Use reserved prefix for internal transaction savepoint names

Author: JanJakes

wp-includes/sqlite-ast/class-wp-sqlite-driver.php

@@ -812,7 +812,8 @@ public function begin_transaction(): void {
 			 */
 			$this->execute_sqlite_query( $this->is_readonly ? 'BEGIN' : 'BEGIN IMMEDIATE' );
 		} else {
-			$this->execute_sqlite_query( 'SAVEPOINT LEVEL' . $this->transaction_level );
+			$savepoint_name = $this->get_internal_savepoint_name( $this->transaction_level );
+			$this->execute_sqlite_query( sprintf( 'SAVEPOINT %s', $savepoint_name ) );
 		}
 		++$this->transaction_level;
 	}
@@ -829,7 +830,8 @@ public function commit(): void {
 		if ( 0 === $this->transaction_level ) {
 			$this->execute_sqlite_query( 'COMMIT' );
 		} else {
-			$this->execute_sqlite_query( 'RELEASE SAVEPOINT LEVEL' . $this->transaction_level );
+			$savepoint_name = $this->get_internal_savepoint_name( $this->transaction_level );
+			$this->execute_sqlite_query( sprintf( 'RELEASE SAVEPOINT %s', $savepoint_name ) );
 		}
 	}
 
@@ -845,7 +847,8 @@ public function rollback(): void {
 		if ( 0 === $this->transaction_level ) {
 			$this->execute_sqlite_query( 'ROLLBACK' );
 		} else {
-			$this->execute_sqlite_query( 'ROLLBACK TO SAVEPOINT LEVEL' . $this->transaction_level );
+			$savepoint_name = $this->get_internal_savepoint_name( $this->transaction_level );
+			$this->execute_sqlite_query( sprintf( 'ROLLBACK TO SAVEPOINT %s', $savepoint_name ) );
 		}
 	}
 
@@ -4109,6 +4112,19 @@ private function get_sqlite_index_name( string $mysql_table_name, string $mysql_
 		return $mysql_table_name . '__' . $mysql_index_name;
 	}
 
+	/**
+	 * Get an internal savepoint name.
+	 *
+	 * Internal savepoints are used to emulate MySQL transactions that are run
+	 * inside a wrapping SQLite transaction, as transactions can't be nested.
+	 *
+	 * @param  int $level The transaction nesting level.
+	 * @return string     The internal savepoint name.
+	 */
+	private function get_internal_savepoint_name( int $level ): string {
+		return sprintf( '%ssavepoint_%d', self::RESERVED_PREFIX, $level );
+	}
+
 	/**
 	 * Get an SQLite query to emulate MySQL "ON UPDATE CURRENT_TIMESTAMP".
 	 *