Introduce Activity.IsStopped Property

src/libraries/System.Diagnostics.DiagnosticSource/ref/System.Diagnostics.DiagnosticSourceActivity.cs

@@ -25,6 +25,7 @@ public string? Id
         }
 
         public bool IsAllDataRequested { get { throw null; } set { throw null; } }
+        public bool IsStopped { get { throw null; } }
         public System.Diagnostics.ActivityIdFormat IdFormat { get { throw null; } }
         public System.Diagnostics.ActivityKind Kind  { get { throw null; } }
         public string OperationName { get { throw null; } }

src/libraries/System.Diagnostics.DiagnosticSource/src/System/Diagnostics/Activity.cs

@@ -684,9 +684,9 @@ public void Stop()
                 return;
             }
 
-            if (!IsFinished)
+            if (!IsStopped)
             {
-                IsFinished = true;
+                IsStopped = true;
 
                 if (Duration == TimeSpan.Zero)
                 {
@@ -951,7 +951,7 @@ internal static bool TryConvertIdToContext(string traceParent, string? traceStat
         /// </summary>
         public void Dispose()
         {
-            if (!IsFinished)
+            if (!IsStopped)
             {
                 Stop();
             }
@@ -1232,7 +1232,7 @@ private static unsafe long GetRandomNumber()
 
         private static bool ValidateSetCurrent(Activity? activity)
         {
-            bool canSet = activity == null || (activity.Id != null && !activity.IsFinished);
+            bool canSet = activity == null || (activity.Id != null && !activity.IsStopped);
             if (!canSet)
             {
                 NotifyError(new InvalidOperationException(SR.ActivityNotRunning));
@@ -1298,18 +1298,24 @@ private bool W3CIdFlagsSet
             get => (_w3CIdFlags & ActivityTraceFlagsIsSet) != 0;
         }
 
-        private bool IsFinished
+        /// <summary>
+        /// Indicates whether this <see cref="Activity"/> object is stopped
+        /// </summary>
+        /// <remarks>
+        /// When subscribing to <see cref="Activity"/> stop event using <see cref="ActivityListener.ActivityStopped"/>, the received <see cref="Activity"/> object in the event callback will have <see cref="IsStopped"/> as true.
+        /// </remarks>
+        public bool IsStopped
         {
-            get => (_state & State.IsFinished) != 0;
-            set
+            get => (_state & State.IsStopped) != 0;
+            private set
             {
                 if (value)
                 {
-                    _state |= State.IsFinished;
+                    _state |= State.IsStopped;
                 }
                 else
                 {
-                    _state &= ~State.IsFinished;
+                    _state &= ~State.IsStopped;
                 }
             }
         }
@@ -1623,7 +1629,7 @@ private enum State : byte
             FormatW3C = 0b_0_00000_10,
             FormatFlags = 0b_0_00000_11,
 
-            IsFinished = 0b_1_00000_00,
+            IsStopped = 0b_1_00000_00,
         }
     }
 

src/libraries/System.Diagnostics.DiagnosticSource/tests/ActivityTests.cs

@@ -299,7 +299,6 @@ public void ActivityIdOverflow()
             Assert.Equal('#', activity.Id[activity.Id.Length - 1]);
         }
 
-
         /// <summary>
         /// Tests activity start and stop
         /// Checks Activity.Current correctness, Id generation
@@ -320,6 +319,51 @@ public void StartStop()
             Assert.Null(Activity.Current);
         }
 
+        /// <summary>
+        /// Tests Activity.IsStopped
+        /// </summary>
+        [Fact]
+        public void IsStoppedTest()
+        {
+            using var activity = new Activity("activity");
+            Assert.False(activity.IsStopped);
+            activity.Start();
+            Assert.False(activity.IsStopped);
+            Assert.Equal(TimeSpan.Zero, activity.Duration);
+            activity.Stop();
+            Assert.NotEqual(TimeSpan.Zero, activity.Duration);
+            Assert.True(activity.IsStopped);
+
+            using var activity1 = new Activity("activity");
+            Assert.False(activity1.IsStopped);
+            activity1.Start();
+            Assert.False(activity1.IsStopped);
+            activity1.SetEndTime(DateTime.UtcNow.AddMinutes(1)); // Setting end time shouldn't mark the activity as stopped
+            Assert.False(activity1.IsStopped);
+            activity1.Stop();
+            Assert.True(activity1.IsStopped);
+
+            //
+            // Validate when receiving Start/Stop Activity events
+            //
+
+            using ActivitySource aSource = new ActivitySource("TestActivityIsStopped");
+            using ActivityListener listener = new ActivityListener();
+
+            listener.ShouldListenTo = (activitySource) => activitySource.Name == "TestActivityIsStopped";
+            listener.Sample = (ref ActivityCreationOptions<ActivityContext> activityOptions) => ActivitySamplingResult.AllData;
+            listener.ActivityStarted = a => Assert.False(a.IsStopped);
+            listener.ActivityStopped = a => Assert.True(a.IsStopped);
+            ActivitySource.AddActivityListener(listener);
+            Activity sourceActivity;
+            using (sourceActivity = aSource.StartActivity("a1"))
+            {
+                Assert.NotNull(sourceActivity);
+                Assert.False(sourceActivity.IsStopped);
+            }
+            Assert.True(sourceActivity.IsStopped);
+        }
+
         /// <summary>
         /// Tests Id generation
         /// </summary>