[OpenTelemetry] Metrics - beter handling for double.NaN v2

Author: Kielek

src/OpenTelemetry/Metrics/MeterProviderSdk.cs

@@ -219,6 +219,12 @@ internal static void MeasurementRecordedDouble(Instrument instrument, double val
             return;
         }
 
+        if (!MathHelper.IsFinite(value))
+        {
+            OpenTelemetrySdkEventSource.Log.MeasurementDropped(instrument?.Name ?? "UnknownInstrument", "Measurement value was invalid.", "Use a finite value for measurements (not NaN or Infinity).");
+            return;
+        }
+
         metricState.RecordMeasurementDouble(value, tags);
     }
 

test/OpenTelemetry.Tests/Metrics/MeterProviderSdkTests.cs

@@ -104,4 +104,30 @@ void RunTest()
             }
         }
     }
+
+    [Fact]
+    public void NonFiniteDoubleMeasurementsAreDropped()
+    {
+        var meterName = Utils.GetCurrentMethodName();
+        var exportedItems = new List<Metric>();
+
+        using var meterProvider = Sdk.CreateMeterProviderBuilder()
+            .AddMeter(meterName)
+            .AddInMemoryExporter(exportedItems)
+            .Build();
+
+        using var meter = new Meter(meterName);
+        var counter = meter.CreateCounter<double>("counter");
+
+        counter.Add(double.NaN);
+        counter.Add(double.PositiveInfinity);
+        counter.Add(double.NegativeInfinity);
+        counter.Add(2.5);
+
+        Assert.True(meterProvider.ForceFlush());
+        var exportedMetric = Assert.Single(exportedItems);
+        var metric = new MetricSnapshot(exportedMetric);
+        var metricPoint = Assert.Single(metric.MetricPoints);
+        Assert.Equal(2.5, metricPoint.GetSumDouble());
+    }
 }