Don't send filtered OTel spans to Sentry

src/Sentry.OpenTelemetry/SentrySpanProcessor.cs

@@ -181,6 +181,14 @@ public override void OnEnd(Activity data)
             return;
         }
 
+        // Skip any activities that are not recorded.
+        if (data is { Recorded: false, IsAllDataRequested: false })
+        {
+            _options?.DiagnosticLogger?.LogDebug($"Ignoring unrecorded Activity {data.SpanId}.");
+            _map.TryRemove(data.SpanId, out _);
+            return;
+        }
+
         // Make a dictionary of the attributes (aka "tags") for faster lookup when used throughout the processor.
         var attributes = data.TagObjects.ToDict();
 

test/Sentry.OpenTelemetry.Tests/SentrySpanProcessorTests.cs

@@ -459,6 +459,88 @@ public void OnEnd_FinishesTransaction()
         }
     }
 
+    [Fact]
+    public void OnEnd_FilteredTransaction_DoesNotFinishTransaction()
+    {
+        // Arrange
+        _fixture.Options.Instrumenter = Instrumenter.OpenTelemetry;
+        var sut = _fixture.GetSut();
+
+        var parent = Tracer.StartActivity("transaction")!;
+        sut.OnStart(parent);
+
+        var data = Tracer.StartActivity("test operation", kind: ActivityKind.Internal)!;
+        data.DisplayName = "test display name";
+        sut.OnStart(data);
+
+        FilterActivity(parent);
+
+        sut._map.TryGetValue(parent.SpanId, out var span);
+
+        // Act
+        sut.OnEnd(data);
+        sut.OnEnd(parent);
+
+        // Assert
+        if (span is not TransactionTracer transaction)
+        {
+            Assert.Fail("Span is not a transaction tracer");
+            return;
+        }
+
+        using (new AssertionScope())
+        {
+            transaction.EndTimestamp.Should().BeNull();
+            transaction.Status.Should().BeNull();
+        }
+    }
+
+    [Fact]
+    public void OnEnd_FilteredSpan_RemovesSpan()
+    {
+        // Arrange
+        _fixture.Options.Instrumenter = Instrumenter.OpenTelemetry;
+        var sut = _fixture.GetSut();
+
+        var parent = Tracer.StartActivity("transaction")!;
+        sut.OnStart(parent);
+
+        var data = Tracer.StartActivity("test operation", kind: ActivityKind.Internal)!;
+        data.DisplayName = "test display name";
+        sut.OnStart(data);
+
+        FilterActivity(data);
+
+        sut._map.TryGetValue(parent.SpanId, out var parentSpan);
+        sut._map.TryGetValue(data.SpanId, out var childSpan);
+
+        // Act
+        sut.OnEnd(data);
+        sut.OnEnd(parent);
+
+        // Assert
+        if (parentSpan is not TransactionTracer transaction)
+        {
+            Assert.Fail("parentSpan is not a transaction tracer");
+            return;
+        }
+        if (childSpan is not SpanTracer span)
+        {
+            Assert.Fail("span is not a span tracer");
+            return;
+        }
+
+        using (new AssertionScope())
+        {
+            span.EndTimestamp.Should().BeNull();
+            span.Status.Should().BeNull();
+
+            transaction.EndTimestamp.Should().NotBeNull();
+            transaction.Status.Should().Be(SpanStatus.Ok);
+            transaction.Spans.Should().BeEmpty();
+        }
+    }
+
     [Theory]
     [InlineData(OtelSemanticConventions.AttributeUrlFull)]
     [InlineData(OtelSemanticConventions.AttributeHttpUrl)]