Add throw on every special element

Author: sirreal

src/wp-includes/html-api/class-wp-html-processor.php

@@ -603,6 +603,185 @@ private function step_in_body() {
 		$op       = "{$op_sigil}{$tag_name}";
 
 		switch ( $op ) {
+			/*
+			 * These tags require special handling in the 'in body' insertion mode
+			 * but do not have special handling implemented yet.
+			 *
+			 * We throw the WP_HTML_Unsupported_Exception so we're free to implememnt
+			 * the catch-all handling for any other start and end tag.
+			 *
+			 * @see https://html.spec.whatwg.org/multipage/parsing.html#parsing-main-inbody
+			 */
+			case '+A':
+			case '+ADDRESS':
+			case '+APPLET':
+			case '+AREA':
+			case '+ARTICLE':
+			case '+ASIDE':
+			case '+B':
+			case '+BASE':
+			case '+BASEFONT':
+			case '+BGSOUND':
+			case '+BIG':
+			case '+BLOCKQUOTE':
+			case '+BODY':
+			case '+BR':
+			case '+BUTTON':
+			case '+CAPTION':
+			case '+CENTER':
+			case '+CODE':
+			case '+COL':
+			case '+COLGROUP':
+			case '+DD':
+			case '+DETAILS':
+			case '+DIALOG':
+			case '+DIR':
+			case '+DIV':
+			case '+DL':
+			case '+DT':
+			case '+EM':
+			case '+EMBED':
+			case '+FIELDSET':
+			case '+FIGCAPTION':
+			case '+FIGURE':
+			case '+FONT':
+			case '+FOOTER':
+			case '+FORM':
+			case '+FRAME':
+			case '+FRAMESET':
+			case '+H1':
+			case '+H2':
+			case '+H3':
+			case '+H4':
+			case '+H5':
+			case '+H6':
+			case '+HEAD':
+			case '+HEADER':
+			case '+HGROUP':
+			case '+HR':
+			case '+HTML':
+			case '+I':
+			case '+IFRAME':
+			case '+IMAGE':
+			case '+IMG':
+			case '+INPUT':
+			case '+KEYGEN':
+			case '+LI':
+			case '+LINK':
+			case '+LISTING':
+			case '+MAIN':
+			case '+MARQUEE':
+			case '+MATH':
+			case '+MENU':
+			case '+META':
+			case '+NAV':
+			case '+NOBR':
+			case '+NOEMBED':
+			case '+NOFRAMES':
+			case '+NOSCRIPT': // scripting flag??
+			case '+OBJECT':
+			case '+OL':
+			case '+OPTGROUP':
+			case '+OPTION':
+			case '+P':
+			case '+PARAM':
+			case '+PLAINTEXT':
+			case '+PRE':
+			case '+RB':
+			case '+RP':
+			case '+RT':
+			case '+RTC':
+			case '+S':
+			case '+SCRIPT':
+			case '+SEARCH':
+			case '+SECTION':
+			case '+SELECT':
+			case '+SMALL':
+			case '+SOURCE':
+			case '+STRIKE':
+			case '+STRONG':
+			case '+STYLE':
+			case '+SUMMARY':
+			case '+SVG':
+			case '+TABLE':
+			case '+TBODY':
+			case '+TD':
+			case '+TEMPLATE':
+			case '+TEXTAREA':
+			case '+TFOOT':
+			case '+TH':
+			case '+THEAD':
+			case '+TITLE':
+			case '+TR':
+			case '+TRACK':
+			case '+TT':
+			case '+U':
+			case '+UL':
+			case '+WBR':
+			case '+XMP':
+			case '-A':
+			case '-ADDRESS':
+			case '-APPLET':
+			case '-ARTICLE':
+			case '-ASIDE':
+			case '-B':
+			case '-BIG':
+			case '-BLOCKQUOTE':
+			case '-BODY':
+			case '-BR':
+			case '-BUTTON':
+			case '-CENTER':
+			case '-CODE':
+			case '-DD':
+			case '-DETAILS':
+			case '-DIALOG':
+			case '-DIR':
+			case '-DIV':
+			case '-DL':
+			case '-DT':
+			case '-EM':
+			case '-FIELDSET':
+			case '-FIGCAPTION':
+			case '-FIGURE':
+			case '-FONT':
+			case '-FOOTER':
+			case '-FORM':
+			case '-H1':
+			case '-H2':
+			case '-H3':
+			case '-H4':
+			case '-H5':
+			case '-H6':
+			case '-HEADER':
+			case '-HGROUP':
+			case '-HTML':
+			case '-I':
+			case '-LI':
+			case '-LISTING':
+			case '-MAIN':
+			case '-MARQUEE':
+			case '-MENU':
+			case '-NAV':
+			case '-NOBR':
+			case '-OBJECT':
+			case '-OL':
+			case '-P':
+			case '-PRE':
+			case '-S':
+			case '-SEARCH':
+			case '-SECTION':
+			case '-SMALL':
+			case '-STRIKE':
+			case '-STRONG':
+			case '-SUMMARY':
+			case '-TEMPLATE':
+			case '-TT':
+			case '-U':
+			case '-UL':
+				$this->last_error = self::ERROR_UNSUPPORTED;
+				throw new WP_HTML_Unsupported_Exception( "Cannot process {$tag_name} element." );
+
+
 			/*
 			 * > A start tag whose tag name is "button"
 			 */