…ss against unique entity constraint (wkania)This PR was merged into the 7.1 branch.Discussion----------[DoctrineBridge][Validator] Allow validating every class against unique entity constraint| Q             | A| ------------- | ---| Branch?       | 7.x <!-- see below -->| Bug fix?      | no| New feature?  | yes <!-- pleasedate src/**/CHANGELOG.md files -->| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->| Tickets       |Fix#22592| License       | MIT| Doc PR        |symfony/symfony-docs#14458 <!-- required for new features -->Yet another try to allow validating every class against unique entity constraint.Based on the knowledge from issue#22592 and pull request#24974.This constraint doesn’t provide any protection against race conditions, which is enough in most cases. You can always try-catch flush method. Let's not talk about this problem.Current state:- can be applied only to an entity,- support entity inheritance,- can validate unique combinations of multiple fields,- meaningful errors related to entities,- is valid during an update, when the only matched entity is the same as the entity being validatedNew state:- preserve the current state,- all old tests pass (no changes in them),- no breaking changes,- can be applied to any class (like DTO),- can map object fields to entity fields (optional),- when the object update some entity, there is an option to provide the identifier field names to match that entity (optional)Examples:1. DTO adds a new entity.```namespace App\Message;use Symfony\Bridge\Doctrine\Validator\Constraints\UniqueEntity;/** * `@UniqueEntity`(fields={"name"}, entityClass="App\Entity\User") */class HireAnEmployee{    public $name;    public function __construct($name)    {        $this->name = $name;    }}```2. DTO adds a new entity, but the name of the field in the entity is different.```namespace App\Message;use Symfony\Bridge\Doctrine\Validator\Constraints\UniqueEntity;/** * `@UniqueEntity`(fields={"name": "username"}, entityClass="App\Entity\User") */class HireAnEmployee{    public $name;    public function __construct($name)    {        $this->name = $name;    }}```3. DTO updates an entity.```namespace App\Message;use Symfony\Bridge\Doctrine\Validator\Constraints\UniqueEntity;/** * `@UniqueEntity`(fields={"name"}, entityClass="App\Entity\User", identifierFieldNames={"uid": "id"}) */class UpdateEmployeeProfile{    public $uid;    public $name;    public function __construct($uid, $name)    {        $this->uid = $uid;        $this->name = $name;    }}```Commits-------adb9afa [DoctrineBridge][Validator] Allow validating every class against unique entity constraint

…ject (HypeMC)This PR was merged into the 7.1 branch.Discussion----------[DoctrineBridge] Fix `UniqueEntityValidator` with proxy object| Q             | A| ------------- | ---| Branch?       | 7.1| Bug fix?      | yes| New feature?  | no| Deprecations? | no| Issues        |Fix#57075| License       | MITBefore#38662, `$fieldValue = $class->reflFields[$fieldName]->getValue($entity);` was used to get the value of a property, so it makes sense to keep using it when the object is an entity.Commits-------99f279b [DoctrineBridge] Fix `UniqueEntityValidator` with proxy object