Merge branch '4.0.x'

Closes gh-48584

module/spring-boot-webmvc/src/main/java/org/springframework/boot/webmvc/autoconfigure/WebMvcObservationAutoConfiguration.java

@@ -58,9 +58,9 @@ import org.springframework.web.servlet.DispatcherServlet;
 		"org.springframework.boot.micrometer.metrics.autoconfigure.export.simple.SimpleMetricsExportAutoConfiguration",
 		"org.springframework.boot.micrometer.observation.autoconfigure.ObservationAutoConfiguration" })
 @ConditionalOnWebApplication(type = Type.SERVLET)
-@ConditionalOnClass({ DispatcherServlet.class, Observation.class })
+@ConditionalOnClass({ DispatcherServlet.class, Observation.class, ObservationProperties.class })
 @ConditionalOnBean(ObservationRegistry.class)
-@EnableConfigurationProperties({ MetricsProperties.class, ObservationProperties.class })
+@EnableConfigurationProperties(ObservationProperties.class)
 public final class WebMvcObservationAutoConfiguration {
 
 	@Bean
@@ -79,8 +79,9 @@ public final class WebMvcObservationAutoConfiguration {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	@ConditionalOnClass(MeterRegistry.class)
+	@ConditionalOnClass({ MeterRegistry.class, MetricsProperties.class })
 	@ConditionalOnBean(MeterRegistry.class)
+	@EnableConfigurationProperties(MetricsProperties.class)
 	static class MeterFilterConfiguration {
 
 		@Bean

module/spring-boot-webmvc/src/test/java/org/springframework/boot/webmvc/autoconfigure/WebMvcObservationAutoConfigurationTests.java

@@ -31,8 +31,12 @@ import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 
 import org.springframework.boot.autoconfigure.AutoConfigurations;
+import org.springframework.boot.micrometer.metrics.MaximumAllowableTagsMeterFilter;
 import org.springframework.boot.micrometer.metrics.autoconfigure.MetricsAutoConfiguration;
+import org.springframework.boot.micrometer.metrics.autoconfigure.MetricsProperties;
 import org.springframework.boot.micrometer.observation.autoconfigure.ObservationAutoConfiguration;
+import org.springframework.boot.micrometer.observation.autoconfigure.ObservationProperties;
+import org.springframework.boot.test.context.FilteredClassLoader;
 import org.springframework.boot.test.context.assertj.AssertableWebApplicationContext;
 import org.springframework.boot.test.context.runner.WebApplicationContextRunner;
 import org.springframework.boot.test.system.CapturedOutput;
@@ -74,6 +78,12 @@ class WebMvcObservationAutoConfigurationTests {
 			.run((context) -> assertThat(context).doesNotHaveBean(FilterRegistrationBean.class));
 	}
 
+	@Test
+	void backsOffWhenObservationPropertiesIsMissing() {
+		this.contextRunner.withClassLoader(new FilteredClassLoader(ObservationProperties.class))
+			.run((context) -> assertThat(context).doesNotHaveBean(FilterRegistrationBean.class));
+	}
+
 	@Test
 	void definesFilterWhenRegistryIsPresent() {
 		this.contextRunner.run((context) -> {
@@ -171,6 +181,12 @@ class WebMvcObservationAutoConfigurationTests {
 			});
 	}
 
+	@Test
+	void shouldBackOffIfMetricsPropertiesIsNotPresent() {
+		this.contextRunner.withClassLoader(new FilteredClassLoader(MetricsProperties.class))
+			.run((context) -> assertThat(context).doesNotHaveBean(MaximumAllowableTagsMeterFilter.class));
+	}
+
 	private MeterRegistry getInitializedMeterRegistry(AssertableWebApplicationContext context) {
 		return getInitializedMeterRegistry(context, "/test0", "/test1", "/test2");
 	}