runtime error: index out of range [1] with length 1

[yibin87]

Located that the issue is introduced by: #58500

stack="github.com/pingcap/tidb/pkg/executor/sortexec.processPanicAndLog\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/pkg/executor/sortexec/sort_util.go:52\ngithub.com/pingcap/tidb/pkg/executor/sortexec.(*TopNExec).executeTopN.func1\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/pkg/executor/sortexec/topn.go:458\nruntime.gopanic\n\t/go/pkg/mod/golang.org/[email protected]/src/runtime/panic.go:785\nruntime.goPanicIndex\n\t/go/pkg/mod/golang.org/[email protected]/src/runtime/panic.go:115\ngithub.com/pingcap/tidb/pkg/util/chunk.Row.IsNull\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/pkg/util/chunk/row.go:231\ngithub.com/pingcap/tidb/pkg/util/chunk.cmpFloat64\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/pkg/util/chunk/compare.go:113\ngithub.com/pingcap/tidb/pkg/executor/sortexec.(*SortExec).lessRow\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/pkg/executor/sortexec/sort.go:809\ngithub.com/pingcap/tidb/pkg/executor/sortexec.(*multiWayMergeImpl).Less\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/pkg/executor/sortexec/multi_way_merge.go:140\ncontainer/heap.down\n\t/go/pkg/mod/golang.org/[email protected]/src/container/heap/heap.go:108\ncontainer/heap.Init\n\t/go/pkg/mod/golang.org/[email protected]/src/container/heap/heap.go:45\ngithub.com/pingcap/tidb/pkg/executor/sortexec.(*diskSource).init\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/pkg/executor/sortexec/multi_way_merge.go:76\ngithub.com/pingcap/tidb/pkg/executor/sortexec.(*multiWayMerger).init\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/pkg/executor/sortexec/multi_way_merge.go:180\ngithub.com/pingcap/tidb/pkg/executor/sortexec.(*TopNExec).generateResultWithMultiWayMerge\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/pkg/executor/sortexec/topn.go:500\ngithub.com/pingcap/tidb/pkg/executor/sortexec.(*TopNExec).generateTopNResultsWhenSpillTriggered\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/pkg/executor/sortexec/topn.go:585\ngithub.com/pingcap/tidb/pkg/executor/sortexec.(*TopNExec).generateTopNResults\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/pkg/executor/sortexec/topn.go:602\ngithub.com/pingcap/tidb/pkg/executor/sortexec.(*TopNExec).executeTopN\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/pkg/executor/sortexec/topn.go:482

[EricZequan]

Can try again after #58771 merged.