runtime error: invalid memory address or nil pointer dereference by merge unconsumedCopStats

[jiyfhust]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

    analyze_test.go:1874: 

        	Error Trace:	pkg/executor/test/analyzetest/analyze_test.go:1874

        	            				pkg/executor/test/analyzetest/analyze_test.go:2027

        	            				pkg/executor/test/analyzetest/analyze_test.go:2030

        	Error:      	Not equal: 

        	            	expected: "[executor:1317]Query execution was interrupted"

        	            	actual  : "runtime error: invalid memory address or nil pointer dereference"

        	            	

        	            	Diff:

        	            	--- Expected

        	            	+++ Actual

        	            	@@ -1 +1 @@

        	            	-[executor:1317]Query execution was interrupted

        	            	+runtime error: invalid memory address or nil pointer dereference

        	Test:       	TestKillAutoAnalyzeIndex

        	Messages:   	kill running analyze job

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

3. What did you see instead (Required)

4. What is your TiDB version? (Required)

[jiyfhust]

/component test

[jiyfhust]

https://do.pingcap.net/jenkins/blue/organizations/jenkins/pingcap%2Ftidb%2Fghpr_unit_test/detail/ghpr_unit_test/6266/pipeline

[jiyfhust]

Introduced by #51787.

diff --git a/pkg/distsql/select_result.go b/pkg/distsql/select_result.go
@@ -607,6 +613,15 @@ func (r *selectResult) Close() error {
                unconsumedCopStats := unconsumed.CollectUnconsumedCopRuntimeStats()
                for _, copStats := range unconsumedCopStats {
                        _ = r.updateCopRuntimeStats(context.Background(), copStats, time.Duration(0))
+                       if (r.ctx == nil) {
+                               logutil.BgLogger().Error("iiiiiiiiiiiiii")
+                       }

then go test --tags=intest --run="TestKillAutoAnalyzeIndex"

when test fails, where will be a log:

[2024/03/20 16:23:33.236 +08:00] [ERROR] [select_result.go:611] [iiiiiiiiiiiiii] [stack="github.com/pingcap/tidb/pkg/distsql............

[jiyfhust]

/severity moderate