Merge branch '1.15.x'

Author: shakuzen

build.gradle

@@ -94,7 +94,9 @@ subprojects {
                     "CollectionUndefinedEquality",
                     "DefaultCharset",
                     "DoNotCallSuggester",
+                    "EnumOrdinal",
                     "EqualsGetClass",
+                    "FallThrough",
                     "InlineFormatString",
                     "LongDoubleConversion",
                     "MissingOverride",

implementations/micrometer-registry-prometheus/src/test/java/io/micrometer/prometheusmetrics/PrometheusMeterRegistryIntegrationTest.java

@@ -151,9 +151,10 @@ private void recordMetrics() {
         TimeGauge.builder("test.tg", () -> 42, MILLISECONDS).register(registry);
 
         List<Measurement> measurements = new ArrayList<>();
-        for (int i = 0; i < Statistic.values().length; i++) {
-            final int value = i;
-            measurements.add(new Measurement(() -> value + 10, Statistic.values()[i]));
+        int i = 0;
+        for (Statistic statistic : Statistic.values()) {
+            int value = i++;
+            measurements.add(new Measurement(() -> value + 10, statistic));
         }
         Meter.builder("test.custom", Meter.Type.OTHER, measurements).register(registry);
     }

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

@@ -31,7 +31,7 @@ static Histogram stackdriverHistogram(Clock clock, DistributionStatisticConfig d
         if (distributionStatisticConfig.isPublishingHistogram()) {
             return new StackdriverFixedBoundaryHistogram(clock, distributionStatisticConfig);
         }
-        return NoopHistogram.INSTANCE;
+        return new StackdriverInfinityBucketHistogram(clock, distributionStatisticConfig);
     }
 
     static class StackdriverClientSidePercentilesHistogram extends TimeWindowPercentileHistogram {
@@ -51,4 +51,12 @@ static class StackdriverFixedBoundaryHistogram extends TimeWindowFixedBoundaryHi
 
     }
 
+    static class StackdriverInfinityBucketHistogram extends TimeWindowFixedBoundaryHistogram {
+
+        StackdriverInfinityBucketHistogram(Clock clock, DistributionStatisticConfig config) {
+            super(clock, config, false, false, true);
+        }
+
+    }
+
 }

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

@@ -20,6 +20,7 @@
 import io.micrometer.core.instrument.DistributionSummary;
 import io.micrometer.core.instrument.MockClock;
 import io.micrometer.core.instrument.Timer;
+import io.micrometer.core.instrument.distribution.CountAtBucket;
 import io.micrometer.core.instrument.distribution.HistogramSnapshot;
 import org.jspecify.annotations.Nullable;
 import org.junit.jupiter.api.Test;
@@ -76,11 +77,12 @@ void distributionCountBucketsInfinityBucketIsNotNegative() {
     @Test
     @Issue("#2045")
     void batchDistributionWhenHistogramSnapshotIsEmpty() {
-        // no SLOs, percentiles, or percentile histogram configured => no-op histogram
+        // no SLOs, percentiles, or percentile histogram configured
+        // => only infinity bucket histogram
         DistributionSummary ds = DistributionSummary.builder("ds").register(meterRegistry);
         StackdriverMeterRegistry.Batch batch = meterRegistry.new Batch();
         HistogramSnapshot histogramSnapshot = ds.takeSnapshot();
-        assertThat(histogramSnapshot.histogramCounts()).isEmpty();
+        assertThat(histogramSnapshot.histogramCounts()).containsExactly(new CountAtBucket(Double.POSITIVE_INFINITY, 0));
         assertThat(histogramSnapshot.percentileValues()).isEmpty();
         Distribution distribution = batch.distribution(histogramSnapshot, false);
         assertThat(distribution.getBucketOptions().getExplicitBuckets().getBoundsList()).containsExactly(0d);
@@ -196,4 +198,31 @@ void meanIsZeroWhenCountIsZero() {
         assertThat(distribution.getMean()).isZero();
     }
 
+    @Test
+    @Issue("#6401")
+    void distributionWithNoBucketsHasCountInHistogramTimeWindow() {
+        StackdriverMeterRegistry.Batch batch = meterRegistry.new Batch();
+
+        // half-way through the first step, example: 30s
+        clock.add(config.step().dividedBy(2));
+        DistributionSummary ds = DistributionSummary.builder("ds").register(meterRegistry);
+        ds.record(3);
+
+        // 1/4 through the second step, example: 1m15s
+        clock.add(config.step().dividedBy(4).multipliedBy(3));
+        // assert and make count rollover as would happen via scheduled rollover
+        assertThat(ds.count()).isOne();
+        ds.record(5);
+
+        // 3/4 through the second step, example: 1m45s
+        clock.add(config.step().dividedBy(2));
+        assertThat(ds.count()).isOne();
+        ds.record(7);
+
+        Distribution distribution = batch.distribution(ds.takeSnapshot(), false);
+        // still returns count for the previous step
+        assertThat(ds.count()).isOne();
+        assertThat(distribution.getCount()).isEqualTo(2);
+    }
+
 }

micrometer-core/src/main/java/io/micrometer/core/instrument/binder/jersey/server/MetricsRequestEventListener.java

@@ -78,6 +78,7 @@ public void onEvent(RequestEvent event) {
                 if (!isClientError(event)) {
                     break;
                 }
+                // fall through
             case REQUEST_MATCHED:
                 timedAnnotations = annotations(event);
 

micrometer-core/src/main/java/io/micrometer/core/instrument/binder/jersey/server/ObservationRequestEventListener.java

@@ -70,6 +70,7 @@ public void onEvent(RequestEvent event) {
                 if (!isNotFoundException(event)) {
                     break;
                 }
+                // fall through
             case REQUEST_MATCHED:
                 JerseyContext jerseyContext = new JerseyContext(event);
                 Observation observation = JerseyObservationDocumentation.DEFAULT.start(this.customConvention,

micrometer-core/src/test/java/io/micrometer/core/instrument/binder/jetty/JettyClientMetricsTest.java

@@ -61,6 +61,7 @@ public void handle(String target, org.eclipse.jetty.server.Request baseRequest,
                         throw new RuntimeException("big boom");
                     case "/error":
                         response.setStatus(500);
+                        // fall through
                     case "/ok":
                         baseRequest.setHandled(true);
                 }