fix: initialize transactionMu correctly and ensure the transitivity o…

…f transactionMu.

adapter.go

@@ -202,6 +202,7 @@ func NewAdapterByDBUseTableName(db *gorm.DB, prefix string, tableName string) (*
 	a := &Adapter{
 		tablePrefix: prefix,
 		tableName:   tableName,
+		transactionMu : &sync.Mutex{},
 	}
 
 	a.db = db.Scopes(a.casbinRuleTable()).Session(&gorm.Session{Context: db.Statement.Context})
@@ -262,6 +263,7 @@ func NewFilteredAdapterByDB(db *gorm.DB, prefix string, tableName string) (*Adap
 		tablePrefix: prefix,
 		tableName:   tableName,
 		isFiltered:  true,
+		transactionMu : &sync.Mutex{},
 	}
 	adapter.db = db.Scopes(adapter.casbinRuleTable()).Session(&gorm.Session{Context: db.Statement.Context})
 
@@ -690,31 +692,22 @@ func (a *Adapter) AddPolicies(sec string, ptype string, rules [][]string) error
 
 // Transaction perform a set of operations within a transaction
 func (a *Adapter) Transaction(e casbin.IEnforcer, fc func(casbin.IEnforcer) error, opts ...*sql.TxOptions) error {
-	// ensure the transactionMu is initialized
-	if a.transactionMu == nil {
-		for a.muInitialize.CompareAndSwap(false, true) {
-			if a.transactionMu == nil {
-				a.transactionMu = &sync.Mutex{}
-			}
-			a.muInitialize.Store(false)
-		}
-	}
 	// lock the transactionMu to ensure the transaction is thread-safe
 	a.transactionMu.Lock()
 	defer a.transactionMu.Unlock()
 	var err error
 	oriAdapter := a.db
 	// reload policy from database to sync with the transaction
 	defer func() {
-		e.SetAdapter(&Adapter{db: oriAdapter})
+		e.SetAdapter(&Adapter{db: oriAdapter, transactionMu: a.transactionMu})
 		err = e.LoadPolicy()
 		if err != nil {
 			panic(err)
 		}
 	}()
 	copyDB := *a.db
 	tx := copyDB.Begin(opts...)
-	b := &Adapter{db: tx}
+	b := &Adapter{db: tx, transactionMu: a.transactionMu}
 	// copy enforcer to set the new adapter with transaction tx
 	copyEnforcer := e
 	copyEnforcer.SetAdapter(b)