executor: fix pipelined window invalid memory address (#30418) (#30460)

close #30326

executor/pipelined_window.go

@@ -179,7 +179,7 @@ func (e *PipelinedWindowExec) getRowsInPartition(ctx context.Context) (err error
 		var drained, samePartition bool
 		drained, err = e.fetchChild(ctx)
 		if err != nil {
-			err = errors.Trace(err)
+			return errors.Trace(err)
 		}
 		// we return immediately to use a combination of true newPartition but 0 in e.rowToConsume to indicate the data source is drained,
 		if drained {

expression/integration_test.go

@@ -10548,3 +10548,15 @@ func (s *testIntegrationSuite) TestIssue29513(c *C) {
 	tk.MustQuery("select '123' union select cast(a as char) from t;").Sort().Check(testkit.Rows("123", "45678"))
 	tk.MustQuery("select '123' union select cast(a as char(2)) from t;").Sort().Check(testkit.Rows("123", "45"))
 }
+
+func (s *testIntegrationSuite) TestIssue30326(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists t;")
+	tk.MustExec("create table t(a int);")
+	tk.MustExec("insert into t values(1),(1),(2),(2);")
+	tk.MustExec("set tidb_window_concurrency = 1;")
+	err := tk.QueryToErr("select (FIRST_VALUE(1) over (partition by v.a)) as c3 from (select a from t where t.a = (select a from t t2 where t.a = t2.a)) as v;")
+	c.Assert(err, NotNil)
+	c.Assert(err.Error(), Equals, "[executor:1242]Subquery returns more than 1 row")
+}