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* Upgrade API: Core_Upgrader class
* Core class used for updating core.
* It allows for WordPress to upgrade itself in combination with
* the wp-admin/includes/update-core.php file.
* @since 4.6.0 Moved to its own file from wp-admin/includes/class-wp-upgrader.php.
class Core_Upgrader extends WP_Upgrader {
* Initializes the upgrade strings.
public function upgrade_strings() {
$this->strings['up_to_date'] = __( 'WordPress is at the latest version.' );
$this->strings['locked'] = __( 'Another update is currently in progress.' );
$this->strings['no_package'] = __( 'Update package not available.' );
/* translators: %s: Package URL. */
$this->strings['downloading_package'] = sprintf( __( 'Downloading update from %s…' ), '<span class="code pre">%s</span>' );
$this->strings['unpack_package'] = __( 'Unpacking the update…' );
$this->strings['copy_failed'] = __( 'Could not copy files.' );
$this->strings['copy_failed_space'] = __( 'Could not copy files. You may have run out of disk space.' );
$this->strings['start_rollback'] = __( 'Attempting to restore the previous version.' );
$this->strings['rollback_was_required'] = __( 'Due to an error during updating, WordPress has been restored to your previous version.' );
* Upgrades WordPress core.
* @global WP_Filesystem_Base $wp_filesystem WordPress filesystem subclass.
* @global callable $_wp_filesystem_direct_method
* @param object $current Response object for whether WordPress is current.
* Optional. Arguments for upgrading WordPress core. Default empty array.
* @type bool $pre_check_md5 Whether to check the file checksums before
* attempting the upgrade. Default true.
* @type bool $attempt_rollback Whether to attempt to rollback the chances if
* there is a problem. Default false.
* @type bool $do_rollback Whether to perform this "upgrade" as a rollback.
* @return string|false|WP_Error New WordPress version on success, false or WP_Error on failure.
public function upgrade( $current, $args = array() ) {
require ABSPATH . WPINC . '/version.php'; // $wp_version;
'attempt_rollback' => false,
'allow_relaxed_file_ownership' => false,
$parsed_args = wp_parse_args( $args, $defaults );
$this->upgrade_strings();
// Is an update available?
if ( ! isset( $current->response ) || 'latest' === $current->response ) {
return new WP_Error( 'up_to_date', $this->strings['up_to_date'] );
$res = $this->fs_connect( array( ABSPATH, WP_CONTENT_DIR ), $parsed_args['allow_relaxed_file_ownership'] );
if ( ! $res || is_wp_error( $res ) ) {
$wp_dir = trailingslashit( $wp_filesystem->abspath() );
if ( $parsed_args['do_rollback'] ) {
} elseif ( $parsed_args['pre_check_md5'] && ! $this->check_files() ) {
* If partial update is returned from the API, use that, unless we're doing
* a reinstallation. If we cross the new_bundled version number, then use
* the new_bundled zip. Don't though if the constant is set to skip bundled items.
* If the API returns a no_content zip, go with it. Finally, default to the full zip.
if ( $parsed_args['do_rollback'] && $current->packages->rollback ) {
$to_download = 'rollback';
} elseif ( $current->packages->partial && 'reinstall' !== $current->response && $wp_version === $current->partial_version && $partial ) {
$to_download = 'partial';
} elseif ( $current->packages->new_bundled && version_compare( $wp_version, $current->new_bundled, '<' )
&& ( ! defined( 'CORE_UPGRADE_SKIP_NEW_BUNDLED' ) || ! CORE_UPGRADE_SKIP_NEW_BUNDLED ) ) {
$to_download = 'new_bundled';
} elseif ( $current->packages->no_content ) {
$to_download = 'no_content';
// Lock to prevent multiple Core Updates occurring.
$lock = WP_Upgrader::create_lock( 'core_updater', 15 * MINUTE_IN_SECONDS );
return new WP_Error( 'locked', $this->strings['locked'] );
$download = $this->download_package( $current->packages->$to_download, false );
* Allow for signature soft-fail.
* WARNING: This may be removed in the future.
if ( is_wp_error( $download ) && $download->get_error_data( 'softfail-filename' ) ) {
// Output the failure error as a normal feedback, and not as an error:
/** This filter is documented in wp-admin/includes/update-core.php */
apply_filters( 'update_feedback', $download->get_error_message() );
// Report this failure back to WordPress.org for debugging purposes.
