SQL panic in statement summary when generating hints

[jackysp]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

[2023/08/21 16:00:06.472 +08:00] [Error] [conn.go:1072] ["connection running loop panic"] [conn=2319074532142588377] 
    [err="runtime error: invalid memory address or nil pointer dereference"] 
    [stack="github.com/pingcap/tidb/server.(*clientConn).Run.func1\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/server/conn.go:1075\n
    runtime.gopanic\n\t/usr/local/go/src/runtime/panic.go:884\n
    runtime.panicmem\n\t/usr/local/go/src/runtime/panic.go:260\n
    runtime.sigpanic\n\t/usr/local/go/src/runtime/signal_unix.go:841\n
    github.com/pingcap/tidb/planner/core.getJoinHints\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/planner/core/hints.go:111\n
    github.com/pingcap/tidb/planner/core.genHintsFromSingle\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/planner/core/hints.go:263\n
    github.com/pingcap/tidb/planner/core.GenHintsFromFlatPlan\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/planner/core/hints.go:44\n
    github.com/pingcap/tidb/executor.getEncodedPlan\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/executor/adapter.go:1753\n
    github.com/pingcap/tidb/executor.(*ExecStmt).SummaryStmt.func1\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/executor/adapter.go:1810\n
    github.com/pingcap/tidb/util/stmtsummary.newStmtSummaryByDigestElement\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/util/stmtsummary/statement_summary.go:635\n
    github.com/pingcap/tidb/util/stmtsummary.(*stmtSummaryByDigest).add.func1\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/util/stmtsummary/statement_summary.go:590\n
    github.com/pingcap/tidb/util/stmtsummary.(*stmtSummaryByDigest).add\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/util/stmtsummary/statement_summary.go:601\n
    github.com/pingcap/tidb/util/stmtsummary.(*stmtSummaryByDigestMap).AddStatement\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/util/stmtsummary/statement_summary.go:344\n
    github.com/pingcap/tidb/util/stmtsummary/v2.Add\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/util/stmtsummary/v2/stmtsummary.go:537\n
    github.com/pingcap/tidb/executor.(*ExecStmt).SummaryStmt\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/executor/adapter.go:1908\n
    github.com/pingcap/tidb/executor.(*ExecStmt).FinishExecuteStmt\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/executor/adapter.go:1354\n
    github.com/pingcap/tidb/executor.(*ExecStmt).CloseRecordSet\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/executor/adapter.go:1435\n
    github.com/pingcap/tidb/executor.(*recordSet).Close\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/executor/adapter.go:181\n
    github.com/pingcap/tidb/session.(*execStmtResult).Close\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/session/session.go:2449\n
    github.com/pingcap/tidb/server.(*tidbResultSet).Close\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/server/driver_tidb.go:476\n
    github.com/pingcap/tidb/parser/terror.Call\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/parser/terror/terror.go:315\n
    github.com/pingcap/tidb/server.(*clientConn).executePreparedStmtAndWriteResult\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/server/conn_stmt.go:429\n
    github.com/pingcap/tidb/server.(*clientConn).executePlanCacheStmt\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/server/conn_stmt.go:235\n
    github.com/pingcap/tidb/server.(*clientConn).handleStmtExecute\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/server/conn_stmt.go:227\n
    github.com/pingcap/tidb/server.(*clientConn).dispatch\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/server/conn.go:1399\n
    github.com/pingcap/tidb/server.(*clientConn).Run\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/server/conn.go:1153\n
    github.com/pingcap/tidb/server.(*Server).onConn\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb/server/server.go:677"]

2. What did you expect to see? (Required)

No panic

3. What did you see instead (Required)

Panic

4. What is your TiDB version? (Required)

v7.1.0 and v7.1.1

[seiya-annie]

/found gs