Add doc for UniqueEntity new feature

VincentLanglet · VincentLanglet · commit c28682c1b37f · 2023-05-22T16:42:26.000+02:00
diff --git a/reference/constraints/UniqueEntity.rst b/reference/constraints/UniqueEntity.rst
@@ -251,13 +251,41 @@ each with a single field.
 ``ignoreNull``
 ~~~~~~~~~~~~~~
 
-**type**: ``boolean`` **default**: ``true``
+**type**: ``boolean`` | ``array`` | ``string`` **default**: ``true``
 
 If this option is set to ``true``, then the constraint will allow multiple
 entities to have a ``null`` value for a field without failing validation.
 If set to ``false``, only one ``null`` value is allowed - if a second entity
 also has a ``null`` value, validation would fail.
 
+As of Symfony 6.3, the ``UniqueEntity`` constraint allows you to ignore null
+values on specific fields when checking for uniqueness. This feature can be
+helpful when you want to validate the uniqueness of a combination of fields,
+but want to exclude combinations where one or more of the fields are null.
+
+.. code-block:: php
+
+    use Symfony\Bridge\Doctrine\Validator\Constraints\UniqueEntity;
+
+    #[UniqueEntity(
+         fields: ['name', 'email'],
+         ignoreNull: 'name',
+    )]
+
+In the example above, null values for the "name" field will be ignored
+when checking for uniqueness.
+
+Similarly, you can ignore null values for multiple fields:
+
+.. code-block:: php
+
+    #[UniqueEntity(
+         fields: ['name', 'country', 'email'],
+         ignoreNull: ['name', 'country'],
+    )]
+
+In this case, null values for both the "name" and "country" fields will be ignored.
+
 ``message``
 ~~~~~~~~~~~
 
