From dd2bcd86b4acf7bcfeece652a8cdfac79ba35be4 Mon Sep 17 00:00:00 2001
From: Marin Atanasov <8436925+tyxla@users.noreply.github.com>
Date: Mon, 20 Jul 2026 10:45:12 +0300
Subject: [PATCH 1/2] Block Supports: Handle nested array block gap values
 properly

---
 lib/block-supports/layout.php          |  2 +-
 phpunit/block-supports/layout-test.php | 44 ++++++++++++++++++++++++++
 2 files changed, 45 insertions(+), 1 deletion(-)

diff --git a/lib/block-supports/layout.php b/lib/block-supports/layout.php
index 44e95a44be7248..7a93a510dbbddd 100644
--- a/lib/block-supports/layout.php
+++ b/lib/block-supports/layout.php
@@ -290,7 +290,7 @@ function gutenberg_get_layout_container_values( $layout ) {
 function gutenberg_sanitize_block_gap_value( $gap_value ) {
 	if ( is_array( $gap_value ) ) {
 		foreach ( $gap_value as $key => $value ) {
-			$gap_value[ $key ] = $value && preg_match( '%[\\\(&=}]|/\*%', $value ) ? null : $value;
+			$gap_value[ $key ] = ! is_scalar( $value ) || ( $value && preg_match( '%[\\\(&=}]|/\*%', (string) $value ) ) ? null : $value;
 		}
 		return $gap_value;
 	}
diff --git a/phpunit/block-supports/layout-test.php b/phpunit/block-supports/layout-test.php
index bf38867e91ee10..1a27f947622ccd 100644
--- a/phpunit/block-supports/layout-test.php
+++ b/phpunit/block-supports/layout-test.php
@@ -72,6 +72,24 @@ public function filter_set_theme_root() {
 		return $this->theme_root;
 	}
 
+	/**
+	 * @covers ::gutenberg_sanitize_block_gap_value
+	 */
+	public function test_sanitize_block_gap_value_rejects_nested_array_values() {
+		$this->assertSame(
+			array(
+				'top'  => null,
+				'left' => '2rem',
+			),
+			gutenberg_sanitize_block_gap_value(
+				array(
+					'top'  => array( '1rem' ),
+					'left' => '2rem',
+				)
+			)
+		);
+	}
+
 	public function test_outer_container_not_restored_for_non_aligned_image_block_with_non_themejson_theme() {
 		// The "default" theme doesn't have theme.json support.
 		switch_theme( 'default' );
@@ -636,6 +654,32 @@ public function data_layout_support_flag_renders_classnames_on_wrapper() {
 				),
 				'expected_output' => '<div class="wp-block-group is-layout-flow wp-block-group-is-layout-flow"></div>',
 			),
+			'single wrapper block layout with malformed axial block gap' => array(
+				'args'            => array(
+					'block_content' => '<div class="wp-block-group"></div>',
+					'block'         => array(
+						'blockName'    => 'core/group',
+						'attrs'        => array(
+							'layout' => array(
+								'type' => 'default',
+							),
+							'style'  => array(
+								'spacing' => array(
+									'blockGap' => array(
+										'top' => array( '1rem' ),
+									),
+								),
+							),
+						),
+						'innerBlocks'  => array(),
+						'innerHTML'    => '<div class="wp-block-group"></div>',
+						'innerContent' => array(
+							'<div class="wp-block-group"></div>',
+						),
+					),
+				),
+				'expected_output' => '<div class="wp-block-group is-layout-flow wp-block-group-is-layout-flow"></div>',
+			),
 			'single wrapper block layout with constrained type' => array(
 				'args'            => array(
 					'block_content' => '<div class="wp-block-group"></div>',

From 673ebeb0638dfc2d85daafe8e22b98a6fde8a654 Mon Sep 17 00:00:00 2001
From: Marin Atanasov <8436925+tyxla@users.noreply.github.com>
Date: Mon, 20 Jul 2026 11:13:36 +0300
Subject: [PATCH 2/2] Backport Changelog: Add entry for Core PR 12604

---
 backport-changelog/7.1/12604.md | 3 +++
 1 file changed, 3 insertions(+)
 create mode 100644 backport-changelog/7.1/12604.md

diff --git a/backport-changelog/7.1/12604.md b/backport-changelog/7.1/12604.md
new file mode 100644
index 00000000000000..62faed63df4653
--- /dev/null
+++ b/backport-changelog/7.1/12604.md
@@ -0,0 +1,3 @@
+https://github.com/WordPress/wordpress-develop/pull/12604
+
+* https://github.com/WordPress/gutenberg/pull/80464