From f6aa990842ec00d98273acacc816c3028bad3294 Mon Sep 17 00:00:00 2001
From: Weizhen Wang <wangweizhen@pingcap.com>
Date: Fri, 7 Nov 2025 14:03:25 +0800
Subject: [PATCH] expression: Clone scalar function when to check the
 equivalence of the expression (#64298)

close pingcap/tidb#64156
---
 pkg/expression/scalar_function.go | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/pkg/expression/scalar_function.go b/pkg/expression/scalar_function.go
index 1f80b3cae0..fb415064fa 100644
--- a/pkg/expression/scalar_function.go
+++ b/pkg/expression/scalar_function.go
@@ -404,8 +404,10 @@ func assertCheckHashCode(sf *ScalarFunction) {
 	intest.Assert(intest.InTest)
 	copyhashcode := make([]byte, len(sf.hashcode))
 	copy(copyhashcode, sf.hashcode)
-	ReHashCode(sf)
-	intest.Assert(bytes.Equal(sf.hashcode, copyhashcode), "HashCode should not change after ReHashCode is called")
+	// avoid data race in the plan cache
+	s := sf.Clone().(*ScalarFunction)
+	ReHashCode(s)
+	intest.Assert(bytes.Equal(s.hashcode, copyhashcode), "HashCode should not change after ReHashCode is called")
 }
 
 // IsCorrelated implements Expression interface.