fix(distribution): 人工批次窗口期防退款穿透与退款中途金额单调性加固

backend/internal/modules/payment/refund.go

@@ -415,6 +415,15 @@ func (r *Repository) markRefundFailedOrderStatus(ctx context.Context, orderID ui
 	return r.markOrderRefundFailed(ctx, orderID, refundAmountCent)
 }
 
+func refundedTotalTx(tx *gorm.DB, orderID uint64) (int64, error) {
+	var refundedTotal int64
+	err := tx.Model(&model.PaymentOrder{}).
+		Where("order_id = ? AND status = ?", orderID, "refunded").
+		Where("biz_type IN ?", refundBizTypes).
+		Select("COALESCE(SUM(amount_cent), 0)").Scan(&refundedTotal).Error
+	return refundedTotal, err
+}
+
 func (r *Repository) updateOrderRefundStatus(ctx context.Context, orderID uint64, refundAmountCent int64, bizType string) error {
 	return r.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
 		var order model.RentalOrder
@@ -424,11 +433,8 @@ func (r *Repository) updateOrderRefundStatus(ctx context.Context, orderID uint64
 		// 同一订单可能多笔退款，且退款结果查询会重复回调：
 		// 以已退款成功流水合计为口径，并取本次金额与累计额的较大值，
 		// 保证 order.RefundAmountCent 单调不回退、重复回调幂等。
-		var refundedTotal int64
-		if err := tx.Model(&model.PaymentOrder{}).
-			Where("order_id = ? AND status = ?", orderID, "refunded").
-			Where("biz_type IN ?", refundBizTypes).
-			Select("COALESCE(SUM(amount_cent), 0)").Scan(&refundedTotal).Error; err != nil {
+		refundedTotal, err := refundedTotalTx(tx, orderID)
+		if err != nil {
 			return err
 		}
 		cumulative := max(refundAmountCent, refundedTotal)
@@ -448,18 +454,31 @@ func (r *Repository) updateOrderRefundStatus(ctx context.Context, orderID uint64
 	})
 }
 func (r *Repository) markOrderRefunding(ctx context.Context, orderID uint64, refundAmountCent int64) error {
-	return r.db.WithContext(ctx).Model(&model.RentalOrder{}).Where("id = ?", orderID).Updates(map[string]any{
-		"refund_status":      "refunding",
-		"refund_amount_cent": refundAmountCent,
-		"refunded_at":        nil,
-	}).Error
+	return r.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
+		refundedTotal, err := refundedTotalTx(tx, orderID)
+		if err != nil {
+			return err
+		}
+		cumulative := max(refundAmountCent, refundedTotal)
+		return tx.Model(&model.RentalOrder{}).Where("id = ?", orderID).Updates(map[string]any{
+			"refund_status":      "refunding",
+			"refund_amount_cent": cumulative,
+			"refunded_at":        nil,
+		}).Error
+	})
 }
 func (r *Repository) markOrderRefundFailed(ctx context.Context, orderID uint64, refundAmountCent int64) error {
-	return r.db.WithContext(ctx).Model(&model.RentalOrder{}).Where("id = ?", orderID).Updates(map[string]any{
-		"refund_status":      "failed",
-		"refund_amount_cent": refundAmountCent,
-		"refunded_at":        nil,
-	}).Error
+	return r.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
+		refundedTotal, err := refundedTotalTx(tx, orderID)
+		if err != nil {
+			return err
+		}
+		return tx.Model(&model.RentalOrder{}).Where("id = ?", orderID).Updates(map[string]any{
+			"refund_status":      "failed",
+			"refund_amount_cent": refundedTotal,
+			"refunded_at":        nil,
+		}).Error
+	})
 }
 func (r *Repository) updateRefundRawRequest(ctx context.Context, paymentID uint64, rawRequest map[string]string) error {
 	if rawRequest == nil {

backend/internal/modules/payment/refund_cumulative_test.go

@@ -94,3 +94,50 @@ func TestUpdateOrderRefundStatusUsesCumulativeRefundedAmount(t *testing.T) {
 		t.Fatalf("重复回调后 order.RefundAmountCent = %d, want 1000（单调不回退）", saved.RefundAmountCent)
 	}
 }
+
+// TestMarkOrderRefundingAndFailedPreserveCumulativeRefund 断言已成功退款的订单
+// 发生后续退款中或退款失败时，累计退款额不会被单笔处理金额冲减缩小。
+func TestMarkOrderRefundingAndFailedPreserveCumulativeRefund(t *testing.T) {
+	db := setupPaymentTestDB(t)
+	repo := NewRepository(db, nil, nil)
+
+	order := model.RentalOrder{
+		OrderNo: "ORD-REF-PRESERVE", ListingID: 1, AccountID: 1, OwnerID: 1, RenterID: 2,
+		Status: "completed", RentAmountCent: 10000, OwnerRentAmountCent: 6000,
+	}
+	if err := db.Create(&order).Error; err != nil {
+		t.Fatal(err)
+	}
+
+	// 先前已成功退款 5000。
+	prevRefund := model.PaymentOrder{
+		PaymentNo: "REF-PREV-1", OrderID: order.ID, OrderNo: order.OrderNo, UserID: order.RenterID,
+		Provider: "mock", ThirdOrderID: "REF-PREV-1", AmountCent: 5000, BizType: "admin_refund", Status: "refunded",
+	}
+	if err := db.Create(&prevRefund).Error; err != nil {
+		t.Fatal(err)
+	}
+
+	// 此时发起了另一笔 2000 的退款中：累计额应为 max(2000, 5000) = 5000。
+	if err := repo.markOrderRefunding(t.Context(), order.ID, 2000); err != nil {
+		t.Fatal(err)
+	}
+	var saved model.RentalOrder
+	if err := db.First(&saved, order.ID).Error; err != nil {
+		t.Fatal(err)
+	}
+	if saved.RefundStatus != "refunding" || saved.RefundAmountCent != 5000 {
+		t.Fatalf("markOrderRefunding 后状态 = %s/%d, want refunding/5000", saved.RefundStatus, saved.RefundAmountCent)
+	}
+
+	// 该笔 2000 退款最终失败：累计退款额还原为已成功流水合计 5000，而不是单笔 2000。
+	if err := repo.markOrderRefundFailed(t.Context(), order.ID, 2000); err != nil {
+		t.Fatal(err)
+	}
+	if err := db.First(&saved, order.ID).Error; err != nil {
+		t.Fatal(err)
+	}
+	if saved.RefundStatus != "failed" || saved.RefundAmountCent != 5000 {
+		t.Fatalf("markOrderRefundFailed 后状态 = %s/%d, want failed/5000", saved.RefundStatus, saved.RefundAmountCent)
+	}
+}