wp/wp-includes/revision.php
changeset 21 48c4eec2b7e6
parent 19 3d72ae0968f4
child 22 8c2e4d02f4ef
--- a/wp/wp-includes/revision.php	Thu Sep 29 08:06:27 2022 +0200
+++ b/wp/wp-includes/revision.php	Fri Sep 05 18:40:08 2025 +0200
@@ -17,7 +17,7 @@
  * @param array|WP_Post $post       Optional. A post array or a WP_Post object being processed
  *                                  for insertion as a post revision. Default empty array.
  * @param bool          $deprecated Not used.
- * @return array Array of fields that can be versioned.
+ * @return string[] Array of fields that can be versioned.
  */
 function _wp_post_revision_fields( $post = array(), $deprecated = false ) {
 	static $fields = null;
@@ -47,9 +47,9 @@
 	 * @since 2.6.0
 	 * @since 4.5.0 The `$post` parameter was added.
 	 *
-	 * @param array $fields List of fields to revision. Contains 'post_title',
-	 *                      'post_content', and 'post_excerpt' by default.
-	 * @param array $post   A post array being processed for insertion as a post revision.
+	 * @param string[] $fields List of fields to revision. Contains 'post_title',
+	 *                         'post_content', and 'post_excerpt' by default.
+	 * @param array    $post   A post array being processed for insertion as a post revision.
 	 */
 	$fields = apply_filters( '_wp_post_revision_fields', $fields, $post );
 
@@ -96,6 +96,27 @@
 }
 
 /**
+ * Saves revisions for a post after all changes have been made.
+ *
+ * @since 6.4.0
+ *
+ * @param int     $post_id The post id that was inserted.
+ * @param WP_Post $post    The post object that was inserted.
+ * @param bool    $update  Whether this insert is updating an existing post.
+ */
+function wp_save_post_revision_on_insert( $post_id, $post, $update ) {
+	if ( ! $update ) {
+		return;
+	}
+
+	if ( ! has_action( 'post_updated', 'wp_save_post_revision' ) ) {
+		return;
+	}
+
+	wp_save_post_revision( $post_id );
+}
+
+/**
  * Creates a revision for the current version of a post.
  *
  * Typically used immediately after a post update, as every update is a revision,
@@ -111,7 +132,13 @@
 		return;
 	}
 
+	// Prevent saving post revisions if revisions should be saved on wp_after_insert_post.
+	if ( doing_action( 'post_updated' ) && has_action( 'wp_after_insert_post', 'wp_save_post_revision_on_insert' ) ) {
+		return;
+	}
+
 	$post = get_post( $post_id );
+
 	if ( ! $post ) {
 		return;
 	}
@@ -135,16 +162,16 @@
 	 */
 	$revisions = wp_get_post_revisions( $post_id );
 	if ( $revisions ) {
-		// Grab the last revision, but not an autosave.
+		// Grab the latest revision, but not an autosave.
 		foreach ( $revisions as $revision ) {
-			if ( false !== strpos( $revision->post_name, "{$revision->post_parent}-revision" ) ) {
-				$last_revision = $revision;
+			if ( str_contains( $revision->post_name, "{$revision->post_parent}-revision" ) ) {
+				$latest_revision = $revision;
 				break;
 			}
 		}
 
 		/**
-		 * Filters whether the post has changed since the last revision.
+		 * Filters whether the post has changed since the latest revision.
 		 *
 		 * By default a revision is saved only if one of the revisioned fields has changed.
 		 * This filter can override that so a revision is saved even if nothing has changed.
@@ -153,14 +180,14 @@
 		 *
 		 * @param bool    $check_for_changes Whether to check for changes before saving a new revision.
 		 *                                   Default true.
-		 * @param WP_Post $last_revision     The last revision post object.
+		 * @param WP_Post $latest_revision   The latest revision post object.
 		 * @param WP_Post $post              The post object.
 		 */
-		if ( isset( $last_revision ) && apply_filters( 'wp_save_post_revision_check_for_changes', true, $last_revision, $post ) ) {
+		if ( isset( $latest_revision ) && apply_filters( 'wp_save_post_revision_check_for_changes', true, $latest_revision, $post ) ) {
 			$post_has_changed = false;
 
