From d046310cc96d2f58e7ef8c0ecdbb400875a62cdc Mon Sep 17 00:00:00 2001
From: Marc Pichler <marc.pichler@dynatrace.com>
Date: Thu, 1 Feb 2024 16:07:05 +0100
Subject: [PATCH] fix(sdk-metrics): ignore in accumulation instead

---
 packages/sdk-metrics/src/Instruments.ts                     | 6 ------
 packages/sdk-metrics/src/aggregator/ExponentialHistogram.ts | 6 ++++++
 packages/sdk-metrics/src/aggregator/Histogram.ts            | 6 ++++++
 packages/sdk-metrics/test/Instruments.test.ts               | 2 --
 4 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/packages/sdk-metrics/src/Instruments.ts b/packages/sdk-metrics/src/Instruments.ts
index 78ccd75171f..f665952f059 100644
--- a/packages/sdk-metrics/src/Instruments.ts
+++ b/packages/sdk-metrics/src/Instruments.ts
@@ -54,12 +54,6 @@ export class SyncInstrument {
       );
       return;
     }
-    if (Number.isNaN(value)) {
-      diag.warn(
-        `NaN provided to metric ${this._descriptor.name}, ignoring to preserve the integrity of the metrics stream`
-      );
-      return;
-    }
     if (
       this._descriptor.valueType === ValueType.INT &&
       !Number.isInteger(value)
diff --git a/packages/sdk-metrics/src/aggregator/ExponentialHistogram.ts b/packages/sdk-metrics/src/aggregator/ExponentialHistogram.ts
index 93565802059..4f71549535d 100644
--- a/packages/sdk-metrics/src/aggregator/ExponentialHistogram.ts
+++ b/packages/sdk-metrics/src/aggregator/ExponentialHistogram.ts
@@ -193,6 +193,12 @@ export class ExponentialHistogramAccumulation implements Accumulation {
    * @param increment
    */
   updateByIncrement(value: number, increment: number) {
+    // NaN does not fall into any bucket, is not zero and should not be counted,
+    // NaN is never greater than max nor less than min, therefore return as there's nothing for us to do.
+    if (Number.isNaN(value)) {
+      return;
+    }
+
     if (value > this._max) {
       this._max = value;
     }
diff --git a/packages/sdk-metrics/src/aggregator/Histogram.ts b/packages/sdk-metrics/src/aggregator/Histogram.ts
index 60e5e8df05d..94cf9060393 100644
--- a/packages/sdk-metrics/src/aggregator/Histogram.ts
+++ b/packages/sdk-metrics/src/aggregator/Histogram.ts
@@ -72,6 +72,12 @@ export class HistogramAccumulation implements Accumulation {
   ) {}
 
   record(value: number): void {
+    // NaN does not fall into any bucket, is not zero and should not be counted,
+    // NaN is never greater than max nor less than min, therefore return as there's nothing for us to do.
+    if (Number.isNaN(value)) {
+      return;
+    }
+
     this._current.count += 1;
     this._current.sum += value;
 
diff --git a/packages/sdk-metrics/test/Instruments.test.ts b/packages/sdk-metrics/test/Instruments.test.ts
index 16b4fe2ad9f..4b354518310 100644
--- a/packages/sdk-metrics/test/Instruments.test.ts
+++ b/packages/sdk-metrics/test/Instruments.test.ts
@@ -135,7 +135,6 @@ describe('Instruments', () => {
       counter.add(1.2, { foo: 'bar' });
       // non-number values should be ignored.
       counter.add('1' as any);
-      counter.add(NaN);
 
       await validateExport(cumulativeReader, {
         dataPointType: DataPointType.SUM,
@@ -248,7 +247,6 @@ describe('Instruments', () => {
       upDownCounter.add(1.1, { foo: 'bar' });
       // non-number values should be ignored.
       upDownCounter.add('1' as any);
-      upDownCounter.add(NaN);
 
       await validateExport(deltaReader, {
         dataPointType: DataPointType.SUM,