'signature_failure_code' => $download->get_error_code(),
'signature_failure_data' => $download->get_error_data(),
// Pretend this error didn't happen.
$download = $download->get_error_data( 'softfail-filename' );
if ( is_wp_error( $download ) ) {
WP_Upgrader::release_lock( 'core_updater' );
$working_dir = $this->unpack_package( $download );
if ( is_wp_error( $working_dir ) ) {
WP_Upgrader::release_lock( 'core_updater' );
// Copy update-core.php from the new version into place.
if ( ! $wp_filesystem->copy( $working_dir . '/wordpress/wp-admin/includes/update-core.php', $wp_dir . 'wp-admin/includes/update-core.php', true ) ) {
$wp_filesystem->delete( $working_dir, true );
WP_Upgrader::release_lock( 'core_updater' );
return new WP_Error( 'copy_failed_for_update_core_file', __( 'The update cannot be installed because some files could not be copied. This is usually due to inconsistent file permissions.' ), 'wp-admin/includes/update-core.php' );
$wp_filesystem->chmod( $wp_dir . 'wp-admin/includes/update-core.php', FS_CHMOD_FILE );
wp_opcache_invalidate( ABSPATH . 'wp-admin/includes/update-core.php' );
require_once ABSPATH . 'wp-admin/includes/update-core.php';
if ( ! function_exists( 'update_core' ) ) {
WP_Upgrader::release_lock( 'core_updater' );
return new WP_Error( 'copy_failed_space', $this->strings['copy_failed_space'] );
$result = update_core( $working_dir, $wp_dir );
// In the event of an issue, we may be able to roll back.
if ( $parsed_args['attempt_rollback'] && $current->packages->rollback && ! $parsed_args['do_rollback'] ) {
if ( is_wp_error( $result ) ) {
$error_code = $result->get_error_code();
* Not all errors are equal. These codes are critical: copy_failed__copy_dir,
* mkdir_failed__copy_dir, copy_failed__copy_dir_retry, and disk_full.
* do_rollback allows for update_core() to trigger a rollback if needed.
if ( str_contains( $error_code, 'do_rollback' ) ) {
} elseif ( str_contains( $error_code, '__copy_dir' ) ) {
} elseif ( 'disk_full' === $error_code ) {
/** This filter is documented in wp-admin/includes/update-core.php */
apply_filters( 'update_feedback', $result );
/** This filter is documented in wp-admin/includes/update-core.php */
apply_filters( 'update_feedback', $this->strings['start_rollback'] );
$rollback_result = $this->upgrade( $current, array_merge( $parsed_args, array( 'do_rollback' => true ) ) );
$original_result = $result;
$this->strings['rollback_was_required'],
'update' => $original_result,
'rollback' => $rollback_result,
/** This action is documented in wp-admin/includes/class-wp-upgrader.php */
'upgrader_process_complete',
// Clear the current updates.
delete_site_transient( 'update_core' );
if ( ! $parsed_args['do_rollback'] ) {
'update_type' => $current->response,
'fs_method' => $wp_filesystem->method,
'fs_method_forced' => defined( 'FS_METHOD' ) || has_filter( 'filesystem_method' ),
'fs_method_direct' => ! empty( $GLOBALS['_wp_filesystem_direct_method'] ) ? $GLOBALS['_wp_filesystem_direct_method'] : '',
'time_taken' => time() - $start_time,
'reported' => $wp_version,
'attempted' => $current->version,
if ( is_wp_error( $result ) ) {
$stats['success'] = false;
if ( ! empty( $try_rollback ) ) {
$stats['error_code'] = $original_result->get_error_code();
$stats['error_data'] = $original_result->get_error_data();
// Was the rollback successful? If not, collect its error too.
$stats['rollback'] = ! is_wp_error( $rollback_result );
if ( is_wp_error( $rollback_result ) ) {
$stats['rollback_code'] = $rollback_result->get_error_code();
$stats['rollback_data'] = $rollback_result->get_error_data();
$stats['error_code'] = $result->get_error_code();
$stats['error_data'] = $result->get_error_data();
wp_version_check( $stats );
WP_Upgrader::release_lock( 'core_updater' );
* Determines if this WordPress Core version should update to an offered version or not.
* @param string $offered_ver The offered version, of the format x.y.z.
