wordpress未能与站点联系致命错误，PHP修改被回滚

wordpress4.9.4后台修改php文件(添加或删除代码)时出现“未能与站点联系来检查致命错误，因此PHP修改已被回滚。您需要采用其他方式(如SFTP)上传您修改的PHP文件。”主要以下原因：

1、wordpress主题和版本程序不兼容问题，有的主题修改是正常的，有主题php修改出现异常。

2、wordpress版本更新的的一个BUG。

3、你添加的wordpress代码语法错误或代码冲突

WordPress 4.9 版本后台编辑主题PHP文件无法保存解决方法

1、通过ftp传送php文件到电脑本地用dreamweaver等编辑软件修改保存后，再上传。

2、打开wp-admin/includes/file.php文件，删除492-599行如下代码：

if ( $is_active && 'php' === $extension ) {

		$scrape_key = md5( rand() );
		$transient = 'scrape_key_' . $scrape_key;
		$scrape_nonce = strval( rand() );
		set_transient( $transient, $scrape_nonce, 60 ); // It shouldn't take more than 60 seconds to make the two loopback requests.

		$cookies = wp_unslash( $_COOKIE );
		$scrape_params = array(
			'wp_scrape_key' => $scrape_key,
			'wp_scrape_nonce' => $scrape_nonce,
		);
		$headers = array(
			'Cache-Control' => 'no-cache',
		);

		// Include Basic auth in loopback requests.
		if ( isset( $_SERVER['PHP_AUTH_USER'] ) && isset( $_SERVER['PHP_AUTH_PW'] ) ) {
			$headers['Authorization'] = 'Basic ' . base64_encode( wp_unslash( $_SERVER['PHP_AUTH_USER'] ) . ':' . wp_unslash( $_SERVER['PHP_AUTH_PW'] ) );
		}

		// Make sure PHP process doesn't die before loopback requests complete.
		@set_time_limit( 300 );

		// Time to wait for loopback requests to finish.
		$timeout = 100;

		$needle_start = "###### wp_scraping_result_start:$scrape_key ######";
		$needle_end = "###### wp_scraping_result_end:$scrape_key ######";

		// Attempt loopback request to editor to see if user just whitescreened themselves.
		if ( $plugin ) {
			$url = add_query_arg( compact( 'plugin', 'file' ), admin_url( 'plugin-editor.php' ) );
		} elseif ( isset( $stylesheet ) ) {
			$url = add_query_arg(
				array(
					'theme' => $stylesheet,
					'file' => $file,
				),
				admin_url( 'theme-editor.php' )
			);
		} else {
			$url = admin_url();
		}
		$url = add_query_arg( $scrape_params, $url );
		$r = wp_remote_get( $url, compact( 'cookies', 'headers', 'timeout' ) );
		$body = wp_remote_retrieve_body( $r );
		$scrape_result_position = strpos( $body, $needle_start );

		$loopback_request_failure = array(
			'code' => 'loopback_request_failed',
			'message' => __( 'Unable to communicate back with site to check for fatal errors, so the PHP change was reverted. You will need to upload your PHP file change by some other means, such as by using SFTP.' ),
		);
		$json_parse_failure = array(
			'code' => 'json_parse_error',
		);

		$result = null;
		if ( false === $scrape_result_position ) {
			$result = $loopback_request_failure;
		} else {
			$error_output = substr( $body, $scrape_result_position + strlen( $needle_start ) );
			$error_output = substr( $error_output, 0, strpos( $error_output, $needle_end ) );
			$result = json_decode( trim( $error_output ), true );
			if ( empty( $result ) ) {
				$result = $json_parse_failure;
			}
		}

		// Try making request to homepage as well to see if visitors have been whitescreened.
		if ( true === $result ) {
			$url = home_url( '/' );
			$url = add_query_arg( $scrape_params, $url );
			$r = wp_remote_get( $url, compact( 'cookies', 'headers', 'timeout' ) );
			$body = wp_remote_retrieve_body( $r );
			$scrape_result_position = strpos( $body, $needle_start );

			if ( false === $scrape_result_position ) {
				$result = $loopback_request_failure;
			} else {
				$error_output = substr( $body, $scrape_result_position + strlen( $needle_start ) );
				$error_output = substr( $error_output, 0, strpos( $error_output, $needle_end ) );
				$result = json_decode( trim( $error_output ), true );
				if ( empty( $result ) ) {
					$result = $json_parse_failure;
				}
			}
		}

		delete_transient( $transient );

		if ( true !== $result ) {

			// Roll-back file change.
			file_put_contents( $real_file, $previous_content );
			if ( function_exists( 'opcache_invalidate' ) ) {
				opcache_invalidate( $real_file, true );
			}

			if ( ! isset( $result['message'] ) ) {
				$message = __( 'An unidentified error has occurred.' );
			} else {
				$message = $result['message'];
				unset( $result['message'] );
			}
			return new WP_Error( 'php_error', $message, $result );
		}
	}

这个方法仅仅是WordPress官方出更新前的一个临时替代方式，永久的解决还是等官方修复。

3、等待官方(https://cn.wordpress.org/download/bug)修复，目前wordpress简体中文版最新为WordPress 4.9.4。