 			foreach ( array_keys( _wp_post_revision_fields( $post ) ) as $field ) {
-				if ( normalize_whitespace( $post->$field ) !== normalize_whitespace( $last_revision->$field ) ) {
+				if ( normalize_whitespace( $post->$field ) !== normalize_whitespace( $latest_revision->$field ) ) {
 					$post_has_changed = true;
 					break;
 				}
@@ -175,10 +202,10 @@
 			 * @since 4.1.0
 			 *
 			 * @param bool    $post_has_changed Whether the post has changed.
-			 * @param WP_Post $last_revision    The last revision post object.
+			 * @param WP_Post $latest_revision  The latest revision post object.
 			 * @param WP_Post $post             The post object.
 			 */
-			$post_has_changed = (bool) apply_filters( 'wp_save_post_revision_post_has_changed', $post_has_changed, $last_revision, $post );
+			$post_has_changed = (bool) apply_filters( 'wp_save_post_revision_post_has_changed', $post_has_changed, $latest_revision, $post );
 
 			// Don't save revision if post unchanged.
 			if ( ! $post_has_changed ) {
@@ -189,8 +216,10 @@
 
 	$return = _wp_put_post_revision( $post );
 
-	// If a limit for the number of revisions to keep has been set,
-	// delete the oldest ones.
+	/*
+	 * If a limit for the number of revisions to keep has been set,
+	 * delete the oldest ones.
+	 */
 	$revisions_to_keep = wp_revisions_to_keep( $post );
 
 	if ( $revisions_to_keep < 0 ) {
@@ -199,6 +228,20 @@
 
 	$revisions = wp_get_post_revisions( $post_id, array( 'order' => 'ASC' ) );
 
+	/**
+	 * Filters the revisions to be considered for deletion.
+	 *
+	 * @since 6.2.0
+	 *
+	 * @param WP_Post[] $revisions Array of revisions, or an empty array if none.
+	 * @param int       $post_id   The ID of the post to save as a revision.
+	 */
+	$revisions = apply_filters(
+		'wp_save_post_revision_revisions_before_deletion',
+		$revisions,
+		$post_id
+	);
+
 	$delete = count( $revisions ) - $revisions_to_keep;
 
 	if ( $delete < 1 ) {
@@ -208,7 +251,7 @@
 	$revisions = array_slice( $revisions, 0, $delete );
 
 	for ( $i = 0; isset( $revisions[ $i ] ); $i++ ) {
-		if ( false !== strpos( $revisions[ $i ]->post_name, 'autosave' ) ) {
+		if ( str_contains( $revisions[ $i ]->post_name, 'autosave' ) ) {
 			continue;
 		}
 
@@ -219,7 +262,7 @@
 }
 
 /**
- * Retrieve the autosaved data of the specified post.
+ * Retrieves the autosaved data of the specified post.
  *
  * Returns a post object with the information that was autosaved for the specified post.
  * If the optional $user_id is passed, returns the autosave for that user, otherwise
@@ -230,7 +273,7 @@
  * @global wpdb $wpdb WordPress database abstraction object.
  *
  * @param int $post_id The post ID.
- * @param int $user_id Optional The post author ID.
+ * @param int $user_id Optional. The post author ID. Default 0.
  * @return WP_Post|false The autosaved data or false on failure or when no autosave exists.
  */
 function wp_get_post_autosave( $post_id, $user_id = 0 ) {
@@ -275,6 +318,7 @@
  */
 function wp_is_post_revision( $post ) {
 	$post = wp_get_post_revision( $post );
+
 	if ( ! $post ) {
 		return false;
 	}
@@ -292,11 +336,12 @@
  */
 function wp_is_post_autosave( $post ) {
 	$post = wp_get_post_revision( $post );
+
 	if ( ! $post ) {
 		return false;
 	}
 
-	if ( false !== strpos( $post->post_name, "{$post->post_parent}-autosave" ) ) {
+	if ( str_contains( $post->post_name, "{$post->post_parent}-autosave" ) ) {
 		return (int) $post->post_parent;
 	}
 
@@ -310,7 +355,8 @@
  * @access private
  *
  * @param int|WP_Post|array|null $post     Post ID, post object OR post array.
- * @param bool                   $autosave Optional. Is the revision an autosave?
+ * @param bool                   $autosave Optional. Whether the revision is an autosave or not.
+ *                                         Default false.
  * @return int|WP_Error WP_Error or 0 if error, new revision ID if success.
  */
 function _wp_put_post_revision( $post = null, $autosave = false ) {
@@ -341,32 +387,58 @@
 		 * Fires once a revision has been saved.
 		 *
 		 * @since 2.6.0
+		 * @since 6.4.0 The post_id parameter was added.
 		 *
 		 * @param int $revision_id Post revision ID.
+		 * @param int $post_id     Post ID.
 		 */
-		do_action( '_wp_put_post_revision', $revision_id );
+		do_action( '_wp_put_post_revision', $revision_id, $post['post_parent'] );
 	}
 
