Merge branch '5.4' into 6.0

* 5.4:
  Avoid duplicated session listener registration in tests
  [HttpFoundation] fix SessionHandlerFactory using connections
  [gha] swap the php versions we use in jobs
  [DoctrineBridge] fix calling get_class on non-object
  Update PR template
  ResponseListener needs only 2 parameters
  [Lock] create lock table if it does not exist
  [HttpClient] Fix handling error info in MockResponse
  [SecurityBundle] Fix invalid reference with `always_authenticate_before_granting`
  Bump Symfony version to 5.4.1
  Update VERSION for 5.4.0
  Update CHANGELOG for 5.4.0

Author: nicolas-grekas

Tests/Validator/Constraints/UniqueEntityValidatorTest.php

@@ -37,6 +37,7 @@
 use Symfony\Bridge\Doctrine\Validator\Constraints\UniqueEntity;
 use Symfony\Bridge\Doctrine\Validator\Constraints\UniqueEntityValidator;
 use Symfony\Component\Validator\Exception\ConstraintDefinitionException;
+use Symfony\Component\Validator\Exception\UnexpectedValueException;
 use Symfony\Component\Validator\Test\ConstraintValidatorTestCase;
 
 /**
@@ -849,6 +850,32 @@ public function testValidateUniquenessWithEmptyIterator($entity, $result)
         $this->assertNoViolation();
     }
 
+    public function testValueMustBeObject()
+    {
+        $constraint = new UniqueEntity([
+            'message' => 'myMessage',
+            'fields' => ['name'],
+            'em' => self::EM_NAME,
+        ]);
+
+        $this->expectException(UnexpectedValueException::class);
+
+        $this->validator->validate('foo', $constraint);
+    }
+
+    public function testValueCanBeNull()
+    {
+        $constraint = new UniqueEntity([
+            'message' => 'myMessage',
+            'fields' => ['name'],
+            'em' => self::EM_NAME,
+        ]);
+
+        $this->validator->validate(null, $constraint);
+
+        $this->assertNoViolation();
+    }
+
     public function resultWithEmptyIterator(): array
     {
         $entity = new SingleIntIdEntity(1, 'foo');

Validator/Constraints/UniqueEntityValidator.php

@@ -18,6 +18,7 @@
 use Symfony\Component\Validator\ConstraintValidator;
 use Symfony\Component\Validator\Exception\ConstraintDefinitionException;
 use Symfony\Component\Validator\Exception\UnexpectedTypeException;
+use Symfony\Component\Validator\Exception\UnexpectedValueException;
 
 /**
  * Unique Entity Validator checks if one or a set of fields contain unique values.
@@ -63,6 +64,10 @@ public function validate(mixed $entity, Constraint $constraint)
             return;
         }
 
+        if (!\is_object($entity)) {
+            throw new UnexpectedValueException($entity, 'object');
+        }
+
         if ($constraint->em) {
             $em = $this->registry->getManager($constraint->em);