Improve Host normalization

Author: nyamsprod

interfaces/Encoder.php

@@ -309,7 +309,7 @@ public static function normalizeHost(Stringable|string|null $host): ?string
 
         return (!str_contains($host, '%')) ? $host : preg_replace_callback(
             '/%[a-f0-9]{2}/',
-            fn (array $matches): string => strtoupper($matches[0]),
+            fn (array $matches) => 1 === preg_match('/%([0-7][0-9a-f])/', $matches[0]) ? rawurldecode($matches[0]) : strtoupper($matches[0]),
             $host
         );
     }

interfaces/UriString.php

@@ -32,12 +32,10 @@
 use function in_array;
 use function inet_pton;
 use function preg_match;
-use function preg_replace_callback;
 use function rawurldecode;
 use function sprintf;
 use function strpos;
 use function strtolower;
-use function strtoupper;
 use function substr;
 
 use const FILTER_FLAG_IPV4;
@@ -305,18 +303,11 @@ public static function parseNormalized(Stringable|string $uri): array
 
         $host = $components['host'];
         if (null !== $host && false === filter_var($host, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4)) {
-            $host = (string) IPv6Converter::normalize($host);
-            if ($host === $components['host']) {
-                $host = (string) preg_replace_callback(
-                    '/%[0-9A-F]{2}/i',
-                    fn (array $matches): string => strtoupper($matches[0]),
-                    strtolower($host)
-                );
-                if ($isSupported) {
-                    $idnaHost = IdnaConverter::toAscii(rawurldecode($components['host']));
-                    if (!$idnaHost->hasErrors()) {
-                        $host = $idnaHost->domain();
-                    }
+            $host = (string) Encoder::normalizeHost($host);
+            if ($isSupported) {
+                $idnaHost = IdnaConverter::toAscii($host);
+                if (!$idnaHost->hasErrors()) {
+                    $host = $idnaHost->domain();
                 }
             }
 
@@ -782,10 +773,6 @@ public static function isHost(Stringable|string|null $host): bool
      */
     private static function filterRegisteredName(string $host): void
     {
-        if ($host !== Encoder::decodeUnreservedCharacters($host)) {
-            throw new SyntaxError('Host `'.$host.'` is invalid: only UTF-8 characters sequence can be percent encoded in host.');
-        }
-
         $formattedHost = rawurldecode($host);
         if ($formattedHost !== $host) {
             if (IdnaConverter::toAscii($formattedHost)->hasErrors()) {

interfaces/UriStringTest.php

@@ -745,7 +745,6 @@ public static function invalidUriProvider(): array
             'invalid port (1)' => ['//host:port/path?query#fragment'],
             'invalid port (2)' => ['//host:-892358/path?query#fragment'],
             'invalid host' => ['http://exam ple.com'],
-            'invalid host with invalid encoded characters' => ['http://ex%61mple.com'],
             'invalid ipv6 host (1)' => ['scheme://[127.0.0.1]/path?query#fragment'],
             'invalid ipv6 host (2)' => ['scheme://]::1[/path?query#fragment'],
             'invalid ipv6 host (3)' => ['scheme://[::1|/path?query#fragment'],

uri/Uri.php

@@ -76,7 +76,6 @@
 use function strpos;
 use function strspn;
 use function strtolower;
-use function strtoupper;
 use function substr;
 use function trim;
 
@@ -382,24 +381,19 @@ private function formatHost(?string $host): ?string
     private function formatRegisteredName(string $host): string
     {
         $formattedHost = rawurldecode($host);
-        if ($formattedHost !== $host) {
-
-            if (IdnaConverter::toAscii($formattedHost)->hasErrors()) {
-                throw new SyntaxError('The host `'.$host.'` is invalid : the registered name contains invalid characters.');
-            }
+        if ($formattedHost === $host) {
+            return match (1) {
+                preg_match(self::REGEXP_HOST_REGNAME, $formattedHost) => $formattedHost,
+                preg_match(self::REGEXP_HOST_GEN_DELIMS, $formattedHost) => throw new SyntaxError('The host `'.$host.'` is invalid : a registered name cannot contain URI delimiters or spaces.'),
+                default => IdnaConverter::toAsciiOrFail($host),
+            };
+        }
 
-            return (string) preg_replace_callback(
-                '/%[0-9A-F]{2}/i',
-                fn (array $matches) => strtoupper($matches[0]),
-                strtolower($host)
-            );
+        if (IdnaConverter::toAscii($formattedHost)->hasErrors()) {
+            throw new SyntaxError('The host `'.$host.'` is invalid : the registered name contains invalid characters.');
         }
 
-        return match (1) {
-            preg_match(self::REGEXP_HOST_REGNAME, $formattedHost) => $formattedHost,
-            preg_match(self::REGEXP_HOST_GEN_DELIMS, $formattedHost) => throw new SyntaxError('The host `'.$host.'` is invalid : a registered name cannot contain URI delimiters or spaces.'),
-            default => IdnaConverter::toAsciiOrFail($host),
-        };
+        return (string) Encoder::normalizeHost($host);
     }
 
     /**
@@ -1185,7 +1179,6 @@ public function toDisplayString(): string
     {
         $components = $this->toComponents();
 
-
         unset($components['port']);
         if (null !== $components['host']) {
             $components['host'] = IdnaConverter::toUnicode($components['host'])->domain();