Add support for configuring publishMaxGaugeForHistograms

See https://github.com/micrometer-metrics/micrometer/pull/6159
See gh-49242

module/spring-boot-micrometer-metrics/src/main/java/org/springframework/boot/micrometer/metrics/autoconfigure/export/otlp/OtlpMetricsProperties.java

@@ -86,6 +86,12 @@ public class OtlpMetricsProperties extends StepRegistryProperties {
 	 */
 	private final Map<String, Meter> meter = new LinkedHashMap<>();
 
+	/**
+	 * Whether to publish a separate gauge for the max value of histogram-based meters. A
+	 * null value defers to Micrometer's default.
+	 */
+	private @Nullable Boolean publishMaxGaugeForHistograms;
+
 	public @Nullable String getUrl() {
 		return this.url;
 	}
@@ -154,6 +160,14 @@ public class OtlpMetricsProperties extends StepRegistryProperties {
 		return this.meter;
 	}
 
+	public @Nullable Boolean getPublishMaxGaugeForHistograms() {
+		return this.publishMaxGaugeForHistograms;
+	}
+
+	public void setPublishMaxGaugeForHistograms(@Nullable Boolean publishMaxGaugeForHistograms) {
+		this.publishMaxGaugeForHistograms = publishMaxGaugeForHistograms;
+	}
+
 	/**
 	 * Per-meter settings.
 	 */

module/spring-boot-micrometer-metrics/src/main/java/org/springframework/boot/micrometer/metrics/autoconfigure/export/otlp/OtlpMetricsPropertiesConfigAdapter.java

@@ -121,6 +121,12 @@ class OtlpMetricsPropertiesConfigAdapter extends StepRegistryPropertiesConfigAda
 		return obtain(OtlpMetricsProperties::getBaseTimeUnit, OtlpConfig.super::baseTimeUnit);
 	}
 
+	@Override
+	public boolean publishMaxGaugeForHistograms() {
+		return obtain(OtlpMetricsProperties::getPublishMaxGaugeForHistograms,
+				OtlpConfig.super::publishMaxGaugeForHistograms);
+	}
+
 	private <V> Getter<OtlpMetricsProperties, Map<String, V>> perMeter(Getter<Meter, V> getter) {
 		return (properties) -> {
 			if (CollectionUtils.isEmpty(properties.getMeter())) {

module/spring-boot-micrometer-metrics/src/test/java/org/springframework/boot/micrometer/metrics/autoconfigure/export/otlp/OtlpMetricsPropertiesConfigAdapterTests.java

@@ -219,6 +219,24 @@ class OtlpMetricsPropertiesConfigAdapterTests {
 		assertThat(createAdapter().resourceAttributes()).doesNotContainKey("service.namespace");
 	}
 
+	@Test
+	void useDefaultPublishMaxGaugeForHistogramsWhenNotSet() {
+		assertThat(this.properties.getPublishMaxGaugeForHistograms()).isNull();
+		assertThat(createAdapter().publishMaxGaugeForHistograms()).isTrue();
+	}
+
+	@Test
+	void whenDefaultPublishMaxGaugeForHistogramsIsSetAdapterUsesIt() {
+		this.properties.setPublishMaxGaugeForHistograms(false);
+		assertThat(createAdapter().publishMaxGaugeForHistograms()).isFalse();
+	}
+
+	@Test
+	void whenAggregationTemporalityIsSetToDeltaThenPublishMaxGaugeForHistogramsDefaultChanges() {
+		this.properties.setAggregationTemporality(AggregationTemporality.DELTA);
+		assertThat(createAdapter().publishMaxGaugeForHistograms()).isFalse();
+	}
+
 	private OtlpMetricsPropertiesConfigAdapter createAdapter() {
 		return new OtlpMetricsPropertiesConfigAdapter(this.properties, this.openTelemetryProperties,
 				this.connectionDetails, this.environment);