 	return $revision_id;
 }
 
+
+/**
+ * Save the revisioned meta fields.
+ *
+ * @since 6.4.0
+ *
+ * @param int $revision_id The ID of the revision to save the meta to.
+ * @param int $post_id     The ID of the post the revision is associated with.
+ */
+function wp_save_revisioned_meta_fields( $revision_id, $post_id ) {
+	$post_type = get_post_type( $post_id );
+	if ( ! $post_type ) {
+		return;
+	}
+
+	foreach ( wp_post_revision_meta_keys( $post_type ) as $meta_key ) {
+		if ( metadata_exists( 'post', $post_id, $meta_key ) ) {
+			_wp_copy_post_meta( $post_id, $revision_id, $meta_key );
+		}
+	}
+}
+
 /**
  * Gets a post revision.
  *
  * @since 2.6.0
  *
- * @param int|WP_Post $post   The post ID or object.
+ * @param int|WP_Post $post   Post ID or post object.
  * @param string      $output Optional. The required return type. One of OBJECT, ARRAY_A, or ARRAY_N, which
  *                            correspond to a WP_Post object, an associative array, or a numeric array,
  *                            respectively. Default OBJECT.
- * @param string      $filter Optional sanitation filter. See sanitize_post().
+ * @param string      $filter Optional sanitization filter. See sanitize_post(). Default 'raw'.
  * @return WP_Post|array|null WP_Post (or array) on success, or null on failure.
  */
 function wp_get_post_revision( &$post, $output = OBJECT, $filter = 'raw' ) {
 	$revision = get_post( $post, OBJECT, $filter );
+
 	if ( ! $revision ) {
 		return $revision;
 	}
+
 	if ( 'revision' !== $revision->post_type ) {
 		return null;
 	}
@@ -391,12 +463,13 @@
  *
  * @since 2.6.0
  *
- * @param int|WP_Post $revision_id Revision ID or revision object.
- * @param array       $fields      Optional. What fields to restore from. Defaults to all.
+ * @param int|WP_Post $revision Revision ID or revision object.
+ * @param array       $fields   Optional. What fields to restore from. Defaults to all.
  * @return int|false|null Null if error, false if no fields to restore, (int) post ID if success.
  */
-function wp_restore_post_revision( $revision_id, $fields = null ) {
-	$revision = wp_get_post_revision( $revision_id, ARRAY_A );
+function wp_restore_post_revision( $revision, $fields = null ) {
+	$revision = wp_get_post_revision( $revision, ARRAY_A );
+
 	if ( ! $revision ) {
 		return $revision;
 	}
@@ -419,6 +492,7 @@
 	$update = wp_slash( $update ); // Since data is from DB.
 
 	$post_id = wp_update_post( $update );
+
 	if ( ! $post_id || is_wp_error( $post_id ) ) {
 		return $post_id;
 	}
@@ -440,22 +514,123 @@
 }
 
