL will be when `doctrine/dbal` 4 is released.
+
+It is recommended that PostgreSQL users configure their existing and new
+applications to use `SEQUENCE` until that happens:
 
 ```php
 use Doctrine\DBAL\Platforms\PostgreSQLPlatform;
 use Doctrine\ORM\Configuration;
 
 assert($configuration instanceof Configuration);
 $configuration->setIdentityGenerationPreferences([
- PostgreSQLPlatform::CLASS => ClassMetadata::GENERATOR_TYPE_IDENTITY,
+ PostgreSQLPlatform::CLASS => ClassMetadata::GENERATOR_TYPE_SEQUENCE,
 ]);
 ```
 
-If migrating an existing application is too costly, the deprecation can be
-addressed by configuring `SEQUENCE` as the default strategy.
-
 ## Deprecate `EntityManagerInterface::getPartialReference()`
 
 This method does not have a replacement and will be removed in 3.0.

docs/en/reference/basic-mapping.rst

@@ -427,20 +427,6 @@ defaults to the identifier generation mechanism your current database
 vendor preferred at the time that strategy was introduced:
 ``AUTO_INCREMENT`` with MySQL, sequences with PostgreSQL and Oracle and
 so on.
-We now recommend using ``IDENTITY`` for PostgreSQL, and you can achieve
-that while still using the ``AUTO`` strategy, by configuring what it
-defaults to.
-
-.. code-block:: php
-
- <?php
- use Doctrine\DBAL\Platforms\PostgreSQLPlatform;
- use Doctrine\ORM\Configuration;
-
- $config = new Configuration();
- $config->setIdentityGenerationPreferences([
- PostgreSQLPlatform::class => ClassMetadata::GENERATOR_TYPE_IDENTITY,
- ]);
 
 .. _identifier-generation-strategies:
 

lib/Doctrine/ORM/Mapping/ClassMetadataFactory.php

@@ -87,11 +87,11 @@ class ClassMetadataFactory extends AbstractClassMetadataFactory
 
  private const RECOMMENDED_STRATEGY = [
  'Doctrine\DBAL\Platforms\MySqlPlatform' => 'IDENTITY',
- 'Doctrine\DBAL\Platforms\PostgreSqlPlatform' => 'IDENTITY',
+ 'Doctrine\DBAL\Platforms\PostgreSqlPlatform' => 'SEQUENCE',
  Platforms\DB2Platform::class => 'IDENTITY',
  Platforms\MySQLPlatform::class => 'IDENTITY',
  Platforms\OraclePlatform::class => 'SEQUENCE',
- Platforms\PostgreSQLPlatform::class => 'IDENTITY',
+ Platforms\PostgreSQLPlatform::class => 'SEQUENCE',
  Platforms\SQLServerPlatform::class => 'IDENTITY',
  Platforms\SqlitePlatform::class => 'IDENTITY',
  ];
@@ -657,7 +657,7 @@ private function completeIdGeneratorMapping(ClassMetadataInfo $class): void
  'https://github.com/doctrine/orm/issues/8850',
  <<<'DEPRECATION'
 Context: Loading metadata for class %s
-Problem: Using the IDENTITY generator strategy with platform "%s" is deprecated and will not be possible in Doctrine ORM 3.0.
+Problem: Using identity columns emulated with a sequence is deprecated and will not be possible in Doctrine ORM 3.0.
 Solution: Use the SEQUENCE generator strategy instead.
 DEPRECATION
  ,

tests/Doctrine/Tests/ORM/Mapping/ClassMetadataFactoryTest.php

@@ -10,7 +10,6 @@
 use Doctrine\DBAL\Driver;
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Platforms\OraclePlatform;
-use Doctrine\DBAL\Platforms\PostgreSQLPlatform;
 use Doctrine\Deprecations\PHPUnit\VerifyDeprecations;
 use Doctrine\ORM\Configuration;
 use Doctrine\ORM\EntityManagerInterface;
@@ -170,32 +169,6 @@ private function setUpCmfForPlatform(AbstractPlatform $platform, array $preferen
  return $cmf;
  }
 
- public function testRelyingOnLegacyIdGenerationDefaultsIsDeprecatedIfItResultsInASuboptimalDefault(): void
- {
- $cm = $this->createValidClassMetadata();
- $cm->setIdGeneratorType(ClassMetadata::GENERATOR_TYPE_AUTO);
-
- $cmf = $this->setUpCmfForPlatform(new PostgreSQLPlatform());
- $cmf->setMetadataForClass($cm->name, $cm);
-
- $this->expectDeprecationWithIdentifier('https://github.com/doctrine/orm/issues/8893');
- $cmf->getMetadataFor($cm->name);
- }
-
- public function testSpecifyingIdGenerationStrategyThroughConfigurationFixesTheDeprecation(): void
- {
- $cm = $this->createValidClassMetadata();
- $cm->setIdGeneratorType(ClassMetadata::GENERATOR_TYPE_AUTO);
-
- $cmf = $this->setUpCmfForPlatform(new PostgreSQLPlatform(), [
- PostgreSQLPlatform::class => ClassMetadata::GENERATOR_TYPE_IDENTITY,
- ]);
- $cmf->setMetadataForClass($cm->name, $cm);
-
- $this->expectNoDeprecationWithIdentifier('https://github.com/doctrine/orm/issues/8893');
- $cmf->getMetadataFor($cm->name);
- }
-
  public function testRelyingOnLegacyIdGenerationDefaultsIsOKIfItResultsInTheCurrentlyRecommendedStrategyBeingUsed(): void
  {
  $cm = $this->createValidClassMetadata();