Potential patch for 30180 https://core.trac.wordpress.org/attachment/ticket/30180/30180.patch

30180.1.diff

diff --git a/wp-admin/custom-header.php b/wp-admin/custom-header.php
index 9460c80ca6..dd7306e1c2 100644
--- a/wp-admin/custom-header.php
+++ b/wp-admin/custom-header.php
@@ -1461,12 +1461,10 @@ endif;
 	public function get_uploaded_header_images() {
 		$header_images = get_uploaded_header_images();
 		$timestamp_key = '_wp_attachment_custom_header_last_used_' . get_stylesheet();
-		$alt_text_key  = '_wp_attachment_image_alt';
 
 		foreach ( $header_images as &$header_image ) {
-			$header_meta               = get_post_meta( $header_image['attachment_id'] );
-			$header_image['timestamp'] = isset( $header_meta[ $timestamp_key ] ) ? $header_meta[ $timestamp_key ] : '';
-			$header_image['alt_text']  = isset( $header_meta[ $alt_text_key ] ) ? $header_meta[ $alt_text_key ] : '';
+			$header_image['timestamp'] = get_post_meta( $header_image['attachment_id'], 'timestamp', true );
+			$header_image['alt_text']  = wp_get_attachment_image_attr( $header_image['attachment_id'], 'alt' );
 		}
 
 		return $header_images;
diff --git a/wp-admin/includes/media.php b/wp-admin/includes/media.php
index 93eceeca3a..b7839f0525 100644
--- a/wp-admin/includes/media.php
+++ b/wp-admin/includes/media.php
@@ -1357,7 +1357,7 @@ function get_attachment_fields_to_edit( $post, $errors = null ) {
 
 	// This was formerly in image_attachment_fields_to_edit().
 	if ( substr( $post->post_mime_type, 0, 5 ) == 'image' ) {
-		$alt = get_post_meta( $post->ID, '_wp_attachment_image_alt', true );
+		$alt = wp_get_attachment_image_attr( $post->ID, 'alt' );
 		if ( empty( $alt ) ) {
 			$alt = '';
 		}
diff --git a/wp-includes/general-template.php b/wp-includes/general-template.php
index 434e3245a1..4dbc759c2f 100644
--- a/wp-includes/general-template.php
+++ b/wp-includes/general-template.php
@@ -905,7 +905,7 @@ function get_custom_logo( $blog_id = 0 ) {
 		 * If the logo alt attribute is empty, get the site title and explicitly
 		 * pass it to the attributes used by wp_get_attachment_image().
 		 */
-		$image_alt = get_post_meta( $custom_logo_id, '_wp_attachment_image_alt', true );
+		$image_alt = wp_get_attachment_image_attr( $custom_logo_id, 'alt' );
 		if ( empty( $image_alt ) ) {
 			$custom_logo_attr['alt'] = get_bloginfo( 'name', 'display' );
 		}
diff --git a/wp-includes/media.php b/wp-includes/media.php
index ec50703b33..fc100ecbdd 100644
--- a/wp-includes/media.php
+++ b/wp-includes/media.php
@@ -853,6 +853,170 @@ function wp_get_attachment_image_src( $attachment_id, $size = 'thumbnail', $icon
 	return apply_filters( 'wp_get_attachment_image_src', $image, $attachment_id, $size, $icon );
 }
 
