Update method throws an exception, because the entity is already tracked - entity-framework

Question

I have a problem with EF Core 5 that is really getting me down.
FYI, LazyLoadingProxies are used (something else that just gives me a headache, but well, different topic).
Information for the code below:
Service: A service per entity, contains all CRUD operations into the database and other methods if needed.
Workflow: Uses multiple services at once to perform certain operations (e.g. create product -> create product folder -> save product).
Problem:
I have an entity "Product" which contains the following update method which is used to update the properties of the entity with those of another object:
public override void Update(Product source)
{
// Properties
AnnualPrice = source.AnnualPrice;
...
// Relations
var sourceRelatedProductIds = source.RelatedWithProductIds.Where(x => x != Id);
if (sourceRelatedProductIds.Count() != 0)
{
RelatedWithProducts.Clear();
foreach (var relatedWithProduct in ctx.Set<Product>().Where(x => source.RelatedWithProductIds.Contains(x.Id)).AsNoTracking())
{
RelatedWithProducts.Add(relatedWithProduct);
}
}
var oldShortDescriptions = ShortDescriptions.ToList(); <--- EXCEPTION
ShortDescriptions.Clear();
foreach (var shortDescription in source.ShortDescriptions)
{
shortDescription.Id = oldShortDescriptions.FirstOrDefault(x => x.Culture == shortDescription.Culture)?.Id ?? 0;
ShortDescriptions.Add(shortDescription);
}
...
}
In the line with the arrow and "Exception", I get the following exception:
System.InvalidOperationException: 'The instance of entity type 'Product' cannot be tracked because another instance with the key value '{Id: 1}' is already being tracked. When attaching existing entities, ensure that only one entity instance with a given key value is attached.'
In itself, I understand what the exception is trying to tell me. My problem is that I can't find the reason for it anywhere. Because as far as I can tell, the product with ID 1 can't be tracked yet.
Of course, the problem is not in the update method, but before it, so here is the rest of the code.
ProductController.Update:
[HttpPut("update")]
public IActionResult Update(C.Product[] products)
{
if (!ModelState.IsValid)
{
return UnprocessableEntity(ModelState.Values.SelectMany(x => x.Errors));
}
var dbProducts = products.Select(ToDatabase).ToArray(); <--- Just converts the given client model into a Database model
var result = productWorkflow.Update(dbProducts); <--- Calls a workflow class, NOT the update method of the entity
return CoreToActionResultConverter.ToActionResult<Db.Product>(result);
}
ProductWorkflow.Update:
public ResultBase Update(params Product[] products)
{
var result = productService.AddOrUpdate(products); <--- This calls the Service CRUD AddOrUpdate method
if (result is not ServiceResult<Product>)
{
return result;
}
return new ServiceResult<Product>(ResultType.AddedOrUpdated);
}
ProductService.AddOrUpdate:
public virtual ResultBase AddOrUpdate(IEnumerable<TEntity> entities)
{
var currentEntities = new List<TEntity>();
foreach (var entity in entities)
{
var currentEntity = Get(entity.Id); <--- This line is the only one where I could imagine that it is already tracked here. The problem is only that it does not work ONLY with the workflow. If I call my AddOrUpdate method from the controller, which directly calls THIS method, it works (although this line is just executed the same way).
if (currentEntity == null)
{
currentEntity = Ctx.CreateProxy<TEntity>();
Ctx.Attach(currentEntity);
}
if (currentEntity != entity)
{
currentEntity.Update(entity);
}
currentEntities.Add(currentEntity);
}
Ctx.AddRange(currentEntities.Where(x => x.Id == 0));
Ctx.UpdateRange(currentEntities.Where(x => x.Id != 0));
try
{
Ctx.SaveChanges();
}
catch (DbUpdateException ex)
{
// Commented out the error handling to remove unnecessary things for the post
}
return new ServiceResult<TEntity>(ServiceResult.ResultType.AddedOrUpdated, currentEntities);
}

Answer 1

I found the problem and it was not on the line where the exception was thrown, but before.
In my Product.Update() method (the first code snippet), I get the Related Products by ID and add them to the list (Simply a Many to Many relationship, from Product <--> Product). When calling Update, I specified ID 1 in the RelatedProductIds, however the entity itself also has ID 1, so it references itself. I have now just fixed that by omitting the ID, if the same as the object itself.
This still doesn't explain why it works with a breakpoint, because it's still tracked in that case (or not tracked, since I'm using AsNoTracking(), but good).