Fix transaction leak when using Session in Scopes

callbacks/transaction.go

@@ -8,7 +8,7 @@ func BeginTransaction(db *gorm.DB) {
 	if !db.Config.SkipDefaultTransaction && db.Error == nil {
 		if tx := db.Begin(); tx.Error == nil {
 			db.Statement.ConnPool = tx.Statement.ConnPool
-			db.InstanceSet("gorm:started_transaction", true)
+			db.Statement.Settings.Store("gorm:started_transaction", true)
 		} else if tx.Error == gorm.ErrInvalidTransaction {
 			tx.Error = nil
 		} else {
@@ -19,7 +19,7 @@ func BeginTransaction(db *gorm.DB) {
 
 func CommitOrRollbackTransaction(db *gorm.DB) {
 	if !db.Config.SkipDefaultTransaction {
-		if _, ok := db.InstanceGet("gorm:started_transaction"); ok {
+		if _, ok := db.Statement.Settings.Load("gorm:started_transaction"); ok {
 			if db.Error != nil {
 				db.Rollback()
 			} else {

tests/transaction_leak_test.go

@@ -0,0 +1,64 @@
+package tests_test
+
+import (
+	"testing"
+
+	"gorm.io/gorm"
+	. "gorm.io/gorm/utils/tests"
+)
+
+func TestTransactionLeakWithScopesSession(t *testing.T) {
+	var users []User
+
+	// Get the underlying sql.DB to check connection stats
+	sqldb, err := DB.DB()
+	if err != nil {
+		t.Error(err)
+	}
+
+	before := sqldb.Stats().InUse
+
+	// This should not leak transactions - the issue case
+	result := DB.Scopes(func(s *gorm.DB) *gorm.DB {
+		return s.Session(&gorm.Session{
+			DryRun: true,
+		})
+	}).Where("name = ?", "transaction-leak-test").Find(&users)
+
+	if result.Error != nil {
+		t.Errorf("Query failed: %v", result.Error)
+	}
+
+	after := sqldb.Stats().InUse
+
+	if before != after {
+		t.Errorf("Transaction leak detected: InUse connections before=%d, after=%d", before, after)
+	}
+}
+
+func TestTransactionLeakWithScopesSessionDelete(t *testing.T) {
+	// Get the underlying sql.DB to check connection stats
+	sqldb, err := DB.DB()
+	if err != nil {
+		t.Error(err)
+	}
+
+	before := sqldb.Stats().InUse
+
+	// This should not leak transactions - the more specific case from the playground
+	result := DB.Scopes(func(s *gorm.DB) *gorm.DB {
+		return s.Session(&gorm.Session{
+			DryRun: true,
+		})
+	}).Where("name = ?", "transaction-leak-test").Delete(&User{})
+
+	if result.Error != nil {
+		t.Errorf("Delete failed: %v", result.Error)
+	}
+
+	after := sqldb.Stats().InUse
+
+	if before != after {
+		t.Errorf("Transaction leak detected: InUse connections before=%d, after=%d", before, after)
+	}
+}