date formatter fall back to PHP impl. to solve Y2K38 issue

formatting date and time values for years >=2038 or <=1901 is now possible also with intl extension is
installed. 32bit systems will fall back to the PHP implementation because intl uses a 32bit UNIX timestamp internally.
On a 64bit system the intl formatter is used in all cases if installed.

fixes #5577

docs/guide/output-formatter.md

@@ -51,6 +51,10 @@ echo Yii::$app->formatter->asDate('2014-01-01'); // output: 1 января 2014
 > [PHP intl extension](http://php.net/manual/en/book.intl.php) is installed or not. So to ensure your website works with the same output
 > in all environments it is recommended to install the PHP intl extension in all environments and verify that the version of the ICU library
 > is the same. See also: [Setting up your PHP environment for internationalization](tutorial-i18n.md#setup-environment).
+>
+> Note also that even if the intl extension is installed, formatting date and time values for years >=2038 or <=1901
+> on 32bit systems will fall back to the PHP implementation, which does not provide localized month and day names,
+> because intl uses a 32bit UNIX timestamp internally. On a 64bit system the intl formatter is used in all cases if installed.
 
 
 Configuring the formatter <a name="configuring-format"></a>

framework/CHANGELOG.md

@@ -4,6 +4,7 @@ Yii Framework 2 Change Log
 2.0.2 under development
 -----------------------
 
+- Bug #5577: formatting date and time values for years >=2038 or <=1901 on 32bit systems will not use intl extension but fall back to the PHP implementation (cebe)
 - Bug #6080: Oracle DB schema did not load column types correctly (wenbin1989)
 - Bug #6404: advanced application template `Alert` widget was generating duplicate IDs in case of multiple flashes (SDKiller)
 - Bug #6557: Link URLs generated by `yii\widgets\Menu` are not encoded (qiangxue)

framework/i18n/Formatter.php

@@ -35,6 +35,9 @@ use yii\helpers\Html;
  * the [PHP intl extension](http://php.net/manual/en/book.intl.php) has to be installed.
  * Most of the methods however work also if the PHP intl extension is not installed by providing
  * a fallback implementation. Without intl month and day names are in English only.
+ * Note that even if the intl extension is installed, formatting date and time values for years >=2038 or <=1901
+ * on 32bit systems will fall back to the PHP implementation because intl uses a 32bit UNIX timestamp internally.
+ * On a 64bit system the intl formatter is used in all cases if installed.
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @author Enrica Ruedin <e.ruedin@guggach.com>
@@ -543,7 +546,9 @@ class Formatter extends Component
             return $this->nullDisplay;
         }
 
-        if ($this->_intlLoaded) {
+        // intl does not work with dates >=2038 or <=1901 on 32bit machines, fall back to PHP
+        $year = $timestamp->format('Y');
+        if ($this->_intlLoaded && !(PHP_INT_SIZE == 4 && ($year <= 1901 || $year >= 2038))) {
             if (strncmp($format, 'php:', 4) === 0) {
                 $format = FormatConverter::convertDatePhpToIcu(substr($format, 4));
             }

tests/unit/framework/i18n/FormatterDateTest.php

@@ -182,9 +182,7 @@ class FormatterDateTest extends TestCase
 
     public function testIntlDateRangeLow()
     {
-        if (PHP_INT_SIZE == 4) { // 32bit systems
-            $this->markTestSkipped('intl does not support high date ranges on 32bit systems.');
-        }
+        // intl does not support high date ranges on 32bit systems, the implementation uses a fallback to PHP formatter
         $this->testDateRangeLow();
     }
 
@@ -196,13 +194,12 @@ class FormatterDateTest extends TestCase
     {
         $this->assertSame('12-08-1922', $this->formatter->asDate('1922-08-12', 'dd-MM-yyyy'));
         $this->assertSame('14-01-1732', $this->formatter->asDate('1732-01-14', 'dd-MM-yyyy'));
+        $this->assertSame('01-01-0000', $this->formatter->asDate('0000-01-01', 'dd-MM-yyyy'));
     }
 
     public function testIntlDateRangeHigh()
     {
-        if (PHP_INT_SIZE == 4) { // 32bit systems
-            $this->markTestSkipped('intl does not support high date ranges on 32bit systems.');
-        }
+        // intl does not support high date ranges on 32bit systems, the implementation uses a fallback to PHP formatter
         $this->testDateRangeHigh();
     }
 
@@ -214,6 +211,7 @@ class FormatterDateTest extends TestCase
     {
         $this->assertSame('17-12-2048', $this->formatter->asDate('2048-12-17', 'dd-MM-yyyy'));
         $this->assertSame('17-12-3048', $this->formatter->asDate('3048-12-17', 'dd-MM-yyyy'));
+        $this->assertSame('31-12-9999', $this->formatter->asDate('9999-12-31', 'dd-MM-yyyy'));
     }
 
     private function buildDateSubIntervals($referenceDate, $intervals)