Fix missing URI template from client observations in ResTemplateAdapter

Prior to this commit, the `RestTemplateAdapter` would manually expand
templated URIs. This means that the `RestTemplate` instance itself would
never see the templated URIs and could not record it in the client
observations at runtime.

This commit ensures that when URI templates are available, the adapter
uses the correct `exchange` method variant.

Fixes gh-31144

spring-web/src/main/java/org/springframework/web/client/support/RestTemplateAdapter.java

@@ -16,10 +16,8 @@
 
 package org.springframework.web.client.support;
 
-import java.net.URI;
 import java.util.ArrayList;
 import java.util.List;
-import java.util.Map;
 
 import org.springframework.core.ParameterizedTypeReference;
 import org.springframework.http.HttpCookie;
@@ -41,6 +39,7 @@ import org.springframework.web.service.invoker.HttpServiceProxyFactory;
  * {@link HttpServiceProxyFactory} configured with the given {@link RestTemplate}.
  *
  * @author Olga Maciaszek-Sharma
+ * @author Brian Clozel
  * @since 6.1
  */
 public final class RestTemplateAdapter implements HttpExchangeAdapter {
@@ -84,23 +83,21 @@ public final class RestTemplateAdapter implements HttpExchangeAdapter {
 	}
 
 	private RequestEntity<?> newRequest(HttpRequestValues values) {
-		URI uri;
+		HttpMethod httpMethod = values.getHttpMethod();
+		Assert.notNull(httpMethod, "HttpMethod is required");
+
+		RequestEntity.BodyBuilder builder;
+
 		if (values.getUri() != null) {
-			uri = values.getUri();
+			builder = RequestEntity.method(httpMethod, values.getUri());
 		}
 		else if (values.getUriTemplate() != null) {
-			String uriTemplate = values.getUriTemplate();
-			Map<String, String> variables = values.getUriVariables();
-			uri = this.restTemplate.getUriTemplateHandler().expand(uriTemplate, variables);
+			builder = RequestEntity.method(httpMethod, values.getUriTemplate(), values.getUriVariables());
 		}
 		else {
 			throw new IllegalStateException("Neither full URL nor URI template");
 		}
 
-		HttpMethod httpMethod = values.getHttpMethod();
-		Assert.notNull(httpMethod, "HttpMethod is required");
-
-		RequestEntity.BodyBuilder builder = RequestEntity.method(httpMethod, uri);
 		builder.headers(values.getHeaders());
 
 		if (!values.getCookies().isEmpty()) {

spring-web/src/test/java/org/springframework/web/client/support/RestClientAdapterTests.java

@@ -22,15 +22,17 @@ import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 import java.net.URI;
 import java.util.Optional;
+import java.util.function.BiFunction;
 import java.util.stream.Stream;
 
+import io.micrometer.observation.tck.TestObservationRegistry;
+import io.micrometer.observation.tck.TestObservationRegistryAssert;
 import okhttp3.mockwebserver.MockResponse;
 import okhttp3.mockwebserver.MockWebServer;
 import okhttp3.mockwebserver.RecordedRequest;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.MethodSource;
 
-import org.springframework.cglib.core.internal.Function;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
@@ -62,6 +64,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  *
  * @author Olga Maciaszek-Sharma
  * @author Rossen Stoyanchev
+ * @author Brian Clozel
  */
 @SuppressWarnings("JUnitMalformedDeclaration")
 class RestClientAdapterTests {
@@ -75,44 +78,49 @@ class RestClientAdapterTests {
 
 	public static Stream<Object[]> arguments() {
 		return Stream.of(
-				args(url -> {
-					RestClient restClient = RestClient.builder().baseUrl(url).build();
+				args((url, observationRegistry) -> {
+					RestClient restClient = RestClient.builder().baseUrl(url).observationRegistry(observationRegistry).build();
 					return RestClientAdapter.create(restClient);
 				}),
-				args(url -> {
+				args((url, observationRegistry) -> {
 					RestTemplate restTemplate = new RestTemplate();
+					restTemplate.setObservationRegistry(observationRegistry);
 					restTemplate.setUriTemplateHandler(new DefaultUriBuilderFactory(url));
 					return RestTemplateAdapter.create(restTemplate);
 				}));
 	}
 
