Merge branch '1.1.x' into 1.3.x

implementations/micrometer-registry-stackdriver/src/main/java/io/micrometer/stackdriver/StackdriverMeterRegistry.java

@@ -279,7 +279,8 @@ public StackdriverMeterRegistry build() {
         }
     }
 
-    private class Batch {
+    //VisibleForTesting
+    class Batch {
         private final TimeInterval interval = TimeInterval.newBuilder()
                 .setEndTime(Timestamp.newBuilder()
                         .setSeconds(clock.wallTime() / 1000)
@@ -385,7 +386,8 @@ private String metricType(Meter.Id id, @Nullable String statistic) {
             return metricType.toString();
         }
 
-        private Distribution distribution(HistogramSnapshot snapshot, boolean timeDomain) {
+        //VisibleForTesting
+        Distribution distribution(HistogramSnapshot snapshot, boolean timeDomain) {
             CountAtBucket[] histogram = snapshot.histogramCounts();
 
             // selected finite buckets (represented as a normal histogram)
@@ -416,7 +418,7 @@ private Distribution distribution(HistogramSnapshot snapshot, boolean timeDomain
             }
 
             // add the "+infinity" bucket, which does NOT have a corresponding bucket boundary
-            bucketCounts.add(snapshot.count() - truncatedSum.get());
+            bucketCounts.add(Math.max(0, snapshot.count() - truncatedSum.get()));
 
             List<Double> bucketBoundaries = Arrays.stream(histogram)
                     .map(countAtBucket -> timeDomain ? countAtBucket.bucket(getBaseTimeUnit()) : countAtBucket.bucket())

implementations/micrometer-registry-stackdriver/src/test/java/io/micrometer/stackdriver/StackdriverMeterRegistryTest.java

@@ -0,0 +1,63 @@
+/**
+ * Copyright 2020 Pivotal Software, Inc.
+ * <p>
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * https://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.micrometer.stackdriver;
+
+import com.google.api.Distribution;
+import io.micrometer.core.Issue;
+import io.micrometer.core.instrument.MockClock;
+import io.micrometer.core.instrument.distribution.CountAtBucket;
+import io.micrometer.core.instrument.distribution.HistogramSnapshot;
+import io.micrometer.core.lang.Nullable;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link StackdriverMeterRegistry}
+ */
+class StackdriverMeterRegistryTest {
+
+    StackdriverMeterRegistry meterRegistry = new StackdriverMeterRegistry(new StackdriverConfig() {
+        @Override
+        public boolean enabled() {
+            return false;
+        }
+
+        @Override
+        public String projectId() {
+            return "doesnotmatter";
+        }
+
+        @Override
+        @Nullable
+        public String get(String key) {
+            return null;
+        }
+    }, new MockClock());
+
+    @Test
+    @Issue("#1325")
+    void distributionCountBucketsInfinityBucketIsNotNegative() {
+        StackdriverMeterRegistry.Batch batch = meterRegistry.new Batch();
+        // count is 4, but sum of bucket counts is 5 due to inconsistent snapshotting
+        HistogramSnapshot histogramSnapshot = new HistogramSnapshot(4, 14.7, 5, null, new CountAtBucket[]{new CountAtBucket(1, 2), new CountAtBucket(2, 5)}, null);
+        Distribution distribution = batch.distribution(histogramSnapshot, false);
+        List<Long> bucketCountsList = distribution.getBucketCountsList();
+        assertThat(bucketCountsList.get(bucketCountsList.size() - 1)).isNotNegative();
+    }
+}