From b1e160c41e62aec2c496092505763e09e0bc8f15 Mon Sep 17 00:00:00 2001
From: Pierre du Plessis <pierre@pcservice.co.za>
Date: Mon, 5 Aug 2019 12:19:56 +0200
Subject: [PATCH] Support DateTimeInterface in IntlDateFormatter::format

---
 .../Component/Intl/DateFormatter/IntlDateFormatter.php   | 6 +++---
 .../DateFormatter/AbstractIntlDateFormatterTest.php      | 9 +++++++++
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/src/Symfony/Component/Intl/DateFormatter/IntlDateFormatter.php b/src/Symfony/Component/Intl/DateFormatter/IntlDateFormatter.php
index 0f19310f22bf..197a2e3db06f 100644
--- a/src/Symfony/Component/Intl/DateFormatter/IntlDateFormatter.php
+++ b/src/Symfony/Component/Intl/DateFormatter/IntlDateFormatter.php
@@ -176,7 +176,7 @@ public static function create($locale, $datetype, $timetype, $timezone = null, $
     /**
      * Format the date/time value (timestamp) as a string.
      *
-     * @param int|\DateTime $timestamp The timestamp to format
+     * @param int|\DateTimeInterface $timestamp The timestamp to format
      *
      * @return string|bool The formatted value or false if formatting failed
      *
@@ -195,7 +195,7 @@ public function format($timestamp)
 
         // behave like the intl extension
         $argumentError = null;
-        if (!\is_int($timestamp) && !$timestamp instanceof \DateTime) {
+        if (!\is_int($timestamp) && !$timestamp instanceof \DateTimeInterface) {
             $argumentError = sprintf('datefmt_format: string \'%s\' is not numeric, which would be required for it to be a valid date', $timestamp);
         }
 
@@ -207,7 +207,7 @@ public function format($timestamp)
             return false;
         }
 
-        if ($timestamp instanceof \DateTime) {
+        if ($timestamp instanceof \DateTimeInterface) {
             $timestamp = $timestamp->getTimestamp();
         }
 
diff --git a/src/Symfony/Component/Intl/Tests/DateFormatter/AbstractIntlDateFormatterTest.php b/src/Symfony/Component/Intl/Tests/DateFormatter/AbstractIntlDateFormatterTest.php
index e472000974a6..682380bf5415 100644
--- a/src/Symfony/Component/Intl/Tests/DateFormatter/AbstractIntlDateFormatterTest.php
+++ b/src/Symfony/Component/Intl/Tests/DateFormatter/AbstractIntlDateFormatterTest.php
@@ -76,6 +76,7 @@ public function testFormat($pattern, $timestamp, $expected)
     public function formatProvider()
     {
         $dateTime = new \DateTime('@0');
+        $dateTimeImmutable = new \DateTimeImmutable('@0');
 
         $formatData = [
             /* general */
@@ -250,6 +251,12 @@ public function formatProvider()
         $formatData[] = ['h:mm a', $dateTime, '12:00 AM'];
         $formatData[] = ['yyyyy.MMMM.dd hh:mm aaa', $dateTime, '01970.January.01 12:00 AM'];
 
+        /* general, DateTimeImmutable */
+        $formatData[] = ['y-M-d', $dateTimeImmutable, '1970-1-1'];
+        $formatData[] = ["EEE, MMM d, ''yy", $dateTimeImmutable, "Thu, Jan 1, '70"];
+        $formatData[] = ['h:mm a', $dateTimeImmutable, '12:00 AM'];
+        $formatData[] = ['yyyyy.MMMM.dd hh:mm aaa', $dateTimeImmutable, '01970.January.01 12:00 AM'];
+
         if (IcuVersion::compare(Intl::getIcuVersion(), '59.1', '>=', 1)) {
             // Before ICU 59.1 GMT was used instead of UTC
             $formatData[] = ["yyyy.MM.dd 'at' HH:mm:ss zzz", 0, '1970.01.01 at 00:00:00 UTC'];
@@ -272,6 +279,8 @@ public function testFormatUtcAndGmtAreSplit()
 
         $this->assertSame('1970.01.01 at 00:00:00 GMT', $gmtFormatter->format(new \DateTime('@0')));
         $this->assertSame('1970.01.01 at 00:00:00 UTC', $utcFormatter->format(new \DateTime('@0')));
+        $this->assertSame('1970.01.01 at 00:00:00 GMT', $gmtFormatter->format(new \DateTimeImmutable('@0')));
+        $this->assertSame('1970.01.01 at 00:00:00 UTC', $utcFormatter->format(new \DateTimeImmutable('@0')));
     }
 
     /**