From 68cf0cfd6b33b6c3c48026c41da18286edbca43f Mon Sep 17 00:00:00 2001
From: Oskar Stark <oskarstark@googlemail.com>
Date: Thu, 1 Aug 2019 08:14:09 +0200
Subject: [PATCH] [Yaml] Dump null as tilde

---
 components/yaml.rst | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/components/yaml.rst b/components/yaml.rst
index c3f355ab1da..bc6a4bc3634 100644
--- a/components/yaml.rst
+++ b/components/yaml.rst
@@ -375,6 +375,23 @@ objects, they are automatically transformed into YAML tags::
     $dumped = Yaml::dump($data);
     // $dumped = '!my_tag { foo: bar }'
 
+Dumping null
+~~~~~~~~~~~~
+
+``null`` values will be represented with ``null`` by default::
+
+    $dumped = Yaml::dump(array('foo' => null));
+    // foo: null
+
+You can represent them with ``~`` by using the ``DUMP_NULL_AS_TILDE`` flag::
+
+    $dumped = Yaml::dump(array('foo' => null), 2, 4, Yaml::DUMP_NULL_AS_TILDE);
+    // foo: ~
+
+.. versionadded:: 4.4
+
+    The flag to dump ``null`` as ``~`` was introduced in Symfony 4.4.
+
 Syntax Validation
 ~~~~~~~~~~~~~~~~~