Lazy loader throwing invalid operation exceptions

[MoazAlkharfan]

File a bug

Include your code

Assuming it's because of concurrent access to memory cached entities after they have been loaded and the DbContext has already been disposed.

Reproduction repository: https://github.com/MoazAlkharfan/efcore-issue-32390

Places to check:

• TagsCacheService fetch data from db
• Program mapped / endpoint
• ServerRequest do get requests on the / endpoint

Include stack traces

For the first:

efcore/src/EFCore/Infrastructure/Internal/LazyLoader.cs

Lines 181 to 183 in 141740f

	private bool IsLoading((object Entity, string NavigationName) navEntry)
	=> (_isLoading ??= new List<(object Entity, string NavigationName)>())
	.Contains(navEntry, EntityNavigationEqualityComparer.Instance);

System.InvalidOperationException: Collection was modified; enumeration operation may not execute.
   at System.Collections.Generic.List`1.Enumerator.MoveNext()
   at System.Linq.Enumerable.Contains[TSource](IEnumerable`1 source, TSource value, IEqualityComparer`1 comparer)
   at Microsoft.EntityFrameworkCore.Infrastructure.Internal.LazyLoader.Load(Object entity, String navigationName)
   at Castle.DynamicProxy.AbstractInvocation.Proceed()

efcore/src/EFCore/Infrastructure/Internal/LazyLoader.cs

Lines 185 to 195 in 141740f

	private void DoneLoading((object Entity, string NavigationName) navEntry)
	{
	for (var i = 0; i < _isLoading!.Count; i++)
	{
	if (EntityNavigationEqualityComparer.Instance.Equals(navEntry, _isLoading[i]))
	{
	_isLoading.RemoveAt(i);
	break;
	}
	}
	}

For the second:

System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection. (Parameter 'index')
   at Microsoft.EntityFrameworkCore.Infrastructure.Internal.LazyLoader.Load(Object entity, String navigationName)
   at Castle.DynamicProxy.AbstractInvocation.Proceed()

Include provider and version information

EF Core version: 8.0
Database provider: (Microsoft.EntityFrameworkCore.SqlServer)
Target framework: (.NET 8.0)
Operating system: Windows/Linux
IDE: (Visual Studio 2022 17.9)

[ajcvickers]

This issue is lacking enough information for us to be able to fully understand what is happening. Please attach a small, runnable project or post a small, runnable code listing that reproduces what you are seeing so that we can investigate.

[MoazAlkharfan]

@ajcvickers
Reproduction repository: https://github.com/MoazAlkharfan/efcore-issue-32390

Places to check:

• TagsCacheService fetch data from db
• Program mapped / endpoint
• ServerRequest do get requests on the / endpoint