diff --git a/src/Symfony/Bridge/Monolog/Tests/Handler/ChromePhpHandlerTest.php b/src/Symfony/Bridge/Monolog/Tests/Handler/ChromePhpHandlerTest.php
index 1d237059619f7..a83ef9eb6cbd5 100644
--- a/src/Symfony/Bridge/Monolog/Tests/Handler/ChromePhpHandlerTest.php
+++ b/src/Symfony/Bridge/Monolog/Tests/Handler/ChromePhpHandlerTest.php
@@ -22,15 +22,19 @@ class ChromePhpHandlerTest extends TestCase
 {
     public function testOnKernelResponseShouldNotTriggerDeprecation()
     {
-        $this->expectNotToPerformAssertions();
-
         $request = Request::create('/');
         $request->headers->remove('User-Agent');
 
         $response = new Response('foo');
         $event = new ResponseEvent($this->createMock(HttpKernelInterface::class), $request, HttpKernelInterface::MAIN_REQUEST, $response);
 
+        $error = null;
+        set_error_handler(function ($type, $message) use (&$error) { $error = $message; }, \E_DEPRECATED);
+
         $listener = new ChromePhpHandler();
         $listener->onKernelResponse($event);
+        restore_error_handler();
+
+        $this->assertNull($error);
     }
 }
diff --git a/src/Symfony/Component/Validator/CHANGELOG.md b/src/Symfony/Component/Validator/CHANGELOG.md
index 5e480139e8690..b5e79134e98a9 100644
--- a/src/Symfony/Component/Validator/CHANGELOG.md
+++ b/src/Symfony/Component/Validator/CHANGELOG.md
@@ -18,6 +18,7 @@ CHANGELOG
  * Add the `Week` constraint
  * Add `CompoundConstraintTestCase` to ease testing Compound Constraints
  * Add context variable to `WhenValidator`
+ * Add `format` parameter to `DateTime` constraint violation message
 
 7.1
 ---
diff --git a/src/Symfony/Component/Validator/Constraints/DateTimeValidator.php b/src/Symfony/Component/Validator/Constraints/DateTimeValidator.php
index 9784a57976d29..f5765cbf6e119 100644
--- a/src/Symfony/Component/Validator/Constraints/DateTimeValidator.php
+++ b/src/Symfony/Component/Validator/Constraints/DateTimeValidator.php
@@ -44,6 +44,7 @@ public function validate(mixed $value, Constraint $constraint): void
         if (0 < $errors['error_count']) {
             $this->context->buildViolation($constraint->message)
                 ->setParameter('{{ value }}', $this->formatValue($value))
+                ->setParameter('{{ format }}', $this->formatValue($constraint->format))
                 ->setCode(DateTime::INVALID_FORMAT_ERROR)
                 ->addViolation();
 
@@ -58,16 +59,19 @@ public function validate(mixed $value, Constraint $constraint): void
             if ('The parsed date was invalid' === $warning) {
                 $this->context->buildViolation($constraint->message)
                     ->setParameter('{{ value }}', $this->formatValue($value))
+                    ->setParameter('{{ format }}', $this->formatValue($constraint->format))
                     ->setCode(DateTime::INVALID_DATE_ERROR)
                     ->addViolation();
             } elseif ('The parsed time was invalid' === $warning) {
                 $this->context->buildViolation($constraint->message)
                     ->setParameter('{{ value }}', $this->formatValue($value))
+                    ->setParameter('{{ format }}', $this->formatValue($constraint->format))
                     ->setCode(DateTime::INVALID_TIME_ERROR)
                     ->addViolation();
             } else {
                 $this->context->buildViolation($constraint->message)
                     ->setParameter('{{ value }}', $this->formatValue($value))
+                    ->setParameter('{{ format }}', $this->formatValue($constraint->format))
                     ->setCode(DateTime::INVALID_FORMAT_ERROR)
                     ->addViolation();
             }
diff --git a/src/Symfony/Component/Validator/Tests/Constraints/DateTimeValidatorTest.php b/src/Symfony/Component/Validator/Tests/Constraints/DateTimeValidatorTest.php
index 8da07c424f40e..42519ffd4d6d6 100644
--- a/src/Symfony/Component/Validator/Tests/Constraints/DateTimeValidatorTest.php
+++ b/src/Symfony/Component/Validator/Tests/Constraints/DateTimeValidatorTest.php
@@ -53,6 +53,7 @@ public function testDateTimeWithDefaultFormat()
 
         $this->buildViolation('This value is not a valid datetime.')
             ->setParameter('{{ value }}', '"1995-03-24"')
+            ->setParameter('{{ format }}', '"Y-m-d H:i:s"')
             ->setCode(DateTime::INVALID_FORMAT_ERROR)
             ->assertRaised();
     }
@@ -96,6 +97,7 @@ public function testInvalidDateTimes($format, $dateTime, $code)
 
         $this->buildViolation('myMessage')
             ->setParameter('{{ value }}', '"'.$dateTime.'"')
+            ->setParameter('{{ format }}', '"'.$format.'"')
             ->setCode($code)
             ->assertRaised();
     }
@@ -124,6 +126,7 @@ public function testInvalidDateTimeNamed()
 
         $this->buildViolation('myMessage')
             ->setParameter('{{ value }}', '"2010-01-01 00:00:00"')
+            ->setParameter('{{ format }}', '"Y-m-d"')
             ->setCode(DateTime::INVALID_FORMAT_ERROR)
             ->assertRaised();
     }