From cf357e97ffa2d9ceaf19b97846099116348f015f Mon Sep 17 00:00:00 2001
From: Mikhail Alferov <malferov@gmail.com>
Date: Thu, 8 May 2025 07:28:31 +0300
Subject: [PATCH 1/5] serialize.xml Show how the method works

---
 .../datetime/datetimeinterface/serialize.xml  | 22 ++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/reference/datetime/datetimeinterface/serialize.xml b/reference/datetime/datetimeinterface/serialize.xml
index 5615dca18157..c6a322b8955a 100644
--- a/reference/datetime/datetimeinterface/serialize.xml
+++ b/reference/datetime/datetimeinterface/serialize.xml
@@ -43,19 +43,35 @@
  <refsect1 role="examples">
   &reftitle.examples;
   <example>
-   <title><function>DateTime::serialize</function> example</title>
+   <title><methodname>DateTime::__serialize</methodname> example</title>
    <programlisting role="php">
 <![CDATA[
 <?php
-$date = new DateTime('2025-03-27');
+
+class CustomDateTimeImmutable extends DateTimeImmutable
+{
+    #[\Override]
+    public function __serialize(): array
+    {
+        return [
+            'date' => $this->format(DateTimeInterface::W3C),
+            'timestamp' => $this->getTimestamp(),
+            'timezone' => $this->getTimeZone()->getName(),
+            'to' => 'Drink a cup of coffee',
+        ];
+    }
+}
+
+$date = new CustomDateTimeImmutable('2025-03-27');
 var_dump(serialize($date));
+
 ?>
 ]]>
    </programlisting>
    &examples.outputs;
    <screen>
 <![CDATA[
-string(114) "O:8:"DateTime":3:{s:4:"date";s:26:"2025-03-27 00:00:00.000000";s:13:"timezone_type";i:3;s:8:"timezone";s:3:"UTC";}"
+string(171) "O:23:"CustomDateTimeImmutable":4:{s:4:"date";s:25:"2025-03-27T00:00:00+00:00";s:9:"timestamp";i:1743033600;s:8:"timezone";s:3:"UTC";s:2:"to";s:21:"Drink a cup of coffee";}"
 ]]>
    </screen>
   </example>

From e9148ffe9fa213c744e2cff7425a31cfb330e743 Mon Sep 17 00:00:00 2001
From: Mikhail Alferov <malferov@gmail.com>
Date: Thu, 8 May 2025 08:21:39 +0300
Subject: [PATCH 2/5] serialize.xml Add an Error warning if __unserialize() is
 missing

---
 reference/datetime/datetimeinterface/serialize.xml | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/reference/datetime/datetimeinterface/serialize.xml b/reference/datetime/datetimeinterface/serialize.xml
index c6a322b8955a..0a6934b9b630 100644
--- a/reference/datetime/datetimeinterface/serialize.xml
+++ b/reference/datetime/datetimeinterface/serialize.xml
@@ -77,6 +77,17 @@ string(171) "O:23:"CustomDateTimeImmutable":4:{s:4:"date";s:25:"2025-03-27T00:00
   </example>
  </refsect1>
 
+ <refsect1 role="notes">
+  &reftitle.notes;
+  <warning>
+   <para>
+    An <classname>Error</classname> is thrown when attempting to unserialize a custom
+    <classname>DateTime</classname> object if the <link linkend="object.serialize">__serialize()</link> is
+    defined but the <link linkend="object.unserialize">__unserialize()</link> is missing.
+   </para>
+  </warning>
+ </refsect1>
+
  <refsect1 role="seealso">
   &reftitle.seealso;
   <simplelist>

From 04de2dfc32eba621c8ea9631955c136a3d820c20 Mon Sep 17 00:00:00 2001
From: Mikhail Alferov <malferov@gmail.com>
Date: Thu, 8 May 2025 08:23:53 +0300
Subject: [PATCH 3/5] unserialize.xml Show how the method works

