Merge branch 'main' into micrometer-metricsgh-1149

docs/build.gradle

@@ -28,7 +28,7 @@ dependencies {
 
     testImplementation project(':micrometer-test')
     testImplementation project(':micrometer-observation-test')
-    testImplementation 'org.aspectj:aspectjweaver'
+    testImplementation libs.aspectjweaver
     testImplementation 'org.junit.jupiter:junit-jupiter'
     testImplementation 'org.assertj:assertj-core'
     testImplementation 'org.springframework:spring-context'

docs/modules/ROOT/pages/concepts/meters.adoc

@@ -6,6 +6,6 @@ A `Meter` is the interface for collecting a set of measurements (which we indivi
 Micrometer supports a set of `Meter` primitives, including `Timer`, `Counter`, `Gauge`, `DistributionSummary`, `LongTaskTimer`, `FunctionCounter`, `FunctionTimer`, and `TimeGauge`. Different meter types result in a different number of time series metrics. For example, while there is a single metric that represents a `Gauge`, a `Timer` measures both the count of timed events and the total time of all timed events.
 
 TIP: Recording a measurement for a `Meter` is expected to be a relatively cheap operation and should not throw any exception.
-If the xref:./registry.adoc[registry] supports publishing metrics to a monitoring system, this is done in a separate thread snd should not affect recording metrics.
+If the xref:./registry.adoc[registry] supports publishing metrics to a monitoring system, this is done in a separate thread and should not affect recording metrics.
 
 A meter is uniquely identified by its name and dimensions. We use the terms, "`dimensions`" and "`tags,`" interchangeably, and the Micrometer interface is `Tag` simply because it is shorter. As a general rule, it should be possible to use the name as a pivot. Dimensions let a particular named metric be sliced to drill down and reason about the data. This means that, if only the name is selected, you can drill down by using other dimensions and reason about the value being shown.

micrometer-bom/build.gradle

@@ -12,6 +12,7 @@ dependencies {
                     !it.name.contains('concurrency-tests') &&
                     !it.name.contains('micrometer-bom') &&
                     !it.name.contains('micrometer-osgi-test') &&
+                    !it.name.contains('-test-aspectj') &&
                     it.name != 'docs'
         }.each {
             api(group: it.group,

micrometer-core/build.gradle

@@ -212,7 +212,7 @@ dependencies {
     testImplementation 'io.grpc:grpc-testing-proto'
     testImplementation 'com.squareup.retrofit2:retrofit'
 
-    testImplementation 'org.aspectj:aspectjweaver'
+    testImplementation libs.aspectjweaver
 }
 
 task shenandoahTest(type: Test) {

micrometer-observation-test/src/main/java/io/micrometer/observation/tck/ObservationValidator.java

@@ -16,6 +16,7 @@
 package io.micrometer.observation.tck;
 
 import io.micrometer.common.lang.Nullable;
+import io.micrometer.observation.NullObservation.NullContext;
 import io.micrometer.observation.Observation.Context;
 import io.micrometer.observation.Observation.Event;
 import io.micrometer.observation.ObservationHandler;
@@ -47,7 +48,7 @@ class ObservationValidator implements ObservationHandler<Context> {
     }
 
     ObservationValidator(Consumer<ValidationResult> consumer) {
-        this(consumer, context -> true);
+        this(consumer, context -> !(context instanceof NullContext));
     }
 
     ObservationValidator(Consumer<ValidationResult> consumer, Predicate<Context> supportsContextPredicate) {

micrometer-observation-test/src/test/java/io/micrometer/observation/tck/ObservationValidatorTests.java

@@ -15,6 +15,7 @@
  */
 package io.micrometer.observation.tck;
 
+import io.micrometer.observation.NullObservation;
 import io.micrometer.observation.Observation;
 import io.micrometer.observation.Observation.Event;
 import io.micrometer.observation.Observation.Scope;
@@ -253,4 +254,9 @@ void startErrorErrorStopShouldBeValid() {
         Observation.start("test", registry).error(new RuntimeException()).error(new RuntimeException()).stop();
     }
 
+    @Test
+    void nullObservationShouldBeIgnored() {
+        new NullObservation(registry).openScope();
+    }
+
 }

micrometer-observation/build.gradle

@@ -46,5 +46,5 @@ dependencies {
 
     testImplementation 'org.assertj:assertj-core'
     testImplementation 'org.awaitility:awaitility'
-    testImplementation 'org.aspectj:aspectjweaver'
+    testImplementation libs.aspectjweaver
 }

micrometer-observation/src/main/java/io/micrometer/observation/NullObservation.java

@@ -28,7 +28,7 @@
 public class NullObservation extends SimpleObservation {
 
     public NullObservation(ObservationRegistry registry) {
-        super("null", registry, new Context());
+        super("null", registry, new NullContext());
     }
 
     @Override
@@ -66,4 +66,16 @@ public Observation start() {
         return this;
     }
 
+    /**
+     * A special {@link Observation.Context} that should be used only in
+     * {@link NullObservation} in special cases where clearing of scopes is important. Its
+     * only purpose is to make scenarios through {@link NullObservation} distinguishable
+     * from "normal" {@link Observation Observations}.
+     *
+     * @since 1.14.0
+     */
+    public static class NullContext extends Context {
+
+    }
+
 }

micrometer-observation/src/main/java/io/micrometer/observation/Observations.java

@@ -36,7 +36,6 @@ public final class Observations {
             initialRegistry);
 
     private Observations() {
-        throw new UnsupportedOperationException("You can't instantiate a utility class");
     }
 
     /**

micrometer-observation/src/main/java/io/micrometer/observation/aop/ObservedAspect.java

@@ -85,7 +85,13 @@ public class ObservedAspect {
 
     private final Predicate<ProceedingJoinPoint> shouldSkip;
 
-    // For Compile Time Weaving
+    /**
+     * Create an {@code ObservedAspect} with {@link Observations#getGlobalRegistry()}.
+     *
+     * This is for compile-time weaving.
+     *
+     * @since 1.14.0
+     */
     public ObservedAspect() {
         this(Observations.getGlobalRegistry(), null, DONT_SKIP_ANYTHING);
     }

tests/micrometer-test-aspectj-ctw/build.gradle → micrometer-test-aspectj-ctw/build.gradle

@@ -6,9 +6,9 @@ plugins {
 description 'AspectJ compile-time weaving test for Micrometer aspects'
 
 dependencies {
-    implementation project(':micrometer-core')
     aspect project(':micrometer-core')
     aspect project(':micrometer-observation')
+    implementation libs.aspectjrt
 
     testImplementation libs.junitJupiter
     testImplementation libs.assertj

tests/micrometer-test-aspectj-ltw/src/test/java/io/micrometer/test/ltw/MeasuredClassTest.java → micrometer-test-aspectj-ltw/src/test/java/io/micrometer/test/ltw/MeasuredClassTest.java

@@ -27,11 +27,15 @@
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.condition.DisabledForJreRange;
+import org.junit.jupiter.api.condition.JRE;
 
 import java.util.Collection;
 
 import static org.assertj.core.api.BDDAssertions.then;
 
+@DisabledForJreRange(min = JRE.JAVA_17,
+        disabledReason = "See https://github.com/micrometer-metrics/micrometer/pull/5401#issuecomment-2308440259")
 class MeasuredClassTest {
 
     MeterRegistry registry = new SimpleMeterRegistry();