Merge pull request #12778 from turbolay/fixTryShouldNotThrow

`TryRemoveLastFilterIfNewerThanAsync` should not throw

WalletWasabi.Tests/UnitTests/Stores/IndexStoreTests.cs

@@ -3,6 +3,7 @@
 using System.Runtime.CompilerServices;
 using System.Threading;
 using System.Threading.Tasks;
+using WalletWasabi.Backend.Models;
 using WalletWasabi.Blockchain.Blocks;
 using WalletWasabi.Helpers;
 using WalletWasabi.Stores;
@@ -19,14 +20,22 @@ public class IndexStoreTests
 	[Fact]
 	public async Task IndexStoreTestsAsync()
 	{
-		using CancellationTokenSource testDeadlineCts = new(TimeSpan.FromMinutes(1));
+		using CancellationTokenSource testCts = new(TimeSpan.FromMinutes(1));
 
 		string directory = GetWorkDirectory();
 		await IoHelpers.TryDeleteDirectoryAsync(directory);
 		IoHelpers.EnsureContainingDirectoryExists(directory);
 
 		await using var indexStore = new IndexStore(directory, Network.Main, new SmartHeaderChain());
-		await indexStore.InitializeAsync(testDeadlineCts.Token);
+		await indexStore.InitializeAsync(testCts.Token);
+
+		// Remove starting filter.
+		FilterModel? filterModel = await indexStore.TryRemoveLastFilterAsync();
+		Assert.NotNull(filterModel);
+
+		// No filter to remove.
+		filterModel = await indexStore.TryRemoveLastFilterAsync();
+		Assert.Null(filterModel);
 	}
 
 	private string GetWorkDirectory([CallerFilePath] string callerFilePath = "", [CallerMemberName] string callerMemberName = "")

WalletWasabi/Stores/IndexStore.cs

@@ -317,14 +317,14 @@ public async Task<FilterModel[]> FetchBatchAsync(uint fromHeight, int batchSize,
 			{
 				if (!IndexStorage.TryRemoveLast(out filter))
 				{
-					throw new InvalidOperationException("No last filter.");
+					return null;
 				}
 			}
 			else
 			{
 				if (!IndexStorage.TryRemoveLastIfNewerThan(height.Value, out filter))
 				{
-					throw new InvalidOperationException("No last filter.");
+					return null;
 				}
 			}