refactor: Port to modern NLS implementation

lib/Horde/Date/Utils.php

@@ -146,9 +146,10 @@ public static function relativeDateTime(
     public static function strftime2date($format)
     {
         $provider = null;
-        if (class_exists('Horde_Nls')) {
-            $provider = function (int $constant): string {
-                return Horde_Nls::getLangInfo($constant);
+        if (class_exists(Horde\Nls\Nls::class)) {
+            $nls = new Horde\Nls\Nls();
+            $provider = function (int $constant) use ($nls): string|false {
+                return $nls->getLangInfo($constant);
             };
         }
         return Horde\Date\Utils::strftime2date((string) $format, $provider);

src/Utils.php

@@ -133,13 +133,19 @@ public static function strftime2date(
         $callbackPatterns = [
             '/%X/' => function () use ($localeInfoProvider): string {
                 if ($localeInfoProvider !== null) {
-                    return $localeInfoProvider(T_FMT);
+                    $result = $localeInfoProvider(T_FMT);
+                    if ($result !== false) {
+                        return $result;
+                    }
                 }
                 return 'H:i:s';
             },
             '/%x/' => function () use ($localeInfoProvider): string {
                 if ($localeInfoProvider !== null) {
-                    return $localeInfoProvider(D_FMT);
+                    $result = $localeInfoProvider(D_FMT);
+                    if ($result !== false) {
+                        return $result;
+                    }
                 }
                 return 'm/d/Y';
             },

test/Unit/UtilsTest.php

@@ -7,6 +7,7 @@
 use Horde\Date\Date;
 use Horde\Date\DateException;
 use Horde\Date\Utils;
+use Horde\Nls\Nls;
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
@@ -204,4 +205,34 @@ public function testStrftime2dateComposite(): void
     {
         $this->assertSame('Y-m-d H:i:s', Utils::strftime2date('%Y-%m-%d %H:%M:%S'));
     }
+
+    public function testStrftime2dateWithNlsProvider(): void
+    {
+        $nls = new Nls();
+        $provider = function (int $constant) use ($nls): string|false {
+            return $nls->getLangInfo($constant);
+        };
+
+        $dateFormat = Utils::strftime2date('%x', $provider);
+        $timeFormat = Utils::strftime2date('%X', $provider);
+
+        // nl_langinfo returns strftime format strings (e.g. %m/%d/%y)
+        // which are then converted by the second pass of strftime2date.
+        // Verify the provider's output is processed correctly end-to-end.
+        $expectedDate = Utils::strftime2date(nl_langinfo(D_FMT));
+        $expectedTime = Utils::strftime2date(nl_langinfo(T_FMT));
+
+        $this->assertSame($expectedDate, $dateFormat);
+        $this->assertSame($expectedTime, $timeFormat);
+    }
+
+    public function testStrftime2dateWithNlsProviderFalseReturnFallsBack(): void
+    {
+        $provider = function (int $constant): string|false {
+            return false;
+        };
+
+        $this->assertSame('m/d/Y', Utils::strftime2date('%x', $provider));
+        $this->assertSame('H:i:s', Utils::strftime2date('%X', $provider));
+    }
 }