Add a debug helper coverage logger module.

projects/plugins/debug-helper/.gitignore

@@ -1 +1,2 @@
 /vendor/
+/scripts/wp-config.php

projects/plugins/debug-helper/changelog/add-debug-helper-coverage-logger

@@ -0,0 +1,4 @@
+Significance: minor
+Type: added
+
+Added a new module for coverage data logging.

projects/plugins/debug-helper/modules/class-coverage-logger.php

@@ -0,0 +1,132 @@
+<?php
+/**
+ * The Coverage Logger file contains the class `Coverage_Logger` that logs coverage data.
+ *
+ * @package automattic/jetpack-debug-helper
+ */
+
+namespace Automattic\Jetpack\Debug_Helper;
+
+/**
+ * Class Coverage_Logger
+ *
+ * Handles logging of coverage data that Jetpack plugins generate.
+ *
+ * @package Automattic\Jetpack\Debug_Helper
+ */
+class Coverage_Logger {
+
+	const RUNTIME_TABLE_NAME = 'jetpack_runtime_coverage_data';
+
+	/**
+	 * XMLRPC_Logger constructor.
+	 * Hooks the XML-RPC logging function into WordPress's init action.
+	 */
+	public function __construct() {
+		if ( function_exists( 'xdebug_start_code_coverage' ) ) {
+			$this->maybe_upsert_database();
+
+			xdebug_start_code_coverage();
+			add_action( 'shutdown', array( $this, 'log_coverage_results' ), 100000 );
+		}
+	}
+
+	/**
+	 * Saves coverage results into a file.
+	 */
+	public function log_coverage_results() {
+		global $wpdb;
+
+		$coverage_data = xdebug_get_code_coverage();
+
+		$sql = sprintf( 'INSERT IGNORE INTO `%s` (path, line) VALUES ', $wpdb->prefix . self::RUNTIME_TABLE_NAME );
+
+		foreach ( $coverage_data as $file => $lines ) {
+			$path = substr( $file, strlen( ABSPATH ) );
+
+			if ( ! str_starts_with( $path, 'wp-content/plugins/jetpack' ) ) {
+				continue;
+			}
+
+			if ( false !== strpos( $path, '/vendor/' ) ) {
+				continue;
+			}
+
+			$path = substr( $path, strlen( 'wp-content/plugins/' ) );
+
+			$vendor_pos = strpos( $path, 'jetpack_vendor' );
+			if ( false !== $vendor_pos ) {
+				$path = substr( $path, $vendor_pos + strlen( 'jetpack_vendor/automattic/' ) );
+			}
+
+			foreach ( $lines as $line => $count ) {
+				for ( $i = 0; $i < $count; $i++ ) {
+					$sql .= $wpdb->prepare( '( %s, %d ),', $path, $line );
+				}
+			}
+		}
+
+		$wpdb->query( rtrim( $sql, ',' ) ); // phpcs:ignore WordPress.DB -- We are preparing the query before this.
+	}
+
+	/**
+	 * Uses the dbDelta function to either update, create, or leave the existing
+	 * database in peace.
+	 */
+	protected function maybe_upsert_database() {
+		global $wpdb;
+
+		$charset_collate = $wpdb->get_charset_collate();
+		$table_name      = $wpdb->prefix . self::RUNTIME_TABLE_NAME;
+
+		$sql = array(
+			"CREATE TABLE $table_name (
+  id mediumint(9) NOT NULL AUTO_INCREMENT,
+  path varchar(255),
+  line int,
+  PRIMARY KEY (id),
+  UNIQUE KEY `unique_path` (path, line)
+) $charset_collate;",
+		);
+
+		require_once ABSPATH . 'wp-admin/includes/upgrade.php';
+		dbDelta( $sql );
+	}
+
+	/**
+	 * Returns an SQL string for getting the coverage diff results.
+	 */
+	protected function get_coverage_diff() {
+		return '
+SELECT
+    runtime.path AS file_path,
+    runtime.lines_covered AS runtime_coverage,
+    test.line AS test_coverage,
+    runtime.lines_covered - test.line AS coverage_difference
+        FROM
+    (
+        SELECT
+            path,
+            COUNT(DISTINCT line) AS lines_covered
+        FROM
+            wp_jetpack_runtime_coverage_data
+        GROUP BY
+            path
+    ) AS runtime
+    INNER JOIN
+    (
+        SELECT
+            path,
+            line
+        FROM
+            wp_jetpack_test_coverage_data
+    ) AS test
+    ON runtime.path = test.path
+    ORDER BY coverage_difference
+';
+	}
+}
+
+if ( isset( $_COOKIE['jetpack_enable_coverage_logging'] ) ) {
+	new Coverage_Logger();
+}

