Carry the source div marker on description-list rows

php-transformer/src/HtmlToBlocks/Generators/DescriptionListBlockGenerator.php

@@ -340,8 +340,13 @@ private function item(DOMElement $element): array
     /** @return array<string, mixed> */
     private function wrapper(DOMElement $element): array
     {
+        // Author type selectors such as `dl div` are rewritten to the source
+        // tag marker; persist it on the row so the projected rule still matches.
         $wrapper = array_filter(array(
-            'className' => $element->getAttribute('class'),
+            'className' => SourceDom::mergeClassNames(
+                $element->getAttribute('class'),
+                $this->session?->authorSelectorProjectionState()->tagMarker($element->tagName) ?? ''
+            ),
             'style' => $element->getAttribute('style'),
         ), static fn (mixed $value): bool => '' !== $value);
         $attributes = array();

php-transformer/tests/unit/description-list-source-tag-selector.php

@@ -0,0 +1,56 @@
+<?php
+declare(strict_types=1);
+
+require dirname(__DIR__, 2) . '/vendor/autoload.php';
+
+use Automattic\BlocksEngine\PhpTransformer\Css\CssSelectorMatcher;
+use Automattic\BlocksEngine\PhpTransformer\Css\CssStylesheetTransformer;
+use Automattic\BlocksEngine\PhpTransformer\HtmlToBlocks\HtmlTransformer;
+
+$assert = static function (bool $ok, string $message): void {
+    if ( ! $ok ) {
+        throw new RuntimeException($message);
+    }
+};
+
+// Author type selectors that reach description-list rows are rewritten to the
+// source div marker, so the generated rows must carry that marker to match.
+$html = '<style>.intro dl div{border-top:1px solid #ccc}dl + div{color:red}</style>'
+    . '<main><section class="intro"><dl><div><dt>Color story</dt><dd>Spring · Summer</dd></div><div><dt>Forms</dt><dd>Plates · Bowls</dd></div></dl><div>After</div></section></main>';
+$result = ( new HtmlTransformer() )->transform($html)->toArray();
+$assert('pass' === ($result['source_reports']['wp_block_validity']['status'] ?? null), 'Description-list rows with source markers stay editor-valid');
+
+$css = '';
+foreach ( $result['assets'] as $asset ) {
+    if ( 'author-css' === ($asset['source'] ?? '') ) {
+        $css .= (string) $asset['content'];
+    }
+}
+$projected = array();
+( new CssStylesheetTransformer() )->transformStyleRules($css, static function (string $selector, string $body) use (&$projected): string {
+    $projected[$body] = $selector;
+    return $selector . '{' . $body . '}';
+});
+
+$dom = new DOMDocument();
+$dom->loadHTML('<?xml encoding="UTF-8"><body>' . $result['serialized_blocks'] . '</body>', LIBXML_NOERROR);
+$xpath = new DOMXPath($dom);
+$rows = iterator_to_array($xpath->query('//dl/div'));
+$after = $xpath->query('//*[normalize-space(text())="After"]')->item(0);
+$assert(2 === count($rows) && $after instanceof DOMElement, 'Rows and the following sibling are rendered');
+
+foreach ( array(
+    'descendant row selector' => array( 'body' => 'border-top:1px solid #ccc', 'rows' => true, 'after' => false ),
+    'sibling selector stays rewritten' => array( 'body' => 'color:red', 'rows' => false, 'after' => true ),
+) as $case => $expected ) {
+    $selector = $projected[$expected['body']] ?? '';
+    $assert(1 !== preg_match('/(?:^|[\s>+~])div\b/', $selector), $case . ': the div type selector is rewritten to its source marker, got ' . $selector);
+    $parsed = CssSelectorMatcher::parse($selector);
+    $assert($parsed['supported'], $case . ': projected selector is matchable');
+    foreach ( $rows as $row ) {
+        $assert($expected['rows'] === CssSelectorMatcher::matches($row, $parsed)['matches'], $case . ': row match is ' . var_export($expected['rows'], true) . ' for ' . $selector . ' on ' . $dom->saveHTML($row));
+    }
+    $assert($expected['after'] === CssSelectorMatcher::matches($after, $parsed)['matches'], $case . ': following sibling match is ' . var_export($expected['after'], true));
+}
+
+echo "Description-list source tag selector passed\n";