 /**
+ * Restore the revisioned meta values for a post.
+ *
+ * @since 6.4.0
+ *
+ * @param int $post_id     The ID of the post to restore the meta to.
+ * @param int $revision_id The ID of the revision to restore the meta from.
+ */
+function wp_restore_post_revision_meta( $post_id, $revision_id ) {
+	$post_type = get_post_type( $post_id );
+	if ( ! $post_type ) {
+		return;
+	}
+
+	// Restore revisioned meta fields.
+	foreach ( wp_post_revision_meta_keys( $post_type ) as $meta_key ) {
+
+		// Clear any existing meta.
+		delete_post_meta( $post_id, $meta_key );
+
+		_wp_copy_post_meta( $revision_id, $post_id, $meta_key );
+	}
+}
+
+/**
+ * Copy post meta for the given key from one post to another.
+ *
+ * @since 6.4.0
+ *
+ * @param int    $source_post_id Post ID to copy meta value(s) from.
+ * @param int    $target_post_id Post ID to copy meta value(s) to.
+ * @param string $meta_key       Meta key to copy.
+ */
+function _wp_copy_post_meta( $source_post_id, $target_post_id, $meta_key ) {
+
+	foreach ( get_post_meta( $source_post_id, $meta_key ) as $meta_value ) {
+		/**
+		 * We use add_metadata() function vs add_post_meta() here
+		 * to allow for a revision post target OR regular post.
+		 */
+		add_metadata( 'post', $target_post_id, $meta_key, wp_slash( $meta_value ) );
+	}
+}
+
+/**
+ * Determine which post meta fields should be revisioned.
+ *
+ * @since 6.4.0
+ *
+ * @param string $post_type The post type being revisioned.
+ * @return array An array of meta keys to be revisioned.
+ */
+function wp_post_revision_meta_keys( $post_type ) {
+	$registered_meta = array_merge(
+		get_registered_meta_keys( 'post' ),
+		get_registered_meta_keys( 'post', $post_type )
+	);
+
+	$wp_revisioned_meta_keys = array();
+
+	foreach ( $registered_meta as $name => $args ) {
+		if ( $args['revisions_enabled'] ) {
+			$wp_revisioned_meta_keys[ $name ] = true;
+		}
+	}
+
+	$wp_revisioned_meta_keys = array_keys( $wp_revisioned_meta_keys );
+
+	/**
+	 * Filter the list of post meta keys to be revisioned.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @param array  $keys      An array of meta fields to be revisioned.
+	 * @param string $post_type The post type being revisioned.
+	 */
+	return apply_filters( 'wp_post_revision_meta_keys', $wp_revisioned_meta_keys, $post_type );
+}
+
+/**
+ * Check whether revisioned post meta fields have changed.
+ *
+ * @since 6.4.0
+ *
+ * @param bool    $post_has_changed Whether the post has changed.
+ * @param WP_Post $last_revision    The last revision post object.
+ * @param WP_Post $post             The post object.
+ * @return bool Whether the post has changed.
+ */
+function wp_check_revisioned_meta_fields_have_changed( $post_has_changed, WP_Post $last_revision, WP_Post $post ) {
+	foreach ( wp_post_revision_meta_keys( $post->post_type ) as $meta_key ) {
+		if ( get_post_meta( $post->ID, $meta_key ) !== get_post_meta( $last_revision->ID, $meta_key ) ) {
+			$post_has_changed = true;
+			break;
+		}
+	}
+	return $post_has_changed;
+}
+
+/**
  * Deletes a revision.
  *
  * Deletes the row from the posts table corresponding to the specified revision.
  *
  * @since 2.6.0
  *
- * @param int|WP_Post $revision_id Revision ID or revision object.
+ * @param int|WP_Post $revision Revision ID or revision object.
  * @return WP_Post|false|null Null or false if error, deleted post object if success.
  */
-function wp_delete_post_revision( $revision_id ) {
-	$revision = wp_get_post_revision( $revision_id );
+function wp_delete_post_revision( $revision ) {
+	$revision = wp_get_post_revision( $revision );
+
 	if ( ! $revision ) {
 		return $revision;
 	}
 
 	$delete = wp_delete_post( $revision->ID );
+
 	if ( $delete ) {
 		/**
 		 * Fires once a post revision has been deleted.
@@ -478,12 +653,13 @@
  *
  * @see get_children()
  *
- * @param int|WP_Post $post_id Optional. Post ID or WP_Post object. Default is global `$post`.
- * @param array|null  $args    Optional. Arguments for retrieving post revisions. Default null.
- * @return array An array of revisions, or an empty array if none.
+ * @param int|WP_Post $post Optional. Post ID or WP_Post object. Default is global `$post`.
+ * @param array|null  $args Optional. Arguments for retrieving post revisions. Default null.
+ * @return WP_Post[]|int[] Array of revision objects or IDs, or an empty array if none.
  */
-function wp_get_post_revisions( $post_id = 0, $args = null ) {
-	$post = get_post( $post_id );
+function wp_get_post_revisions( $post = 0, $args = null ) {
+	$post = get_post( $post );
+
 	if ( ! $post || empty( $post->ID ) ) {
 		return array();
 	}
@@ -509,6 +685,7 @@
 	);
 
 	$revisions = get_children( $args );
+
 	if ( ! $revisions ) {
 		return array();
 	}
@@ -517,15 +694,67 @@
 }
 
