rdbms: clean up and simplify toString() handle for Database

Change-Id: Ia95e25505785aad71b70a74f4ec7a07a73e419e1

6 files changed, 40 insertions, 30 deletions

diff --git a/includes/libs/rdbms/database/DBConnRef.php b/includes/libs/rdbms/database/DBConnRef.php
index b21689248618..841a7ba40a75 100644
--- a/includes/libs/rdbms/database/DBConnRef.php
+++ b/includes/libs/rdbms/database/DBConnRef.php
@@ -740,6 +740,19 @@ class DBConnRef implements IDatabase {
 		return $this->__call( __FUNCTION__, func_get_args() );
 	}
 
+	public function __toString() {
+		if ( $this->conn === null ) {
+			// spl_object_id is PHP >= 7.2
+			$id = function_exists( 'spl_object_id' )
+				? spl_object_id( $this )
+				: spl_object_hash( $this );
+
+			return $this->getType() . ' object #' . $id;
+		}
+
+		return $this->__call( __FUNCTION__, func_get_args() );
+	}
+
 	/**
 	 * Error out if the role is not DB_MASTER
 	 *
diff --git a/includes/libs/rdbms/database/Database.php b/includes/libs/rdbms/database/Database.php
index c6b166200723..b7b45bdc85eb 100644
--- a/includes/libs/rdbms/database/Database.php
+++ b/includes/libs/rdbms/database/Database.php
@@ -4666,12 +4666,24 @@ abstract class Database implements IDatabase, IMaintainableDatabase, LoggerAware
 		return $this->conn;
 	}
 
-	/**
-	 * @since 1.19
-	 * @return string
-	 */
 	public function __toString() {
-		return (string)$this->conn;
+		// spl_object_id is PHP >= 7.2
+		$id = function_exists( 'spl_object_id' )
+			? spl_object_id( $this )
+			: spl_object_hash( $this );
+
+		$description = $this->getType() . ' object #' . $id;
+		if ( is_resource( $this->conn ) ) {
+			$description .= ' (' . (string)$this->conn . ')'; // "resource id #<ID>"
+		} elseif ( is_object( $this->conn ) ) {
+			// spl_object_id is PHP >= 7.2
+			$handleId = function_exists( 'spl_object_id' )
+				? spl_object_id( $this->conn )
+				: spl_object_hash( $this->conn );
+			$description .= " (handle id #$handleId)";
+		}
+
+		return $description;
 	}
 
 	/**
diff --git a/includes/libs/rdbms/database/DatabaseMysqli.php b/includes/libs/rdbms/database/DatabaseMysqli.php
index 1a5cdab78dad..937f381ac14d 100644
--- a/includes/libs/rdbms/database/DatabaseMysqli.php
+++ b/includes/libs/rdbms/database/DatabaseMysqli.php
@@ -308,21 +308,6 @@ class DatabaseMysqli extends DatabaseMysqlBase {
 	}
 
 	/**
-	 * Give an id for the connection
-	 *
-	 * mysql driver used resource id, but mysqli objects cannot be cast to string.
-	 * @return string
-	 */
-	public function __toString() {
-		if ( $this->conn instanceof mysqli ) {
-			return (string)$this->conn->thread_id;
-		} else {
-			// mConn might be false or something.
-			return (string)$this->conn;
-		}
-	}
-
-	/**
 	 * @return mysqli
 	 */
 	protected function getBindingHandle() {
diff --git a/includes/libs/rdbms/database/DatabaseSqlite.php b/includes/libs/rdbms/database/DatabaseSqlite.php
index 3722ef430bc6..dcc7c46c3aa6 100644
--- a/includes/libs/rdbms/database/DatabaseSqlite.php
+++ b/includes/libs/rdbms/database/DatabaseSqlite.php
@@ -1120,15 +1120,6 @@ class DatabaseSqlite extends Database {
 	}
 
 	/**
-	 * @return string
-	 */
-	public function __toString() {
-		return is_object( $this->conn )
-			? 'SQLite ' . (string)$this->conn->getAttribute( PDO::ATTR_SERVER_VERSION )
-			: '(not connected)';
-	}
-
-	/**
 	 * @return PDO
 	 */
 	protected function getBindingHandle() {
diff --git a/includes/libs/rdbms/database/IDatabase.php b/includes/libs/rdbms/database/IDatabase.php
index 89a66e82d094..802af15c5bf8 100644
--- a/includes/libs/rdbms/database/IDatabase.php
+++ b/includes/libs/rdbms/database/IDatabase.php
@@ -2199,6 +2199,15 @@ interface IDatabase {
 	 * @since 1.31
 	 */
 	public function setIndexAliases( array $aliases );
+
+	/**
+	 * Get a debugging string that mentions the database type, the ID of this instance,
+	 * and the ID of any underlying connection resource or driver object if one is present
+	 *
+	 * @return string "<db type> object #<X>" or "<db type> object #<X> (resource/handle id #<Y>)"
+	 * @since 1.34
+	 */
+	public function __toString();
 }
 
 /**
diff --git a/tests/phpunit/includes/db/DatabaseSqliteTest.php b/tests/phpunit/includes/db/DatabaseSqliteTest.php
index 857988c8992c..0f5c1f2f7f4c 100644
--- a/tests/phpunit/includes/db/DatabaseSqliteTest.php
+++ b/tests/phpunit/includes/db/DatabaseSqliteTest.php
@@ -540,7 +540,7 @@ class DatabaseSqliteTest extends MediaWikiTestCase {
 
 		$toString = (string)$db;
 
-		$this->assertContains( 'SQLite ', $toString );
+		$this->assertContains( 'sqlite object', $toString );
 	}
 
 	/**