Azure: Merge ContextAccessor service registrations in shaded bundle

azure-bundle/build.gradle

@@ -42,6 +42,7 @@ project(":iceberg-azure-bundle") {
   shadowJar {
     archiveClassifier.set(null)
     zip64 true
+    mergeServiceFiles()
 
     // include the LICENSE and NOTICE files for the shaded Jar
     from(projectDir) {
@@ -54,6 +55,13 @@ project(":iceberg-azure-bundle") {
     relocate 'com.fasterxml.jackson', 'org.apache.iceberg.azure.shaded.com.fasterxml.jackson'
   }
 
+  test {
+    useJUnitPlatform()
+    dependsOn shadowJar
+    inputs.file shadowJar.archiveFile
+    systemProperty 'azure.test.bundle.jar', shadowJar.archiveFile.get().asFile.absolutePath
+  }
+
   jar {
     enabled = false
   }

azure-bundle/src/test/java/org/apache/iceberg/azure/TestAzureBundle.java

@@ -0,0 +1,53 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * 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 org.apache.iceberg.azure;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import org.junit.jupiter.api.Test;
+
+// this test ensures the azure bundle service registrations contain all entries across all bundled
+// deps. For ContextAccessor specifically, we expect entries from reactor core and reactor netty
+class TestAzureBundle {
+
+  @Test
+  void shadowJar_containsAllContextAccessorServiceRegistrations() throws IOException {
+    String bundlePath = System.getProperty("azure.test.bundle.jar");
+    assertThat(bundlePath).as("Azure bundle path").isNotNull();
+
+    try (JarFile bundle = new JarFile(new File(bundlePath))) {
+      JarEntry serviceDescriptor =
+          bundle.getJarEntry("META-INF/services/io.micrometer.context.ContextAccessor");
+      assertThat(serviceDescriptor).as("ContextAccessor service descriptor").isNotNull();
+
+      try (InputStream input = bundle.getInputStream(serviceDescriptor)) {
+        assertThat(new String(input.readAllBytes(), UTF_8).split("\\R"))
+            .contains(
+                "reactor.netty.contextpropagation.ChannelContextAccessor",
+                "reactor.util.context.ReactorContextAccessor");
+      }
+    }
+  }
+}