runtime error: index out of range [2] with length 1

[Thearas]

Bug Report

1. Minimal reproduce step (Required)

drop table if exists t1;
CREATE TABLE t1 (a int(11));
SELECT @v:=(SELECT 1 FROM t1 t2 LEFT JOIN t1 ON t1.a GROUP BY t1.a) FROM t1;

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

No panic.

3. What did you see instead (Required)

Panic:

[2021/02/20 18:31:16.184 +08:00] [ERROR] [conn.go:734] ["connection running loop panic"] [conn=5] [lastSQL="SELECT IF( @v:=LEAST((SELECT 1 FROM t1  t2 LEFT JOIN t1 ON (@v) GROUP BY t1.a), a), count(*), 1) FROM t1  GROUP BY a LIMIT 1"] [err="runtime error: index out of range [2] with length 1"] [stack="goroutine 982 [running]:\ngithub.com/pingcap/tidb/server.(*clientConn).Run.func1(0x3f8a0a0, 0xc001187950, 0xc000a2af00)\n\t/home/jenkins/agent/workspace/tidb_master/go/src/github.com/pingcap/tidb/server/conn.go:732 +0xee\npanic(0x3730fe0, 0xc00146e000)\n\t/usr/local/go/src/runtime/panic.go:679 +0x1b2\ngithub.com/pingcap/tidb/planner/core.(*expressionRewriter).toColumn(0xc0013c5380, 0xc0013af000)\n\t/home/jenkins/agent/workspace/tidb_master/go/src/github.com/pingcap/tidb/planner/core/expression_rewriter.go:1725 +0xfba\ngithub.com/pingcap/tidb/planner/core.(*expressionRewriter).Leave(0xc0013c5380, 0x3fa6ac0, 0xc0013af000, 0x3fa6ac0, 0xc0013af000, 0x203000)\n\t/home/jenkins/agent/workspace/tidb_master/go/src/github.com/pingcap/tidb/planner/core/expression_rewriter.go:1043 +0x1b42\ngithub.com/pingcap/parser/ast.(*ColumnName).Accept(0xc0013af000, 0x3f52260, 0xc0013c5380, 0x3fa6b20, 0xc0013c74d0, 0xc0009f4800)\n\t/home/jenkins/agent/workspace/tidb_master/go/pkg/mod/github.com/pingcap/parser@v0.0.0-20210203141130-32ef3e0e2e13/ast/expressions.go:527 +0x8a\ngithub.com/pingcap/parser/ast.(*ColumnNameExpr).Accept(0xc0013c74d0, 0x3f52260, 0xc0013c5380, 0xc0009f48c0, 0xc001452f50, 0x0)\n\t/home/jenkins/agent/workspace/tidb_master/go/pkg/mod/github.com/pingcap/parser@v0.0.0-20210203141130-32ef3e0e2e13/ast/expressions.go:589 +0x96\ngithub.com/pingcap/tidb/planner/core.(*PlanBuilder).rewriteExprNode(0xc001356a80, 0xc0013c5380, 0x3fc1e80, 0xc0013c74d0, 0xc0009f4801, 0x0, 0x0, 0x0, 0x0, 0x0, ...)\n\t/home/jenkins/agent/workspace/tidb_master/go/src/github.com/pingcap/tidb/planner/core/expression_rewriter.go:195 +0x8e\ngithub.com/pingcap/tidb/planner/core.(*PlanBuilder).rewriteWithPreprocess(0xc001356a80, 0x3f8a0a0, 0xc001400840, 0x3fc1e80, 0xc0013c74d0, 0x3fdd980, 0xc0009f48c0, 0x0, 0x0, 0x1b2f601, ...)\n\t/home/jenkins/agent/workspace/tidb_master/go/src/github.com/pingcap/tidb/planner/core/expression_rewriter.go:142 +0x163\ngithub.com/pingcap/tidb/planner/core.