projects/plugins/debug-helper/plugin.php

@@ -114,6 +114,11 @@
 		'name'        => 'XMLRPC Logger',
 		'description' => 'Logs incoming XMLRPC requests into the debug.log file.',
 	),
+	'coverage-logger'           => array(
+		'file'        => 'class-coverage-logger.php',
+		'name'        => 'Coverage Logger',
+		'description' => 'Logs coverage data.',
+	),
 	'xmlrpc-blocker'            => array(
 		'file'        => 'class-xmlrpc-blocker.php',
 		'name'        => 'Broken XML-RPC',

projects/plugins/debug-helper/scripts/load-coverage-data.php

@@ -0,0 +1,86 @@
+<?php // phpcs:ignore Squiz.Commenting
+// phpcs:disable WordPress.DB
+
+if ( ! file_exists( __DIR__ . '/wp-config.php' ) ) {
+	echo 'This script needs a WordPress config file for database configuration to work.' . PHP_EOL;
+	echo 'You can copy your WordPress configuration part where it defines database connection and table prefix.' . PHP_EOL;
+	echo 'Put them in a wp-config.php file in this folder, just don\'t forget to remove it when you\'re done.' . PHP_EOL;
+	exit( 1 );
+}
+
+require_once __DIR__ . '/wp-config.php';
+
+$data  = get_coverage_data();
+$table = $table_prefix . 'jetpack_test_coverage_data'; // phpcs:ignore VariableAnalysis -- required from wp-config.php
+
+mysqli_report( MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT );
+$dbh = new mysqli( DB_HOST, DB_USER, DB_PASSWORD, DB_NAME );
+
+$create_table = sprintf(
+	'CREATE TABLE IF NOT EXISTS `%s` (
+ id int NOT NULL AUTO_INCREMENT,
+ path varchar(255),
+ line int,
+ PRIMARY KEY (id),
+ UNIQUE KEY `unique_path` (path, line)
+ )',
+	$table
+);
+
+$dbh->query( $create_table );
+
+$sql = sprintf( 'INSERT IGNORE INTO `%s` (path, line) VALUES ', $table );
+
+foreach ( $data as $file ) {
+	$sql .= sprintf( "( '%s', %d ),", $file['file'], $file['lines'] );
+}
+
+$dbh->query( rtrim( $sql, ',' ) ); // phpcs:ignore WordPress.DB -- We are preparing the query before this.
+
+$dbh->close();
+
+/**
+ * Returns an unserialized coverage object.
+ *
+ * @return Array coverage data
+ */
+function get_coverage_data() {
+
+	$coverage = array();
+
+	try {
+		$file = new SplFileObject( 'summary.tsv' );
+	} catch ( LogicException $exception ) {
+		die( 'SplFileObject : ' . $exception->getMessage() ); // phpcs:ignore WordPress.Security
+	}
+
+	while ( $file->valid() ) {
+		$line = $file->fgets();
+
+		list( $filename, $executable, $executed ) = explode( "\t", $line ); // phpcs:ignore VariableAnalysis
+
+		if ( str_starts_with( $filename, 'projects/js-packages' ) ) {
+			continue;
+		}
+
+		if (
+			str_starts_with( $filename, 'projects/packages' )
+		) {
+			$filename = 'jetpack-' . substr( $filename, strlen( 'projects/packages/' ) );
+		}
+
+		if ( str_starts_with( $filename, 'projects/plugins/jetpack/' ) ) {
+			$filename = substr( $filename, strlen( 'projects/plugins/' ) );
+		} elseif ( str_starts_with( $filename, 'projects/plugins' ) ) {
+			$filename = 'jetpack-' . substr( $filename, strlen( 'projects/plugins/' ) );
+		}
+
+		$coverage[] = array(
+			'file'  => $filename,
+			'lines' => $executed,
+		);
+	}
+
+	$file = null;
+	return $coverage;
+}