From c6acfadd71eb97e57fbe6a390bb98a96989278b4 Mon Sep 17 00:00:00 2001
From: Bernie Reiter <ockham@raz.or.at>
Date: Wed, 20 Aug 2025 15:10:19 +0200
Subject: [PATCH 1/2] Block Bindings Processor: Tweak test to break with
 current implementation

---
 .../phpunit/tests/block-bindings/wpBlockBindingsProcessor.php  | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tests/phpunit/tests/block-bindings/wpBlockBindingsProcessor.php b/tests/phpunit/tests/block-bindings/wpBlockBindingsProcessor.php
index 5a8cf11095847..d7f20099c000e 100644
--- a/tests/phpunit/tests/block-bindings/wpBlockBindingsProcessor.php
+++ b/tests/phpunit/tests/block-bindings/wpBlockBindingsProcessor.php
@@ -79,10 +79,11 @@ public function test_replace_rich_text_and_seek() {
 		$this->assertTrue( $processor->replace_rich_text( '<strong>New</strong> image caption' ) );
 
 		$processor->seek( 'image' );
+		$processor->add_class( 'extra-img-class' );
 
 		$this->assertEquals(
 			$figure_opener .
-			$img .
+			'<img src="breakfast.jpg" alt="" class="wp-image-1 extra-img-class"/>' .
 			'<figcaption class="wp-element-caption"><strong>New</strong> image caption</figcaption>' .
 			$figure_closer,
 			$processor->build()

From 1a61046ed49aef907df42af6ebf06d30e745932a Mon Sep 17 00:00:00 2001
From: Bernie Reiter <ockham@raz.or.at>
Date: Wed, 20 Aug 2025 15:11:23 +0200
Subject: [PATCH 2/2] Block Bindings Processor: Base implementation on
 WP_HTML_Text_Replacement to fix broken test

---
 .../class-wp-block-bindings-processor.php     | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/src/wp-includes/class-wp-block-bindings-processor.php b/src/wp-includes/class-wp-block-bindings-processor.php
index f833b9ed07562..4bf904d1d7bc9 100644
--- a/src/wp-includes/class-wp-block-bindings-processor.php
+++ b/src/wp-includes/class-wp-block-bindings-processor.php
@@ -26,11 +26,9 @@
  * @since 6.9.0
  */
 class WP_Block_Bindings_Processor extends WP_HTML_Processor {
-	private $output         = '';
-	private $end_of_flushed = 0;
 
 	public function build() {
-		return $this->output . substr( $this->get_updated_html(), $this->end_of_flushed );
+		return $this->get_updated_html();
 	}
 
 	/**
@@ -51,9 +49,8 @@ public function replace_rich_text( $rich_text ) {
 
 		$this->set_bookmark( '_wp_block_bindings_tag_opener' );
 		// The bookmark names are prefixed with `_` so the key below has an extra `_`.
-		$bm            = $this->bookmarks['__wp_block_bindings_tag_opener'];
-		$this->output .= substr( $this->get_updated_html(), $this->end_of_flushed, $bm->start + $bm->length );
-		$this->output .= $rich_text;
+		$bm    = $this->bookmarks['__wp_block_bindings_tag_opener'];
+		$start = $bm->start + $bm->length;
 		$this->release_bookmark( '_wp_block_bindings_tag_opener' );
 
 		// Find matching tag closer.
@@ -61,10 +58,16 @@ public function replace_rich_text( $rich_text ) {
 		}
 
 		$this->set_bookmark( '_wp_block_bindings_tag_closer' );
-		$bm                   = $this->bookmarks['__wp_block_bindings_tag_closer'];
-		$this->end_of_flushed = $bm->start;
+		$bm  = $this->bookmarks['__wp_block_bindings_tag_closer'];
+		$end = $bm->start;
 		$this->release_bookmark( '_wp_block_bindings_tag_closer' );
 
+		$this->lexical_updates[] = new WP_HTML_Text_Replacement(
+			$start,
+			$end - $start,
+			$rich_text
+		);
+
 		return true;
 	}
 }