Fix bug in async Batch operator (#652)

Author: viceroypenguin

Source/SuperLinq.Async/Batch.cs

@@ -1,4 +1,4 @@
-namespace SuperLinq.Async;
+namespace SuperLinq.Async;
 
 public static partial class AsyncSuperEnumerable
 {
@@ -42,6 +42,7 @@ static async IAsyncEnumerable<IList<TSource>> Core(
 				if (n == size)
 				{
 					yield return array;
+					array = null;
 					n = 0;
 				}
 			}

Tests/SuperLinq.Async.Test/BatchTest.cs

@@ -1,4 +1,4 @@
-namespace Test.Async;
+namespace Test.Async;
 
 public sealed class BatchTest
 {
@@ -17,6 +17,20 @@ public void BatchValidatesSize()
 				.Batch(0));
 	}
 
+	[Fact]
+	public async Task BatchDoesNotReturnSameArrayInstance()
+	{
+		await using var seq = Enumerable.Range(1, 4).AsTestingSequence();
+		await using var e = seq.Batch(2).GetAsyncEnumerator();
+
+		_ = await e.MoveNextAsync();
+		var batch1 = e.Current;
+		_ = await e.MoveNextAsync();
+		var batch2 = e.Current;
+
+		Assert.NotEqual(batch1, batch2);
+	}
+
 	[Fact]
 	public async Task BatchWithEmptySource()
 	{

Tests/SuperLinq.Test/BatchTest.cs

@@ -44,6 +44,23 @@ public static IEnumerable<object[]> GetFourElementSequences() =>
 			.GetListSequences()
 			.Select(x => new object[] { x });
 
+	[Theory]
+	[MemberData(nameof(GetFourElementSequences))]
+	public void BatchDoesNotReturnSameArrayInstance(IDisposableEnumerable<int> seq)
+	{
+		using (seq)
+		{
+			using var e = seq.Batch(2).GetEnumerator();
+
+			_ = e.MoveNext();
+			var batch1 = e.Current;
+			_ = e.MoveNext();
+			var batch2 = e.Current;
+
+			Assert.NotEqual(batch1, batch2);
+		}
+	}
+
 	[Theory]
 	[MemberData(nameof(GetFourElementSequences))]
 	public void BatchModifiedBeforeMoveNextDoesNotAffectNextBatch(IDisposableEnumerable<int> seq)