From b08dd682275dc436ef9c0bd51b8f1535bcef1396 Mon Sep 17 00:00:00 2001
From: Mariusz Szatkowski <19728801+wppoland@users.noreply.github.com>
Date: Fri, 28 Aug 2026 16:22:27 +0200
Subject: [PATCH] HTML API: Add a serialization regression test for enqueued
 attribute updates.

[62960] made get_attribute_names_with_prefix() respect enqueued updates, but
its tests only cover WP_HTML_Tag_Processor. WP_HTML_Processor::serialize_token()
consumed the same stale name list while reading values through get_attribute(),
so a removed attribute was re-emitted as a value-less attribute and an added one
was dropped. That path gained no coverage.

Fails at [62960]^ with '<div onclick class="x">', passes on trunk.

Both assertions pin the full serialized output. A newly added attribute is
emitted before the existing ones, so the set_attribute() case is deterministic
and does not need a substring match (per @irozum's review).

Rebased onto trunk.

See #64567.
---
 .../html-api/wpHtmlProcessor-serialize.php    | 35 +++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/tests/phpunit/tests/html-api/wpHtmlProcessor-serialize.php b/tests/phpunit/tests/html-api/wpHtmlProcessor-serialize.php
index 1ce8855305ae9..100ee38cab2ea 100644
--- a/tests/phpunit/tests/html-api/wpHtmlProcessor-serialize.php
+++ b/tests/phpunit/tests/html-api/wpHtmlProcessor-serialize.php
@@ -853,4 +853,39 @@ public static function data_provider_normalize_special_leading_newline_cases():
 			),
 		);
 	}
+
+	/**
+	 * Ensures that serialize_token() reflects enqueued attribute updates instead
+	 * of emitting removed attributes as value-less attributes or omitting added ones.
+	 *
+	 * serialize_token() iterates the names from get_attribute_names_with_prefix( '' )
+	 * but reads each value through get_attribute(). Before #64567 the name list did not
+	 * reflect enqueued updates while the values did, so a removed attribute survived in
+	 * the output as a boolean attribute and an added attribute was dropped entirely.
+	 *
+	 * @ticket 64567
+	 *
+	 * @covers WP_HTML_Processor::serialize_token
+	 */
+	public function test_serialize_token_reflects_enqueued_attribute_updates() {
+		$processor = WP_HTML_Processor::create_fragment( '<div onclick="alert(1)" class="x">Text</div>' );
+		$processor->next_tag();
+		$processor->remove_attribute( 'onclick' );
+
+		$this->assertSame(
+			'<div class="x">',
+			$processor->serialize_token(),
+			'An attribute enqueued for removal was serialized as a value-less attribute.'
+		);
+
+		$processor = WP_HTML_Processor::create_fragment( '<div class="x">Text</div>' );
+		$processor->next_tag();
+		$processor->set_attribute( 'id', 'new' );
+
+		$this->assertSame(
+			'<div id="new" class="x">',
+			$processor->serialize_token(),
+			'An attribute enqueued via set_attribute() was not serialized. A newly added attribute is emitted before the existing ones.'
+		);
+	}
 }