(*PlanBuilder).rewrite(0xc001356a80, 0x3f8a0a0, 0xc001400840, 0x3fc1e80, 0xc0013c74d0, 0x3fdd980, 0xc0009f48c0, 0x0, 0x1, 0x0, ...)\n\t/home/jenkins/agent/workspace/tidb_master/go/src/github.com/pingcap/tidb/planner/core/expression_rewriter.go:110 +0xb9\ngithub.com/pingcap/tidb/planner/core.(*PlanBuilder).resolveGbyExprs(0xc001356a80, 0x3f8a0a0, 0xc001400840, 0x3fdd980, 0xc0009f48c0, 0xc0014005d0, 0xc00145c068, 0x1, 0x1, 0x0, ...)\n\t/home/jenkins/agent/workspace/tidb_master/go/src/github.com/pingcap/tidb/planner/core/logical_plan_builder.go:3012 +0x347\ngithub.com/pingcap/tidb/planner/core.(*PlanBuilder).buildSelect(0xc001356a80, 0x3f8a0a0, 0xc001400840, 0xc001309900, 0x3fdd980, 0xc0009f48c0, 0x0, 0x0)\n\t/home/jenkins/agent/workspace/tidb_master/go/src/github.com/pingcap/tidb/planner/core/logical_plan_builder.go:3325 +0x1cce\ngithub.com/pingcap/tidb/planner/core.(*PlanBuilder).buildResultSetNode(0xc001356a80, 0x3f8a0a0, 0xc001400840, 0x3fa8ce0, 0xc001309900, 0x0, 0x0, 0xc001303750, 0x134eb1e)\n\t/home/jenkins/agent/workspace/tidb_master/go/src/github.com/pingcap/tidb/planner/core/logical_plan_builder.go:376 +0x974\ngithub.com/pingcap/tidb/planner/core.(*expressionRewriter).buildSubquery(0xc0013c52b0, 0x3f8a0a0, 0xc001400840, 0xc0013c7560, 0x0, 0x0, 0x0, 0x0)\n\t/home/jenkins/agent/workspace/tidb_master/go/src/github.com/pingcap/tidb/planner/core/expression_rewriter.go:325 +0x9e\ngithub.com/pingcap/tidb/planner/core.(*expressionRewriter).handleScalarSubquery(0xc0013c52b0, 0x3f8a0a0, 0xc001400840, 0xc0013c7560, 0x38, 0xc0002b1dd0, 0x203000)\n\t/home/jenkins/agent/workspace/tidb_master/go/src/github.com/pingcap/tidb/planner/core/expression_rewriter.go:947 +0x6a\ngithub.com/pingcap/tidb/planner/core.(*expressionRewriter).Enter(0xc0013c52b0, 0x3fa9280, 0xc0013c7560, 0xc000316d20, 0xc0013211e8, 0x2)\n\t/home/jenkins/agent/workspace/tidb_master/go/src/github.com/pingcap/tidb/planner/core/expression_rewriter.go:392 +0x91a\ngithub.com/pingcap/parser/ast.(*SubqueryExpr).Accept(0xc0013c7560, 0x3f52260, 0xc0013c52b0, 0x3fa79c0, 0xc0009b4fc0, 0xc0009b5000)\n\t/home/jenkins/agent/workspace/tidb_master/go/pkg/mod/github.com/pingcap/parser@v0."]

4. What is your TiDB version? (Required)

Release Version: v4.0.0-beta.2-2148-g381ac81f2-dirty
Edition: Community
Git Commit Hash: 381ac81f2df09093096c0bda4ba2c9118b759488
Git Branch: master
UTC Build Time: 2021-02-19 14:00:26
GoVersion: go1.13
Race Enabled: false
TiKV Min Version: v3.0.0-60965b006877ca7234adaced7890d7b029ed1306
Check Table Before Drop: false

[qw4990]

Thanks for your feedback. I will fix it soon.

[ti-srebot]

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