Fixes

src/Polly.Core.Tests/Utils/CancellationTokenSourcePoolTests.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Threading;
 using Moq;
 using Polly.Core.Tests.Helpers;
@@ -14,6 +15,17 @@ public static IEnumerable<object[]> TimeProviders()
         yield return new object[] { new FakeTimeProvider() };
     }
 
+    [Fact]
+    public void ArgValidation_Ok()
+    {
+        var pool = CancellationTokenSourcePool.Create(TimeProvider.System);
+
+        Assert.Throws<ArgumentOutOfRangeException>(() => pool.Get(TimeSpan.Zero));
+        Assert.Throws<ArgumentOutOfRangeException>(() => pool.Get(TimeSpan.FromMilliseconds(-2)));
+
+        pool.Get(System.Threading.Timeout.InfiniteTimeSpan).Should().NotBeNull();
+    }
+
     [MemberData(nameof(TimeProviders))]
     [Theory]
     public void RentReturn_Reusable_EnsureProperBehavior(object timeProvider)

src/Polly.Core/Utils/CancellationTokenSourcePool.Disposable.cs

@@ -8,7 +8,7 @@ private sealed class DisposableCancellationTokenSourcePool : CancellationTokenSo
 
         public DisposableCancellationTokenSourcePool(TimeProvider timeProvider) => _timeProvider = timeProvider;
 
-        public override CancellationTokenSource Get(TimeSpan delay)
+        protected override CancellationTokenSource GetCore(TimeSpan delay)
         {
             var source = new CancellationTokenSource();
 

src/Polly.Core/Utils/CancellationTokenSourcePool.Pooled.cs

@@ -14,7 +14,7 @@ private sealed class PooledCancellationTokenSourcePool : CancellationTokenSource
             static cts => true);
         private readonly TimeProvider _timeProvider;
 
-        public override CancellationTokenSource Get(TimeSpan delay)
+        protected override CancellationTokenSource GetCore(TimeSpan delay)
         {
             var source = _pool.Get();
 

src/Polly.Core/Utils/CancellationTokenSourcePool.cs

@@ -15,9 +15,19 @@ public static CancellationTokenSourcePool Create(TimeProvider timeProvider)
         return new DisposableCancellationTokenSourcePool(timeProvider);
     }
 
-    public abstract CancellationTokenSource Get(TimeSpan delay);
+    public CancellationTokenSource Get(TimeSpan delay)
+    {
+        if (delay <= TimeSpan.Zero && delay != System.Threading.Timeout.InfiniteTimeSpan)
+        {
+            throw new ArgumentOutOfRangeException(nameof(delay), "Invalid delay specified.");
+        }
+
+        return GetCore(delay);
+    }
+
+    protected abstract CancellationTokenSource GetCore(TimeSpan delay);
 
     public abstract void Return(CancellationTokenSource source);
 
-    protected static bool IsCancellable(TimeSpan delay) => delay > TimeSpan.Zero;
+    protected static bool IsCancellable(TimeSpan delay) => delay != System.Threading.Timeout.InfiniteTimeSpan;
 }