Bug fix for db.Ping(ctx) against a Doltgres server

Author: fulghum

postgres/parser/parser/sql/sql_parser.go

@@ -56,7 +56,7 @@ func (p *PostgresParser) ParseWithOptions(ctx context.Context, query string, del
 		return nil, "", "", fmt.Errorf("only a single statement at a time is currently supported")
 	}
 	if len(stmts) == 0 {
-		return nil, q, "", nil
+		return nil, q, "", vitess.ErrEmpty
 	}
 
 	vitessAST, err := ast.Convert(stmts[0])

testing/go/framework.go

@@ -130,6 +130,7 @@ func RunScript(t *testing.T, script ScriptTest, normalizeRows bool) {
 			Default: pgxConn,
 			Current: pgxConn,
 		}
+		require.NoError(t, pgxConn.Ping(ctx))
 		defer func() {
 			conn.Close(ctx)
 		}()
@@ -309,6 +310,9 @@ func CreateServer(t *testing.T, database string) (context.Context, *Connection,
 
 	conn, err := pgx.Connect(ctx, fmt.Sprintf("postgres://postgres:[email protected]:%d/%s", port, database))
 	require.NoError(t, err)
+
+	// Ping the connection to test that it's alive, and also to test that Doltgres handles empty queries correctly
+	require.NoError(t, conn.Ping(ctx))
 	return ctx, &Connection{
 		Default: conn,
 		Current: conn,

testing/go/smoke_test.go

@@ -71,6 +71,18 @@ func TestSmokeTests(t *testing.T) {
 					Query:    "SELECT NULL = NULL",
 					Expected: []sql.Row{{nil}},
 				},
+				{
+					Query:    ";",
+					Expected: []sql.Row{},
+				},
+				{
+					Query:    " ; ",
+					Expected: []sql.Row{},
+				},
+				{
+					Query:    "-- this is only a comment",
+					Expected: []sql.Row{},
+				},
 			},
 		},
 		{