[BatchResolver] hangs when parent resolver returns Task<T> with multiple parent items #9892

Product

Hot Chocolate

Version

16.1.3

Link to minimal reproduction

https://github.com/ben-hamida/HotChocolateBatchResolverBug

Steps to reproduce

1. Clone https://github.com/ben-hamida/HotChocolateBatchResolverBug
2. Run dotnet run Program.cs

What is expected?

All three tests complete successfully.

What is actually happening?

Test 1 and 2 complete, Test 3 hangs indefinitely. The hang is uncancellable (CancellationToken is not respected).

Additional context

The bug requires:

• Parent resolver returning Task (async)
• Multiple parent items (2+)
• Nested [BatchResolver] on children

With a single parent item, the async resolver works correctly.