diff --git a/src/main.go b/src/main.go
index dfaa51a..5e09363 100644
--- a/src/main.go
+++ b/src/main.go
@@ -51,6 +51,9 @@ var (
 )
 
 func init() {
+	// Disable the `--source` command by default to avoid breaking existing tests
+	disableSource = true
+
 	flag.StringVar(&host, "host", "127.0.0.1", "The host of the TiDB/MySQL server.")
 	flag.StringVar(&port, "port", "4000", "The listen port of TiDB/MySQL server.")
 	flag.StringVar(&user, "user", "root", "The user for connecting to the database.")
@@ -523,7 +526,7 @@ func (t *tester) runQueries(queries []query) (int, error) {
 			disableSource = true
 		case Q_SOURCE:
 			if disableSource {
-				log.WithFields(log.Fields{"line": q.location()}).Warn("source command disabled")
+				log.WithFields(log.Fields{"line": q.location()}).Warn("source command disabled, add '--enable_source' to your file to enable")
 				break
 			}
 			fileName := strings.TrimSpace(q.Query)
diff --git a/t/source.test b/t/source.test
index 05b440d..05140a3 100644
--- a/t/source.test
+++ b/t/source.test
@@ -1,3 +1,5 @@
+--enable_source
+
 --echo before source
 --source include/hello1.inc
 --echo after source