From a7794ed8cff533b499905001f0bc2acf5315b3b5 Mon Sep 17 00:00:00 2001
From: Bogdan Drutu <bogdandrutu@gmail.com>
Date: Mon, 13 Apr 2020 10:10:24 -0700
Subject: [PATCH] Fix MetricAndDataPointCount to deal with nil (#825)

Signed-off-by: Bogdan Drutu <bogdandrutu@gmail.com>
---
 internal/data/metric.go      | 27 +++++++++++++------
 internal/data/metric_test.go | 52 ++++++++++++++++++++++++++++++++++++
 2 files changed, 71 insertions(+), 8 deletions(-)

diff --git a/internal/data/metric.go b/internal/data/metric.go
index 2cc6d79d834..d6f6e57cf3a 100644
--- a/internal/data/metric.go
+++ b/internal/data/metric.go
@@ -86,19 +86,30 @@ func (md MetricData) MetricCount() int {
 	return metricCount
 }
 
-// MetricAndDataPointCount calculates the total number of metrics and datapoints.
+// MetricAndDataPointCount calculates the total number of metrics and data points.
 func (md MetricData) MetricAndDataPointCount() (metricCount int, dataPointCount int) {
 	rms := md.ResourceMetrics()
 	for i := 0; i < rms.Len(); i++ {
-		ilms := rms.At(i).InstrumentationLibraryMetrics()
+		rm := rms.At(i)
+		if rm.IsNil() {
+			continue
+		}
+		ilms := rm.InstrumentationLibraryMetrics()
 		for j := 0; j < ilms.Len(); j++ {
-			metrics := ilms.At(j).Metrics()
+			ilm := ilms.At(j)
+			if ilm.IsNil() {
+				continue
+			}
+			metrics := ilm.Metrics()
 			metricCount += metrics.Len()
-			for k := 0; k < metrics.Len(); k++ {
-				dataPointCount += metrics.At(k).Int64DataPoints().Len()
-				dataPointCount += metrics.At(k).DoubleDataPoints().Len()
-				dataPointCount += metrics.At(k).HistogramDataPoints().Len()
-				dataPointCount += metrics.At(k).SummaryDataPoints().Len()
+			ms := ilm.Metrics()
+			for k := 0; k < ms.Len(); k++ {
+				m := ms.At(k)
+				if m.IsNil() {
+					continue
+				}
+				dataPointCount += m.Int64DataPoints().Len() + m.DoubleDataPoints().Len() +
+					m.HistogramDataPoints().Len() + m.SummaryDataPoints().Len()
 			}
 		}
 	}
diff --git a/internal/data/metric_test.go b/internal/data/metric_test.go
index 0f09cf7fd64..bb95652efa9 100644
--- a/internal/data/metric_test.go
+++ b/internal/data/metric_test.go
@@ -115,6 +115,58 @@ func TestMetricAndDataPointCount(t *testing.T) {
 	assert.EqualValues(t, 4, dps)
 }
 
+func TestMetricAndDataPointCountWithNil(t *testing.T) {
+	ms, dps := MetricDataFromOtlp([]*otlpmetrics.ResourceMetrics{nil, {}}).MetricAndDataPointCount()
+	assert.EqualValues(t, 0, ms)
+	assert.EqualValues(t, 0, dps)
+
+	ms, dps = MetricDataFromOtlp([]*otlpmetrics.ResourceMetrics{
+		{
+			InstrumentationLibraryMetrics: []*otlpmetrics.InstrumentationLibraryMetrics{nil, {}},
+		},
+	}).MetricAndDataPointCount()
+	assert.EqualValues(t, 0, ms)
+	assert.EqualValues(t, 0, dps)
+
+	ms, dps = MetricDataFromOtlp([]*otlpmetrics.ResourceMetrics{
+		{
+			InstrumentationLibraryMetrics: []*otlpmetrics.InstrumentationLibraryMetrics{
+				{
+					Metrics: []*otlpmetrics.Metric{nil, {}},
+				},
+			},
+		},
+	}).MetricAndDataPointCount()
+	assert.EqualValues(t, 2, ms)
+	assert.EqualValues(t, 0, dps)
+
+	ms, dps = MetricDataFromOtlp([]*otlpmetrics.ResourceMetrics{
+		{
+			InstrumentationLibraryMetrics: []*otlpmetrics.InstrumentationLibraryMetrics{
+				{
+					Metrics: []*otlpmetrics.Metric{{
+						Int64DataPoints: []*otlpmetrics.Int64DataPoint{
+							nil, {},
+						},
+						DoubleDataPoints: []*otlpmetrics.DoubleDataPoint{
+							nil, {},
+						},
+						HistogramDataPoints: []*otlpmetrics.HistogramDataPoint{
+							nil, {},
+						},
+						SummaryDataPoints: []*otlpmetrics.SummaryDataPoint{
+							nil, {},
+						},
+					}},
+				},
+			},
+		},
+	}).MetricAndDataPointCount()
+	assert.EqualValues(t, 1, ms)
+	assert.EqualValues(t, 8, dps)
+
+}
+
 func TestOtlpToInternalReadOnly(t *testing.T) {
 	metricData := MetricDataFromOtlp([]*otlpmetrics.ResourceMetrics{
 		{