---
 .../datetimeinterface/unserialize.xml         | 20 ++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/reference/datetime/datetimeinterface/unserialize.xml b/reference/datetime/datetimeinterface/unserialize.xml
index f60f36c4bb9e..2aea9acf4a60 100644
--- a/reference/datetime/datetimeinterface/unserialize.xml
+++ b/reference/datetime/datetimeinterface/unserialize.xml
@@ -51,12 +51,26 @@
  <refsect1 role="examples">
   &reftitle.examples;
   <example>
-   <title><function>DateTime::unserialize</function> example</title>
+   <title><methodname>DateTime::__unserialize</methodname> example</title>
    <programlisting role="php">
 <![CDATA[
 <?php
-$serializedDate = 'O:8:"DateTime":3:{s:4:"date";s:26:"2025-03-27 00:00:00.000000";s:13:"timezone_type";i:3;s:8:"timezone";s:3:"UTC";}';
-var_dump(unserialize($serializedDate));
+
+class CustomDateTimeImmutable extends DateTimeImmutable
+{
+    #[\Override]
+    public function __unserialize(array $data): void
+    {
+        echo "Time to `{$data['to']}`:\n\n";
+
+        $this->__construct($data['date'], new DateTimeZone($data['timezone']));
+    }
+}
+
+$serializedData = 'O:23:"CustomDateTimeImmutable":4:{s:4:"date";s:25:"2025-03-27T00:00:00+00:00";s:9:"timestamp";i:1743033600;s:8:"timezone";s:3:"UTC";s:2:"to";s:21:"Drink a cup of coffee";}';
+
+var_dump(unserialize($serializedData));
+
 ?>
 ]]>
    </programlisting>

From b9af72fa11aa94cafeca56e79bb430bf9234814e Mon Sep 17 00:00:00 2001
From: Mikhail Alferov <malferov@gmail.com>
Date: Thu, 8 May 2025 08:30:50 +0300
Subject: [PATCH 4/5] unserialize.xml No value is returned

---
 reference/datetime/datetimeinterface/unserialize.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/reference/datetime/datetimeinterface/unserialize.xml b/reference/datetime/datetimeinterface/unserialize.xml
index 2aea9acf4a60..1e419cd63f0b 100644
--- a/reference/datetime/datetimeinterface/unserialize.xml
+++ b/reference/datetime/datetimeinterface/unserialize.xml
@@ -44,7 +44,7 @@
  <refsect1 role="returnvalues">
   &reftitle.returnvalues;
   <para>
-   The <classname>DateTime</classname> object.
+   &return.void;
   </para>
  </refsect1>
 

From 46396388653c9d0295282d68580a8c9f560d077e Mon Sep 17 00:00:00 2001
From: Mikhail Alferov <malferov@gmail.com>
Date: Thu, 8 May 2025 08:38:14 +0300
Subject: [PATCH 5/5] unserialize.xml Add an Error warning

---
 reference/datetime/datetimeinterface/unserialize.xml | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/reference/datetime/datetimeinterface/unserialize.xml b/reference/datetime/datetimeinterface/unserialize.xml
index 1e419cd63f0b..d33005a44b91 100644
--- a/reference/datetime/datetimeinterface/unserialize.xml
+++ b/reference/datetime/datetimeinterface/unserialize.xml
@@ -90,6 +90,17 @@ object(DateTime)#1 (3) {
   </example>
  </refsect1>
 
+ <refsect1 role="notes">
+  &reftitle.notes;
+  <warning>
+   <para>
+    An <classname>Error</classname> is thrown when attempting to unserialize a custom
+    <classname>DateTime</classname> object if the <link linkend="object.serialize">__serialize()</link> is
+    defined but the <link linkend="object.unserialize">__unserialize()</link> is missing.
+   </para>
+  </warning>
+ </refsect1>
+
  <refsect1 role="seealso">
   &reftitle.seealso;
   <simplelist>