fixup! WIP: Rely on Unicode processing within a RegExp pattern for ti…

…tle sanitization.

src/wp-includes/formatting.php

@@ -2712,50 +2712,111 @@ function slugify( string $sluggee ): string {
  */
 function sanitize_title_with_dashes( $title, $raw_title = '', $context = 'display' ) {
 	$title = strip_tags( $title );
+	// Preserve escaped octets.
+	$title = preg_replace( '|%([a-fA-F0-9][a-fA-F0-9])|', '---$1---', $title );
+	// Remove percent signs that are not part of an octet.
+	$title = str_replace( '%', '', $title );
+	// Restore octets.
+	$title = preg_replace( '|---([a-fA-F0-9][a-fA-F0-9])---|', '%$1', $title );
 
 	if ( seems_utf8( $title ) ) {
 		if ( function_exists( 'mb_strtolower' ) ) {
 			$title = mb_strtolower( $title, 'UTF-8' );
 		}
-
 		$title = utf8_uri_encode( $title, 200 );
 	}
 
 	$title = strtolower( $title );
 
 	if ( 'save' === $context ) {
-		$title = html_entity_decode( $title, ENT_QUOTES | ENT_SUBSTITUTE | ENT_HTML5 );
-		$title = rawurldecode( $title );
-		// Dash/hyphen symbols plus whitespace turn into a dash.
-		$title = preg_replace( '~[\p{Pd}\s/]+~u', '-', $title );
-		// Control characters, combining marks, symbols, punctuation, and invisible characters are removed.
-		$title = preg_replace_callback(
-			'~-[_-]+|[\p{C}\p{M}\p{S}\p{P}\p{Z}]+~u',
-			static function ( $chunk ) {
-				switch ( $chunk[0] ) {
-					case '-':
-						return '-';
-
-					case '_':
-						return '_';
-
-					default:
-						return '';
-				}
-			},
-			$title
-		);
+		// Convert &nbsp, &ndash, and &mdash to hyphens.
+		$title = str_replace( array( '%c2%a0', '%e2%80%93', '%e2%80%94' ), '-', $title );
+		// Convert &nbsp, &ndash, and &mdash HTML entities to hyphens.
+		$title = str_replace( array( ' ', ' ', '–', '–', '—', '—' ), '-', $title );
+		// Convert forward slash to hyphen.
+		$title = str_replace( '/', '-', $title );
+
+		// Strip these characters entirely.
 		$title = str_replace(
 			array(
-				"\xD7", // Replace multiplication sign "×" with "x".
-				'�',    // Remove invalid decoded characters.
+				// Soft hyphens.
+				'%c2%ad',
+				// &iexcl and &iquest.
+				'%c2%a1',
+				'%c2%bf',
+				// Angle quotes.
+				'%c2%ab',
+				'%c2%bb',
+				'%e2%80%b9',
+				'%e2%80%ba',
+				// Curly quotes.
+				'%e2%80%98',
+				'%e2%80%99',
+				'%e2%80%9c',
+				'%e2%80%9d',
+				'%e2%80%9a',
+				'%e2%80%9b',
+				'%e2%80%9e',
+				'%e2%80%9f',
+				// Bullet.
+				'%e2%80%a2',
+				// &copy, &reg, &deg, &hellip, and &trade.
+				'%c2%a9',
+				'%c2%ae',
+				'%c2%b0',
+				'%e2%80%a6',
+				'%e2%84%a2',
+				// Acute accents.
+				'%c2%b4',
+				'%cb%8a',
+				'%cc%81',
+				'%cd%81',
+				// Grave accent, macron, caron.
+				'%cc%80',
+				'%cc%84',
+				'%cc%8c',
+				// Non-visible characters that display without a width.
+				'%e2%80%8b', // Zero width space.
+				'%e2%80%8c', // Zero width non-joiner.
+				'%e2%80%8d', // Zero width joiner.
+				'%e2%80%8e', // Left-to-right mark.
+				'%e2%80%8f', // Right-to-left mark.
+				'%e2%80%aa', // Left-to-right embedding.
+				'%e2%80%ab', // Right-to-left embedding.
+				'%e2%80%ac', // Pop directional formatting.
+				'%e2%80%ad', // Left-to-right override.
+				'%e2%80%ae', // Right-to-left override.
+				'%ef%bb%bf', // Byte order mark.
+				'%ef%bf%bc', // Object replacement character.
 			),
+			'',
+			$title
+		);
+
+		// Convert non-visible characters that display with a width to hyphen.
+		$title = str_replace(
 			array(
-				'x',
-				'',
+				'%e2%80%80', // En quad.
+				'%e2%80%81', // Em quad.
+				'%e2%80%82', // En space.
+				'%e2%80%83', // Em space.
+				'%e2%80%84', // Three-per-em space.
+				'%e2%80%85', // Four-per-em space.
+				'%e2%80%86', // Six-per-em space.
+				'%e2%80%87', // Figure space.
+				'%e2%80%88', // Punctuation space.
+				'%e2%80%89', // Thin space.
+				'%e2%80%8a', // Hair space.
+				'%e2%80%a8', // Line separator.
+				'%e2%80%a9', // Paragraph separator.
+				'%e2%80%af', // Narrow no-break space.
 			),
+			'-',
 			$title
 		);
+
+		// Convert &times to 'x'.
+		$title = str_replace( '%c3%97', 'x', $title );
 	}
 
 	// Remove HTML entities.