+/**
+ * Retrieve an image attribute value.
+ *
+ * Retrieve either a single image attribute value or all relevant attribute values. The possible
+ * values are `alt`, `description`, `caption`, `src`, `width`, `height`, `srcset`, `sizes`, `class`. When
+ * retrieving src, width, height, srcset, sizes, or class, you can specify the size of the image to retrieve
+ * in the args parameter. Passing in an empty attribute value will return all relevant values.
+ *
+ * @since 5.X
+ *
+ * @param int          $attachment_id Image attachment ID.
+ * @param string|array $attribute     Image attribute to retrieve.
+ * @param array        $args          Optional. Array of attributes for the function. Currently only
+ *                                    supports 'size' for the image source.
+ * @return string|array               Returns the value of the attribute or attributes requested. A single
+ *                                    attribute will return a single value. An array of attributes or no
+ *                                    attribute will return an array of values.
+ */
+function wp_get_attachment_image_attr( $attachment_id, $attribute = [], $args = [] ) {
+	$image = get_post( $attachment_id );
+
+	// If this isn't an image, bail early with null.
+	if ( empty( $image ) ) {
+		return null;
+	}
+
+	$values = [];
+	$names  = [];
+
+	if ( empty( $attribute ) ) {
+		// If an empty value is passed for the attr name, return all our attributes.
+		$names = array(
+			'alt',
+			'description',
+			'caption',
+			'src',
+			'width',
+			'height',
+			'srcset',
+			'sizes',
+			'class',
+		);
+	} elseif ( is_string( $attribute ) ) {
+		// If the attribute name is a string, convert it to an array.
+		$names = array( $attribute );
+	}
+
+	// Get a valid args array.
+	$default_args = array(
+		'size' => null,
+	);
+
+	$args = wp_parse_args( $args, $default_args );
+
+	// Loop through our names and get the value for each one.
+	foreach ( $names as $name ) {
+		switch ( $name ) {
+			case 'alt':
+				$values[ $name ] = get_post_meta( $attachment_id, '_wp_attachment_image_alt', true );
+				break;
+
+			case 'description':
+				$values[ $name ] = $image->post_content;
+				break;
+
+			case 'caption':
+				$values[ $name ] = $image->post_excerpt;
+				break;
+
+			case 'src':
+				if ( ! isset( $image_src ) ) {
+					$image_src       = image_downsize( $attachment_id, $args['size'] );
+				}
+
+				$values[ $name ] = $image_src[0];
+				break;
+
+			case 'width':
+				if ( ! isset( $image_src ) ) {
+					$image_src       = image_downsize( $attachment_id, $args['size'] );
+				}
+
+				$values[ $name ] = $image_src[1];
+				break;
+
+			case 'height':
+				if ( ! isset( $image_src ) ) {
+					$image_src       = image_downsize( $attachment_id, $args['size'] );
+				}
+
+				$values[ $name ] = $image_src[2];
+				break;
+
+			case 'srcset':
+				$values[ $name ] = wp_get_attachment_image_srcset( $attachment_id, $args['size'] );
+				break;
+
+			case 'sizes':
+				$values[ $name ] = wp_get_attachment_image_sizes( $attachment_id, $args['size'] );
+				break;
+
+			case 'class':
+				$size_class = $args['size'];
+
+				if ( is_array( $size_class ) ) {
+					$size_class = join( 'x', $size_class );
+				}
+
+				$values[ $name ] = 'attachment-' . $size_class . ' size-' . $size_class;
+				break;
+		}
+	}
+
+	/**
+	 * Filters the image attr result.
+	 *
+	 * Will apply to all image attribute types.
+	 *
+	 * @since 5.x
+	 *
+	 * @param string|int $values         Value of the attribute.
+	 * @param int        $attachment_id Image attachment ID.
+	 * @param string     $name     Name of the attribute being retrieved.
+	 * @param array      $args          Arguments passed into the function.
+	 */
+	$values = apply_filters( 'wp_get_attachment_image_attr', $values, $attachment_id, $attribute, $args );
+
+	// If we didn't request a single attribute, we're done.
+	if ( is_array( $attribute ) || empty( $attribute ) ) {
+		return $values;
+	}
+
+	if ( ! empty( $values[ $attribute ] ) ) {
+		$value = $values[ $attribute ];
+	} else {
+		$value = null;
+	}
+
+	/**
+	 * Filters the image attr result.
+	 *
+	 * This is a dynamic filter that will generate a distinct filter for each attribute type.
+	 * It only runs if the requested attribute is a string.
+	 *
+	 * <code>
+	 * <?php
+	 * function filter_alt_text( $alt ) {
+	 *     $alt = $alt + ' Extra content';
+	 *     return $alt;
+	 * }
+	 * add_filter( 'wp_get_attachment_image_attr_alt', 'filter_alt_text' );
+	 * </code>
+	 *
+	 * @since 5.x
+	 *
+	 * @param string|int $value         Value of the attribute.
+	 * @param int        $attachment_id Image attachment ID.
+	 * @param array      $args          Arguments passed into the function.
+	 */
+	$value = apply_filters( 'wp_get_attachment_image_attr_' . $attribute, $value, $attachment_id, $args );
+
+	return $value;
+}
+
 /**
  * Get an HTML img element representing an image attachment
  *
diff --git a/wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php b/wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php
index e317f523aa..424f066025 100644
--- a/wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php
+++ b/wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php
@@ -308,7 +308,7 @@ class WP_REST_Attachments_Controller extends WP_REST_Posts_Controller {
 		}
 
 		if ( in_array( 'alt_text', $fields, true ) ) {
-			$data['alt_text'] = get_post_meta( $post->ID, '_wp_attachment_image_alt', true );
+			$data['alt_text'] = wp_get_attachment_image_attr( $post->ID, 'alt' );
 		}
 
 		if ( in_array( 'media_type', $fields, true ) ) {
diff --git a/wp-includes/theme.php b/wp-includes/theme.php
index 3d26800436..c45dfbdd40 100644
--- a/wp-includes/theme.php
+++ b/wp-includes/theme.php
@@ -1275,7 +1275,7 @@ function get_uploaded_header_images() {
 		$header_images[ $header_index ]['attachment_id']     = $header->ID;
 		$header_images[ $header_index ]['url']               = $url;
 		$header_images[ $header_index ]['thumbnail_url']     = $url;
-		$header_images[ $header_index ]['alt_text']          = get_post_meta( $header->ID, '_wp_attachment_image_alt', true );
+		$header_images[ $header_index ]['alt_text']          = wp_get_attachment_image_attr( $header->ID, 'alt' );
 		$header_images[ $header_index ]['attachment_parent'] = isset( $header_data['attachment_parent'] ) ? $header_data['attachment_parent'] : '';
 
 		if ( isset( $header_data['width'] ) ) {