 /**
+ * Returns the latest revision ID and count of revisions for a post.
+ *
+ * @since 6.1.0
+ *
+ * @param int|WP_Post $post Optional. Post ID or WP_Post object. Default is global $post.
+ * @return array|WP_Error {
+ *     Returns associative array with latest revision ID and total count,
+ *     or a WP_Error if the post does not exist or revisions are not enabled.
+ *
+ *     @type int $latest_id The latest revision post ID or 0 if no revisions exist.
+ *     @type int $count     The total count of revisions for the given post.
+ * }
+ */
+function wp_get_latest_revision_id_and_total_count( $post = 0 ) {
+	$post = get_post( $post );
+
+	if ( ! $post ) {
+		return new WP_Error( 'invalid_post', __( 'Invalid post.' ) );
+	}
+
+	if ( ! wp_revisions_enabled( $post ) ) {
+		return new WP_Error( 'revisions_not_enabled', __( 'Revisions not enabled.' ) );
+	}
+
+	$args = array(
+		'post_parent'         => $post->ID,
+		'fields'              => 'ids',
+		'post_type'           => 'revision',
+		'post_status'         => 'inherit',
+		'order'               => 'DESC',
+		'orderby'             => 'date ID',
+		'posts_per_page'      => 1,
+		'ignore_sticky_posts' => true,
+	);
+
+	$revision_query = new WP_Query();
+	$revisions      = $revision_query->query( $args );
+
+	if ( ! $revisions ) {
+		return array(
+			'latest_id' => 0,
+			'count'     => 0,
+		);
+	}
+
+	return array(
+		'latest_id' => $revisions[0],
+		'count'     => $revision_query->found_posts,
+	);
+}
+
+/**
  * Returns the url for viewing and potentially restoring revisions of a given post.
  *
  * @since 5.9.0
  *
- * @param int|WP_Post $post_id Optional. Post ID or WP_Post object. Default is global `$post`.
- * @return null|string The URL for editing revisions on the given post, otherwise null.
+ * @param int|WP_Post $post Optional. Post ID or WP_Post object. Default is global `$post`.
+ * @return string|null The URL for editing revisions on the given post, otherwise null.
  */
-function wp_get_post_revisions_url( $post_id = 0 ) {
-	$post = get_post( $post_id );
+function wp_get_post_revisions_url( $post = 0 ) {
+	$post = get_post( $post );
 
 	if ( ! $post instanceof WP_Post ) {
 		return null;
@@ -540,18 +769,17 @@
 		return null;
 	}
 
-	$revisions = wp_get_post_revisions( $post->ID, array( 'posts_per_page' => 1 ) );
+	$revisions = wp_get_latest_revision_id_and_total_count( $post->ID );
 
-	if ( 0 === count( $revisions ) ) {
+	if ( is_wp_error( $revisions ) || 0 === $revisions['count'] ) {
 		return null;
 	}
 
-	$revision = reset( $revisions );
-	return get_edit_post_link( $revision );
+	return get_edit_post_link( $revisions['latest_id'] );
 }
 
 /**
- * Determine if revisions are enabled for a given post.
+ * Determines whether revisions are enabled for a given post.
  *
  * @since 3.6.0
  *
@@ -563,7 +791,7 @@
 }
 
 /**
- * Determine how many revisions to retain for a given post.
+ * Determines how many revisions to retain for a given post.
  *
  * By default, an infinite number of revisions are kept.
  *
@@ -649,6 +877,7 @@
 
 	add_filter( 'get_the_terms', '_wp_preview_terms_filter', 10, 3 );
 	add_filter( 'get_post_metadata', '_wp_preview_post_thumbnail_filter', 10, 3 );
+	add_filter( 'get_post_metadata', '_wp_preview_meta_filter', 10, 4 );
 
 	return $post;
 }
@@ -684,11 +913,12 @@
  */
 function _wp_preview_terms_filter( $terms, $post_id, $taxonomy ) {
 	$post = get_post();
+
 	if ( ! $post ) {
 		return $terms;
 	}
 
-	if ( empty( $_REQUEST['post_format'] ) || $post->ID != $post_id
+	if ( empty( $_REQUEST['post_format'] ) || $post->ID !== $post_id
 		|| 'post_format' !== $taxonomy || 'revision' === $post->post_type
 	) {
 		return $terms;
@@ -698,6 +928,7 @@
 		$terms = array();
 	} else {
 		$term = get_term_by( 'slug', 'post-format-' . sanitize_key( $_REQUEST['post_format'] ), 'post_format' );
+
 		if ( $term ) {
 			$terms = array( $term ); // Can only have one post format.
 		}
@@ -719,21 +950,20 @@
  */
 function _wp_preview_post_thumbnail_filter( $value, $post_id, $meta_key ) {
 	$post = get_post();
+
 	if ( ! $post ) {
 		return $value;
 	}
 
