wp-admin/includes/update-core.php:1093Upgrades the core of WordPress.
$fromstring$tostringstring|WP_Error7 hooks fire while update_core() runs, in this order:
Filters feedback messages displayed during the core update process.
Filters feedback messages displayed during the core update process.
Filters feedback messages displayed during the core update process.
Filters feedback messages displayed during the core update process.
Filters feedback messages displayed during the core update process.
Filters feedback messages displayed during the core update process.
Fires after WordPress core has been successfully updated.
function update_core( $from, $to ) { global $wp_filesystem, $_old_files, $_old_requests_files, $_new_bundled_files, $wpdb; /* * Give core update script an additional 300 seconds (5 minutes) * to finish updating large files when running on slower servers. */ if ( function_exists( 'set_time_limit' ) ) { set_time_limit( 300 ); } /* * Merge the old Requests files and directories into the `$_old_files`. * Then preload these Requests files first, before the files are deleted * and replaced to ensure the code is in memory if needed. */ $_old_files = array_merge( $_old_files, array_values( $_old_requests_files ) ); _preload_old_requests_classes_and_interfaces( $to ); /** * Filters feedback messages displayed during the core update process. * * The filter is first evaluated after the zip file for the latest version * has been downloaded and unzipped. It is evaluated five more times during * the process: * * 1. Before WordPress begins the core upgrade process. * 2. Before Maintenance Mode is enabled. * 3. Before WordPress begins copying over the necessary files. * 4. Before Maintenance Mode is disabled. * 5. Before the database is upgraded. * * @since 2.5.0 * * @param string $feedback The core update feedback messages. */ apply_filters( 'update_feedback', __( 'Verifying the unpacked files…' ) ); // Confidence check the unzipped distribution. $distro = ''; $roots = array( '/wordpress/', '/wordpress-mu/' ); foreach ( $roots as $root ) { if ( $wp_filesystem->exists( $from . $root . 'readme.html' ) && $wp_filesystem->exists( $from . $root . 'wp-includes/version.php' ) ) { $distro = $root; break; } } if ( ! $distro ) { $wp_filesystem->delete( $from, true ); return new WP_Error( 'insane_distro', __( 'The update could not be unpacked' ) ); } /* * Import $wp_version, $required_php_version, $required_php_extensions, and $required_mysql_version from the new version. * DO NOT globalize any variables imported from `version-current.php` in this function. * * BC Note: $wp_filesystem->wp_content_dir() returned unslashed pre-2.8. */ $versions_file = trailingslashit( $wp_filesystem->wp_content_dir() ) . 'upgrade/version-current.php'; if ( ! $wp_filesystem->copy( $from . $distro . 'wp-includes/version.php', $versions_file ) ) { $wp_filesystem->delete( $from, true ); return new WP_Error( 'copy_failed_for_version_file', __( 'The update cannot be installed because some files could not be copied. This is usually due to inconsistent file permissions.' ), 'wp-includes/version.php' ); } $wp_filesystem->chmod( $versions_file, FS_CHMOD_FILE ); /* * `wp_opcache_invalidate()` only exists in WordPress 5.5 or later, * so don't run it when upgrading from older versions.Introduced in 2.7.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-admin/includes/update-core.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.