* @return bool True if we should update to the offered version, otherwise false.
public static function should_update_to_version( $offered_ver ) {
require ABSPATH . WPINC . '/version.php'; // $wp_version; // x.y.z
$current_branch = implode( '.', array_slice( preg_split( '/[.-]/', $wp_version ), 0, 2 ) ); // x.y
$new_branch = implode( '.', array_slice( preg_split( '/[.-]/', $offered_ver ), 0, 2 ) ); // x.y
$current_is_development_version = (bool) strpos( $wp_version, '-' );
$upgrade_dev = get_site_option( 'auto_update_core_dev', 'enabled' ) === 'enabled';
$upgrade_minor = get_site_option( 'auto_update_core_minor', 'enabled' ) === 'enabled';
$upgrade_major = get_site_option( 'auto_update_core_major', 'unset' ) === 'enabled';
// WP_AUTO_UPDATE_CORE = true (all), 'beta', 'rc', 'development', 'branch-development', 'minor', false.
if ( defined( 'WP_AUTO_UPDATE_CORE' ) ) {
if ( false === WP_AUTO_UPDATE_CORE ) {
// Defaults to turned off, unless a filter allows it.
} elseif ( true === WP_AUTO_UPDATE_CORE
|| in_array( WP_AUTO_UPDATE_CORE, array( 'beta', 'rc', 'development', 'branch-development' ), true )
} elseif ( 'minor' === WP_AUTO_UPDATE_CORE ) {
// Only minor updates for core.
// 1: If we're already on that version, not much point in updating?
if ( $offered_ver === $wp_version ) {
// 2: If we're running a newer version, that's a nope.
if ( version_compare( $wp_version, $offered_ver, '>' ) ) {
$failure_data = get_site_option( 'auto_core_update_failed' );
// If this was a critical update failure, cannot update.
if ( ! empty( $failure_data['critical'] ) ) {
// Don't claim we can update on update-core.php if we have a non-critical failure logged.
if ( $wp_version === $failure_data['current'] && str_contains( $offered_ver, '.1.next.minor' ) ) {
* Cannot update if we're retrying the same A to B update that caused a non-critical failure.
* Some non-critical failures do allow retries, like download_failed.
* 3.7.1 => 3.7.2 resulted in files_not_writable, if we are still on 3.7.1 and still trying to update to 3.7.2.
if ( empty( $failure_data['retry'] ) && $wp_version === $failure_data['current'] && $offered_ver === $failure_data['attempted'] ) {
// 3: 3.7-alpha-25000 -> 3.7-alpha-25678 -> 3.7-beta1 -> 3.7-beta2.
if ( $current_is_development_version ) {
* Filters whether to enable automatic core updates for development versions.
* @param bool $upgrade_dev Whether to enable automatic updates for
if ( ! apply_filters( 'allow_dev_auto_core_updates', $upgrade_dev ) ) {
// Else fall through to minor + major branches below.
// 4: Minor in-branch updates (3.7.0 -> 3.7.1 -> 3.7.2 -> 3.7.4).
if ( $current_branch === $new_branch ) {
* Filters whether to enable minor automatic core updates.
* @param bool $upgrade_minor Whether to enable minor automatic core updates.
return apply_filters( 'allow_minor_auto_core_updates', $upgrade_minor );
// 5: Major version updates (3.7.0 -> 3.8.0 -> 3.9.1).
if ( version_compare( $new_branch, $current_branch, '>' ) ) {
* Filters whether to enable major automatic core updates.
* @param bool $upgrade_major Whether to enable major automatic core updates.
return apply_filters( 'allow_major_auto_core_updates', $upgrade_major );
// If we're not sure, we don't want it.
* Compares the disk file checksums against the expected checksums.
* @global string $wp_version The WordPress version string.
* @global string $wp_local_package Locale code of the package.
* @return bool True if the checksums match, otherwise false.
public function check_files() {
global $wp_version, $wp_local_package;
$checksums = get_core_checksums( $wp_version, isset( $wp_local_package ) ? $wp_local_package : 'en_US' );
if ( ! is_array( $checksums ) ) {
foreach ( $checksums as $file => $checksum ) {
// Skip files which get updated.
if ( str_starts_with( $file, 'wp-content' ) ) {
if ( ! file_exists( ABSPATH . $file ) || md5_file( ABSPATH . $file ) !== $checksum ) {
It is recommended that you Edit text format, this type of Fix handles quite a lot in one request
