From c5b0a1127f3ef63750520f06548eed4e7d27a6cc Mon Sep 17 00:00:00 2001
From: Dhrupo Nil <dhrupo@gmail.com>
Date: Fri, 30 Oct 2026 13:46:19 +0600
Subject: [PATCH] Silence PHP 8.6 tentative return type deprecations in
 DateTimeImmutable

PHP 8.6 gives DateTimeImmutable::add(), sub(), modify(), setDate(),
setISODate(), setTime(), setTimestamp(), setTimezone() and
createFromInterface() a tentative static return type. Safe's overrides
return self, so declaring the class emits nine deprecation notices.

Mark them #[\ReturnTypeWillChange], as createFromMutable() and
__set_state() already are.
---
 lib/DateTimeImmutable.php       |  9 +++++++++
 tests/DateTimeImmutableTest.php | 24 ++++++++++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/lib/DateTimeImmutable.php b/lib/DateTimeImmutable.php
index 99f74101..7cb973f9 100644
--- a/lib/DateTimeImmutable.php
+++ b/lib/DateTimeImmutable.php
@@ -96,6 +96,7 @@ public function diff($datetime2, $absolute = false): \DateInterval
      * @return DateTimeImmutable
      * @throws DatetimeException
      */
+    #[\ReturnTypeWillChange]
     public function modify($modify): self
     {
         /** @var \DateTimeImmutable|false $result */
@@ -113,6 +114,7 @@ public function modify($modify): self
      * @return DateTimeImmutable
      * @throws DatetimeException
      */
+    #[\ReturnTypeWillChange]
     public function setDate($year, $month, $day): self
     {
         /** @var \DateTimeImmutable|false $result */
@@ -130,6 +132,7 @@ public function setDate($year, $month, $day): self
      * @return DateTimeImmutable
      * @throws DatetimeException
      */
+    #[\ReturnTypeWillChange]
     public function setISODate($year, $week, $day = 1): self
     {
         /** @var \DateTimeImmutable|false $result */
@@ -148,6 +151,7 @@ public function setISODate($year, $week, $day = 1): self
      * @return DateTimeImmutable
      * @throws DatetimeException
      */
+    #[\ReturnTypeWillChange]
     public function setTime($hour, $minute, $second = 0, $microseconds = 0): self
     {
         /** @var \DateTimeImmutable|false $result */
@@ -163,6 +167,7 @@ public function setTime($hour, $minute, $second = 0, $microseconds = 0): self
      * @return DateTimeImmutable
      * @throws DatetimeException
      */
+    #[\ReturnTypeWillChange]
     public function setTimestamp($unixtimestamp): self
     {
         /** @var \DateTimeImmutable|false $result */
@@ -178,6 +183,7 @@ public function setTimestamp($unixtimestamp): self
      * @return DateTimeImmutable
      * @throws DatetimeException
      */
+    #[\ReturnTypeWillChange]
     public function setTimezone($timezone): self
     {
         /** @var \DateTimeImmutable|false $result */
@@ -193,6 +199,7 @@ public function setTimezone($timezone): self
      * @return DateTimeImmutable
      * @throws DatetimeException
      */
+    #[\ReturnTypeWillChange]
     public function sub($interval): self
     {
         /** @var \DateTimeImmutable|false $result */
@@ -223,6 +230,7 @@ public function getOffset(): int
      * @param \DateInterval $interval
      * @return DateTimeImmutable
      */
+    #[\ReturnTypeWillChange]
     public function add($interval): self
     {
         return self::createFromRegular($this->innerDateTime->add($interval));
@@ -243,6 +251,7 @@ public static function createFromMutable($dateTime): self
     /**
      * @return DateTimeImmutable
      */
+    #[\ReturnTypeWillChange]
     public static function createFromInterface(\DateTimeInterface $object): self
     {
         if ($object instanceof \DateTime) {
diff --git a/tests/DateTimeImmutableTest.php b/tests/DateTimeImmutableTest.php
index 9a0a55e1..1adbe2ab 100644
--- a/tests/DateTimeImmutableTest.php
+++ b/tests/DateTimeImmutableTest.php
@@ -6,6 +6,30 @@
 
 final class DateTimeImmutableTest extends TestCase
 {
+    /**
+     * PHP 8.6 adds tentative static return types to DateTimeImmutable, so an
+     * incompatible override is reported once, when the class is declared.
+     *
+     * @runInSeparateProcess
+     */
+    public function testDeclaringTheClassTriggersNoDeprecation(): void
+    {
+        $deprecations = [];
+        set_error_handler(static function (int $errno, string $errstr) use (&$deprecations): bool {
+            $deprecations[] = $errstr;
+
+            return true;
+        }, E_DEPRECATED);
+
+        try {
+            self::assertTrue(class_exists(\Safe\DateTimeImmutable::class));
+        } finally {
+            restore_error_handler();
+        }
+
+        self::assertSame([], $deprecations);
+    }
+
     public function testCreateFromMutable(): void
     {
         $unsafeDate = new \DateTime('2021-10-16T12:30:16+00:00');