From 8d1e3d153c3be6a213043403022a69e4d36519be Mon Sep 17 00:00:00 2001
From: SysAdmin <sysadmin@silverlabs.uk>
Date: Sun, 5 Oct 2025 16:33:33 +0100
Subject: [PATCH] Fix: Manually load ProductVariants with separate query
 instead of Include
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**Root Cause**: EF Core Include() was not properly materializing the Variants navigation
property despite correct SQL JOIN generation.

**Solution**: Load variants separately and manually group by ProductId for DTO mapping.
This bypasses EF Core's navigation property fixup issues.

🤖 Generated with Claude Code
Co-Authored-By: Claude <noreply@anthropic.com>
---
 LittleShop/Services/ProductService.cs | 80 +++++++++++++++++----------
 1 file changed, 50 insertions(+), 30 deletions(-)

diff --git a/LittleShop/Services/ProductService.cs b/LittleShop/Services/ProductService.cs
index f03d515..9a09ca8 100644
--- a/LittleShop/Services/ProductService.cs
+++ b/LittleShop/Services/ProductService.cs
@@ -22,11 +22,19 @@ public class ProductService : IProductService
             .Include(p => p.Category)
             .Include(p => p.Photos)
             .Include(p => p.MultiBuys)
-            .Include(p => p.Variants)
             .Where(p => p.IsActive)
-            .AsSplitQuery()
             .ToListAsync();
 
+        // Manually load variants for all products
+        var productIds = products.Select(p => p.Id).ToList();
+        var allVariants = await _context.ProductVariants
+            .Where(v => productIds.Contains(v.ProductId))
+            .ToListAsync();
+
+        // Group variants by ProductId for quick lookup
+        var variantsByProduct = allVariants.GroupBy(v => v.ProductId)
+            .ToDictionary(g => g.Key, g => g.ToList());
+
         return products.Select(p => new ProductDto
             {
                 Id = p.Id,
@@ -63,19 +71,21 @@ public class ProductService : IProductService
                     CreatedAt = mb.CreatedAt,
                     UpdatedAt = mb.UpdatedAt
                 }).ToList(),
-                Variants = p.Variants.Select(v => new ProductVariantDto
-                {
-                    Id = v.Id,
-                    ProductId = v.ProductId,
-                    VariantType = v.VariantType,
-                    Name = v.Name,
-                    Price = v.Price,
-                    StockLevel = v.StockLevel,
-                    SortOrder = v.SortOrder,
-                    IsActive = v.IsActive,
-                    CreatedAt = v.CreatedAt,
-                    UpdatedAt = v.UpdatedAt
-                }).ToList()
+                Variants = variantsByProduct.ContainsKey(p.Id)
+                    ? variantsByProduct[p.Id].Select(v => new ProductVariantDto
+                    {
+                        Id = v.Id,
+                        ProductId = v.ProductId,
+                        VariantType = v.VariantType,
+                        Name = v.Name,
+                        Price = v.Price,
+                        StockLevel = v.StockLevel,
+                        SortOrder = v.SortOrder,
+                        IsActive = v.IsActive,
+                        CreatedAt = v.CreatedAt,
+                        UpdatedAt = v.UpdatedAt
+                    }).ToList()
+                    : new List<ProductVariantDto>()
             }).ToList();
     }
 
@@ -85,11 +95,19 @@ public class ProductService : IProductService
             .Include(p => p.Category)
             .Include(p => p.Photos)
             .Include(p => p.MultiBuys)
-            .Include(p => p.Variants)
             .Where(p => p.IsActive && p.CategoryId == categoryId)
-            .AsSplitQuery()
             .ToListAsync();
 
+        // Manually load variants for all products
+        var productIds = products.Select(p => p.Id).ToList();
+        var allVariants = await _context.ProductVariants
+            .Where(v => productIds.Contains(v.ProductId))
+            .ToListAsync();
+
+        // Group variants by ProductId for quick lookup
+        var variantsByProduct = allVariants.GroupBy(v => v.ProductId)
+            .ToDictionary(g => g.Key, g => g.ToList());
+
         return products.Select(p => new ProductDto
             {
                 Id = p.Id,
@@ -126,19 +144,21 @@ public class ProductService : IProductService
                     CreatedAt = mb.CreatedAt,
                     UpdatedAt = mb.UpdatedAt
                 }).ToList(),
-                Variants = p.Variants.Select(v => new ProductVariantDto
-                {
-                    Id = v.Id,
-                    ProductId = v.ProductId,
-                    VariantType = v.VariantType,
-                    Name = v.Name,
-                    Price = v.Price,
-                    StockLevel = v.StockLevel,
-                    SortOrder = v.SortOrder,
-                    IsActive = v.IsActive,
-                    CreatedAt = v.CreatedAt,
-                    UpdatedAt = v.UpdatedAt
-                }).ToList()
+                Variants = variantsByProduct.ContainsKey(p.Id)
+                    ? variantsByProduct[p.Id].Select(v => new ProductVariantDto
+                    {
+                        Id = v.Id,
+                        ProductId = v.ProductId,
+                        VariantType = v.VariantType,
+                        Name = v.Name,
+                        Price = v.Price,
+                        StockLevel = v.StockLevel,
+                        SortOrder = v.SortOrder,
+                        IsActive = v.IsActive,
+                        CreatedAt = v.CreatedAt,
+                        UpdatedAt = v.UpdatedAt
+                    }).ToList()
+                    : new List<ProductVariantDto>()
             }).ToList();
     }