From ba57bf8b2f91332d7b0d57609979d3e5b1d54e83 Mon Sep 17 00:00:00 2001
From: unknown <3676547+alanwest@users.noreply.github.com>
Date: Wed, 15 Mar 2023 13:11:20 -0700
Subject: [PATCH 1/2] Fix min/max snapshot for explicit bounds histogram

---
 src/OpenTelemetry/Metrics/HistogramBuckets.cs  |  2 ++
 .../Metrics/MetricSnapshotTests.cs             | 18 ++++++++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/src/OpenTelemetry/Metrics/HistogramBuckets.cs b/src/OpenTelemetry/Metrics/HistogramBuckets.cs
index f0cf3938299..fbe17269950 100644
--- a/src/OpenTelemetry/Metrics/HistogramBuckets.cs
+++ b/src/OpenTelemetry/Metrics/HistogramBuckets.cs
@@ -87,6 +87,8 @@ internal HistogramBuckets Copy()
 
             Array.Copy(this.SnapshotBucketCounts, copy.SnapshotBucketCounts, this.SnapshotBucketCounts.Length);
             copy.SnapshotSum = this.SnapshotSum;
+            copy.SnapshotMin = this.SnapshotMin;
+            copy.SnapshotMax = this.SnapshotMax;
 
             return copy;
         }
diff --git a/test/OpenTelemetry.Tests/Metrics/MetricSnapshotTests.cs b/test/OpenTelemetry.Tests/Metrics/MetricSnapshotTests.cs
index 9ea34769685..81df155b901 100644
--- a/test/OpenTelemetry.Tests/Metrics/MetricSnapshotTests.cs
+++ b/test/OpenTelemetry.Tests/Metrics/MetricSnapshotTests.cs
@@ -117,6 +117,9 @@ public void VerifySnapshot_Histogram()
             ref readonly var metricPoint1 = ref metricPoints1Enumerator.Current;
             Assert.Equal(1, metricPoint1.GetHistogramCount());
             Assert.Equal(10, metricPoint1.GetHistogramSum());
+            metricPoint1.TryGetHistogramMinMaxValues(out var min, out var max);
+            Assert.Equal(10, min);
+            Assert.Equal(10, max);
 
             // Verify Snapshot 1
             Assert.Single(exportedSnapshots);
@@ -124,6 +127,9 @@ public void VerifySnapshot_Histogram()
             Assert.Single(snapshot1.MetricPoints);
             Assert.Equal(1, snapshot1.MetricPoints[0].GetHistogramCount());
             Assert.Equal(10, snapshot1.MetricPoints[0].GetHistogramSum());
+            snapshot1.MetricPoints[0].TryGetHistogramMinMaxValues(out min, out max);
+            Assert.Equal(10, min);
+            Assert.Equal(10, max);
 
             // Verify Metric == Snapshot
             Assert.Equal(metric1.Name, snapshot1.Name);
@@ -141,6 +147,9 @@ public void VerifySnapshot_Histogram()
             // This value is expected to be updated.
             Assert.Equal(2, metricPoint1.GetHistogramCount());
             Assert.Equal(15, metricPoint1.GetHistogramSum());
+            metricPoint1.TryGetHistogramMinMaxValues(out min, out max);
+            Assert.Equal(5, min);
+            Assert.Equal(10, max);
 
             // Verify Metric 2
             Assert.Equal(2, exportedMetrics.Count);
@@ -150,11 +159,17 @@ public void VerifySnapshot_Histogram()
             ref readonly var metricPoint2 = ref metricPoints2Enumerator.Current;
             Assert.Equal(2, metricPoint2.GetHistogramCount());
             Assert.Equal(15, metricPoint2.GetHistogramSum());
+            metricPoint2.TryGetHistogramMinMaxValues(out min, out max);
+            Assert.Equal(5, min);
+            Assert.Equal(10, max);
 
             // Verify Snapshot 1 after second export
             // This value is expected to be unchanged.
             Assert.Equal(1, snapshot1.MetricPoints[0].GetHistogramCount());
             Assert.Equal(10, snapshot1.MetricPoints[0].GetHistogramSum());
+            snapshot1.MetricPoints[0].TryGetHistogramMinMaxValues(out min, out max);
+            Assert.Equal(10, min);
+            Assert.Equal(10, max);
 
             // Verify Snapshot 2
             Assert.Equal(2, exportedSnapshots.Count);
@@ -162,6 +177,9 @@ public void VerifySnapshot_Histogram()
             Assert.Single(snapshot2.MetricPoints);
             Assert.Equal(2, snapshot2.MetricPoints[0].GetHistogramCount());
             Assert.Equal(15, snapshot2.MetricPoints[0].GetHistogramSum());
+            snapshot2.MetricPoints[0].TryGetHistogramMinMaxValues(out min, out max);
+            Assert.Equal(5, min);
+            Assert.Equal(10, max);
         }
     }
 }

From daa464346390a467b1ec4d896881371bfe8dec3a Mon Sep 17 00:00:00 2001
From: unknown <3676547+alanwest@users.noreply.github.com>
Date: Wed, 15 Mar 2023 13:19:21 -0700
Subject: [PATCH 2/2] Update changelog

---
 src/OpenTelemetry.Exporter.InMemory/CHANGELOG.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/OpenTelemetry.Exporter.InMemory/CHANGELOG.md b/src/OpenTelemetry.Exporter.InMemory/CHANGELOG.md
index d8101b31014..4d6a10e2ca4 100644
--- a/src/OpenTelemetry.Exporter.InMemory/CHANGELOG.md
+++ b/src/OpenTelemetry.Exporter.InMemory/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+* Fixed issue where the `MetricSnapshot` of a histogram did not capture the min
+  and max values.
+  ([#4306](https://github.com/open-telemetry/opentelemetry-dotnet/pull/4306))
+
 ## 1.5.0-alpha.1
 
 Released 2023-Mar-07