 	@SuppressWarnings("resource")
-	private static Object[] args(Function<String, HttpExchangeAdapter> adapterFactory) {
+	private static Object[] args(BiFunction<String, TestObservationRegistry, HttpExchangeAdapter> adapterFactory) {
 		MockWebServer server = new MockWebServer();
 
 		MockResponse response = new MockResponse();
 		response.setHeader("Content-Type", "text/plain").setBody("Hello Spring!");
 		server.enqueue(response);
 
-		HttpExchangeAdapter adapter = adapterFactory.apply(server.url("/").toString());
+		TestObservationRegistry observationRegistry = TestObservationRegistry.create();
+
+		HttpExchangeAdapter adapter = adapterFactory.apply(server.url("/").toString(), observationRegistry);
 		Service service = HttpServiceProxyFactory.builderFor(adapter).build().createClient(Service.class);
 
-		return new Object[] { server, service };
+		return new Object[] { server, service, observationRegistry };
 	}
 
 
 	@ParameterizedAdapterTest
-	void greeting(MockWebServer server, Service service) throws Exception {
+	void greeting(MockWebServer server, Service service, TestObservationRegistry observationRegistry) throws Exception {
 		String response = service.getGreeting();
 
 		RecordedRequest request = server.takeRequest();
 		assertThat(response).isEqualTo("Hello Spring!");
 		assertThat(request.getMethod()).isEqualTo("GET");
 		assertThat(request.getPath()).isEqualTo("/greeting");
+		TestObservationRegistryAssert.assertThat(observationRegistry).hasObservationWithNameEqualTo("http.client.requests")
+				.that().hasLowCardinalityKeyValue("uri", "/greeting");
 	}
 
 	@ParameterizedAdapterTest
-	void greetingById(MockWebServer server, Service service) throws Exception {
+	void greetingById(MockWebServer server, Service service, TestObservationRegistry observationRegistry) throws Exception {
 		ResponseEntity<String> response = service.getGreetingById("456");
 
 		RecordedRequest request = server.takeRequest();
@@ -120,10 +128,12 @@ class RestClientAdapterTests {
 		assertThat(response.getBody()).isEqualTo("Hello Spring!");
 		assertThat(request.getMethod()).isEqualTo("GET");
 		assertThat(request.getPath()).isEqualTo("/greeting/456");
+		TestObservationRegistryAssert.assertThat(observationRegistry).hasObservationWithNameEqualTo("http.client.requests")
+				.that().hasLowCardinalityKeyValue("uri", "/greeting/{id}");
 	}
 
 	@ParameterizedAdapterTest
-	void greetingWithDynamicUri(MockWebServer server, Service service) throws Exception {
+	void greetingWithDynamicUri(MockWebServer server, Service service, TestObservationRegistry observationRegistry) throws Exception {
 		URI dynamicUri = server.url("/greeting/123").uri();
 		Optional<String> response = service.getGreetingWithDynamicUri(dynamicUri, "456");
 
@@ -131,6 +141,8 @@ class RestClientAdapterTests {
 		assertThat(response.orElse("empty")).isEqualTo("Hello Spring!");
 		assertThat(request.getMethod()).isEqualTo("GET");
 		assertThat(request.getRequestUrl().uri()).isEqualTo(dynamicUri);
+		TestObservationRegistryAssert.assertThat(observationRegistry).hasObservationWithNameEqualTo("http.client.requests")
+				.that().hasLowCardinalityKeyValue("uri", "none");
 	}
 
 	@ParameterizedAdapterTest