address PR feedback

sessionctx/variable/sysvar.go

@@ -492,29 +492,10 @@ func UnregisterSysVar(name string) {
  sysVarsLock.Unlock()
 }
 
-// copySv deep copies the sysvar struct to avoid a race
-func copySv(src *SysVar) (dest *SysVar) {
- return &SysVar{
- Scope: src.Scope,
- Name: src.Name,
- Value: src.Value,
- Type: src.Type,
- MinValue: src.MinValue,
- MaxValue: src.MaxValue,
- AutoConvertNegativeBool: src.AutoConvertNegativeBool,
- AutoConvertOutOfRange: src.AutoConvertOutOfRange,
- ReadOnly: src.ReadOnly,
- PossibleValues: src.PossibleValues,
- AllowEmpty: src.AllowEmpty,
- AllowEmptyAll: src.AllowEmptyAll,
- AllowAutoValue: src.AllowAutoValue,
- Validation: src.Validation,
- SetSession: src.SetSession,
- SetGlobal: src.SetGlobal,
- IsHintUpdatable: src.IsHintUpdatable,
- Hidden: src.Hidden,
- Aliases: src.Aliases,
- }
+// Clone deep copies the sysvar struct to avoid a race
+func (sv *SysVar) Clone() *SysVar {
+ dst := *sv
+ return &dst
 }
 
 // GetSysVar returns sys var info for name as key.
@@ -525,7 +506,7 @@ func GetSysVar(name string) *SysVar {
  if sysVars[name] == nil {
  return nil
  }
- return copySv(sysVars[name])
+ return sysVars[name].Clone()
 }
 
 // SetSysVar sets a sysvar. This will not propagate to the cluster, so it should only be
@@ -543,7 +524,7 @@ func GetSysVars() map[string]*SysVar {
  defer sysVarsLock.RUnlock()
  copy := make(map[string]*SysVar, len(sysVars))
  for name, sv := range sysVars {
- copy[name] = copySv(sv)
+ copy[name] = sv.Clone()
  }
  return copy
 }