fix: use preparestmt in trasaction will use new conn, close #5508

gorm.go

@@ -248,11 +248,19 @@ func (db *DB) Session(config *Session) *DB {
 	if config.PrepareStmt {
 		if v, ok := db.cacheStore.Load(preparedStmtDBKey); ok {
 			preparedStmt := v.(*PreparedStmtDB)
+			switch t := tx.Statement.ConnPool.(type) {
+			case Tx:
+				tx.Statement.ConnPool = &PreparedStmtTX{
+					Tx:             t,
+					PreparedStmtDB: preparedStmt,
+				}
+			default:
 				tx.Statement.ConnPool = &PreparedStmtDB{
 					ConnPool: db.Config.ConnPool,
 					Mux:      preparedStmt.Mux,
 					Stmts:    preparedStmt.Stmts,
 				}
+			}
 			txConfig.ConnPool = tx.Statement.ConnPool
 			txConfig.PrepareStmt = true
 		}

tests/prepared_stmt_test.go

@@ -2,6 +2,7 @@ package tests_test
 
 import (
 	"context"
+	"errors"
 	"testing"
 	"time"
 
@@ -88,3 +89,19 @@ func TestPreparedStmtFromTransaction(t *testing.T) {
 	}
 	tx2.Commit()
 }
+
+func TestPreparedStmtInTransaction(t *testing.T) {
+	user := User{Name: "jinzhu"}
+
+	if err := DB.Transaction(func(tx *gorm.DB) error {
+		tx.Session(&gorm.Session{PrepareStmt: true}).Create(&user)
+		return errors.New("test")
+	}); err == nil {
+		t.Error(err)
+	}
+
+	var result User
+	if err := DB.First(&result, user.ID).Error; err == nil {
+		t.Errorf("Failed, got error: %v", err)
+	}
+}