fix(api): 修复商品保存事务重试冲突并兼容kind缺省

src/Api/TakeoutSaaS.TenantApi/Contracts/Product/ProductContracts.cs

@@ -80,7 +80,7 @@ public sealed class SaveProductRequest
     /// <summary>
     /// 商品类型（single/combo）。
     /// </summary>
-    public string Kind { get; set; } = "single";
+    public string? Kind { get; set; }
 
     /// <summary>
     /// 商品名称。

src/Api/TakeoutSaaS.TenantApi/Controllers/ProductController.cs

@@ -126,12 +126,10 @@ public sealed class ProductController(
         await EnsureStoreAccessibleAsync(storeId, cancellationToken);
 
         var categoryId = StoreApiHelpers.ParseRequiredSnowflake(request.CategoryId, nameof(request.CategoryId));
-        var kind = ParseKind(request.Kind);
         var productId = StoreApiHelpers.ParseSnowflakeOrNull(request.Id);
         var timedOnShelfAt = ParseTimedOnShelfAt(request.ShelfMode, request.TimedOnShelfAt);
         var normalizedStatus = ResolveStatusByShelfMode(request.ShelfMode, request.Status);
         var imageUrls = NormalizeImageUrls(request.ImageUrls);
-        var comboGroups = NormalizeComboGroups(request.ComboGroups, kind);
 
         ProductDto? existing = null;
         if (productId.HasValue)
@@ -147,6 +145,9 @@ public sealed class ProductController(
             }
         }
 
+        var kind = ResolveKindForSave(request.Kind, existing);
+        var comboGroups = NormalizeComboGroups(request.ComboGroups, kind);
+
         var shouldReplaceSpecAddon = existing is null || request.SpecTemplateIds is not null || request.AddonGroupIds is not null;
         var shouldReplaceLabels = existing is null || request.LabelIds is not null;
         var shouldReplaceSkus = existing is null || request.Skus is not null;
@@ -187,9 +188,16 @@ public sealed class ProductController(
         int? remainStock = soldoutMode.HasValue ? Math.Max(0, existing?.RemainStock ?? request.Stock) : null;
         var soldoutReason = soldoutMode.HasValue ? existing?.SoldoutReason : null;
 
-        ProductDto? saved;
-        await using (var transaction = await dbContext.Database.BeginTransactionAsync(cancellationToken))
+        ProductDto? saved = null;
+        var notFoundInTransaction = false;
+        var executionStrategy = dbContext.Database.CreateExecutionStrategy();
+        await executionStrategy.ExecuteAsync(async () =>
         {
+            saved = null;
+            notFoundInTransaction = false;
+            dbContext.ChangeTracker.Clear();
+
+            await using var transaction = await dbContext.Database.BeginTransactionAsync(cancellationToken);
             if (existing is null)
             {
                 saved = await mediator.Send(new CreateProductCommand
@@ -261,7 +269,8 @@ public sealed class ProductController(
 
             if (saved is null)
             {
-                return ApiResponse<ProductDetailResponse>.Error(ErrorCodes.NotFound, "商品不存在");
+                notFoundInTransaction = true;
+                return;
             }
 
             if (shouldReplaceSpecAddon)
@@ -281,9 +290,14 @@ public sealed class ProductController(
 
             await ReplaceComboGroupsAsync(saved.Id, storeId, kind, comboGroups, cancellationToken);
             await transaction.CommitAsync(cancellationToken);
+        });
+
+        if (notFoundInTransaction || saved is null)
+        {
+            return ApiResponse<ProductDetailResponse>.Error(ErrorCodes.NotFound, "商品不存在");
         }
 
-        var savedProduct = saved!;
+        var savedProduct = saved;
         var detailComboGroups = await BuildComboGroupResponsesAsync(savedProduct.Id, storeId, cancellationToken);
         var categoryNameLookup = await BuildCategoryNameLookupAsync(storeId, cancellationToken);
         var savedRelationState = await LoadProductRelationStateAsync(savedProduct.Id, storeId, cancellationToken);
@@ -727,6 +741,16 @@ public sealed class ProductController(
         };
     }
 
+    private static ProductKind ResolveKindForSave(string? kind, ProductDto? existing)
+    {
+        if (string.IsNullOrWhiteSpace(kind))
+        {
+            return existing?.Kind ?? ProductKind.Single;
+        }
+
+        return ParseKind(kind);
+    }
+
     private static ProductKind? ParseKindOrNull(string? kind)
     {
         if (string.IsNullOrWhiteSpace(kind))