-	if ( empty( $_REQUEST['_thumbnail_id'] ) ||
-		empty( $_REQUEST['preview_id'] ) ||
-		$post->ID != $post_id ||
-		'_thumbnail_id' !== $meta_key ||
-		'revision' === $post->post_type ||
-		$post_id != $_REQUEST['preview_id'] ) {
-
+	if ( empty( $_REQUEST['_thumbnail_id'] ) || empty( $_REQUEST['preview_id'] )
+		|| $post->ID !== $post_id || $post_id !== (int) $_REQUEST['preview_id']
+		|| '_thumbnail_id' !== $meta_key || 'revision' === $post->post_type
+	) {
 		return $value;
 	}
 
 	$thumbnail_id = (int) $_REQUEST['_thumbnail_id'];
+
 	if ( $thumbnail_id <= 0 ) {
 		return '';
 	}
@@ -765,16 +995,16 @@
 }
 
 /**
- * Upgrade the revisions author, add the current post as a revision and set the revisions version to 1
+ * Upgrades the revisions author, adds the current post as a revision and sets the revisions version to 1.
  *
  * @since 3.6.0
  * @access private
  *
  * @global wpdb $wpdb WordPress database abstraction object.
  *
- * @param WP_Post $post      Post object
- * @param array   $revisions Current revisions of the post
- * @return bool true if the revisions were upgraded, false if problems
+ * @param WP_Post $post      Post object.
+ * @param array   $revisions Current revisions of the post.
+ * @return bool true if the revisions were upgraded, false if problems.
  */
 function _wp_upgrade_revisions_of_post( $post, $revisions ) {
 	global $wpdb;
@@ -782,17 +1012,21 @@
 	// Add post option exclusively.
 	$lock   = "revision-upgrade-{$post->ID}";
 	$now    = time();
-	$result = $wpdb->query( $wpdb->prepare( "INSERT IGNORE INTO `$wpdb->options` (`option_name`, `option_value`, `autoload`) VALUES (%s, %s, 'no') /* LOCK */", $lock, $now ) );
+	$result = $wpdb->query( $wpdb->prepare( "INSERT IGNORE INTO `$wpdb->options` (`option_name`, `option_value`, `autoload`) VALUES (%s, %s, 'off') /* LOCK */", $lock, $now ) );
+
 	if ( ! $result ) {
 		// If we couldn't get a lock, see how old the previous lock is.
 		$locked = get_option( $lock );
+
 		if ( ! $locked ) {
-			// Can't write to the lock, and can't read the lock.
-			// Something broken has happened.
+			/*
+			 * Can't write to the lock, and can't read the lock.
+			 * Something broken has happened.
+			 */
 			return false;
 		}
 
-		if ( $locked > $now - 3600 ) {
+		if ( $locked > $now - HOUR_IN_SECONDS ) {
 			// Lock is not too old: some other process may be upgrading this post. Bail.
 			return false;
 		}
@@ -817,8 +1051,10 @@
 			continue;
 		}
 
-		// 1 is the latest revision version, so we're already up to date.
-		// No need to add a copy of the post as latest revision.
+		/*
+		 * 1 is the latest revision version, so we're already up to date.
+		 * No need to add a copy of the post as latest revision.
+		 */
 		if ( 0 < $this_revision_version ) {
 			$add_last = false;
 			continue;
@@ -860,3 +1096,38 @@
 
 	return true;
 }
+
+/**
+ * Filters preview post meta retrieval to get values from the autosave.
+ *
+ * Filters revisioned meta keys only.
+ *
+ * @since 6.4.0
+ *
+ * @param mixed  $value     Meta value to filter.
+ * @param int    $object_id Object ID.
+ * @param string $meta_key  Meta key to filter a value for.
+ * @param bool   $single    Whether to return a single value. Default false.
+ * @return mixed Original meta value if the meta key isn't revisioned, the object doesn't exist,
+ *               the post type is a revision or the post ID doesn't match the object ID.
+ *               Otherwise, the revisioned meta value is returned for the preview.
+ */
+function _wp_preview_meta_filter( $value, $object_id, $meta_key, $single ) {
+
+	$post = get_post();
+	if (
+		empty( $post ) ||
+		$post->ID !== $object_id ||
+		! in_array( $meta_key, wp_post_revision_meta_keys( $post->post_type ), true ) ||
+		'revision' === $post->post_type
+	) {
+		return $value;
+	}
+
+	$preview = wp_get_post_autosave( $post->ID );
+	if ( false === $preview ) {
+		return $value;
+	}
+
+	return get_post_meta( $preview->ID, $meta_key, $single );
+}