Support HttpComponents 5.6

This commit updates the HttpComponents HttpClient to refer to the parsed
`HttpEntity` for the content-related HTTP response headers such as
encoding and body length.

Closes gh-36100

framework-platform/framework-platform.gradle

@@ -94,8 +94,8 @@ dependencies {
 		api("org.apache.derby:derby:10.16.1.1")
 		api("org.apache.derby:derbyclient:10.16.1.1")
 		api("org.apache.derby:derbytools:10.16.1.1")
-		api("org.apache.httpcomponents.client5:httpclient5:5.5")
-		api("org.apache.httpcomponents.core5:httpcore5-reactive:5.3.5")
+		api("org.apache.httpcomponents.client5:httpclient5:5.6")
+		api("org.apache.httpcomponents.core5:httpcore5-reactive:5.4")
 		api("org.apache.poi:poi-ooxml:5.2.5")
 		api("org.apache.tomcat.embed:tomcat-embed-core:11.0.15")
 		api("org.apache.tomcat.embed:tomcat-embed-websocket:11.0.15")

spring-web/src/main/java/org/springframework/http/client/HttpComponentsClientHttpResponse.java

@@ -66,6 +66,16 @@ final class HttpComponentsClientHttpResponse implements ClientHttpResponse {
 	public HttpHeaders getHeaders() {
 		if (this.headers == null) {
 			MultiValueMap<String, String> adapter = new HttpComponentsHeadersAdapter(this.httpResponse);
+			// update headers if response is decompressed
+			HttpEntity httpEntity = this.httpResponse.getEntity();
+			if (httpEntity != null) {
+				if (httpEntity.getContentLength() == -1) {
+					adapter.remove(HttpHeaders.CONTENT_LENGTH);
+				}
+				if (httpEntity.getContentEncoding() == null) {
+					adapter.remove(HttpHeaders.CONTENT_ENCODING);
+				}
+			}
 			this.headers = HttpHeaders.readOnlyHttpHeaders(adapter);
 		}
 		return this.headers;

spring-web/src/test/java/org/springframework/http/client/HttpComponentsClientHttpRequestFactoryTests.java

@@ -18,6 +18,7 @@ package org.springframework.http.client;
 
 import java.io.InputStreamReader;
 import java.net.URI;
+import java.nio.charset.StandardCharsets;
 import java.time.Duration;
 import java.util.stream.Stream;
 
@@ -32,9 +33,11 @@ import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.MethodSource;
 
+import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
 import org.springframework.util.FileCopyUtils;
+import org.springframework.util.StreamUtils;
 
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static org.assertj.core.api.Assertions.assertThat;
@@ -60,6 +63,22 @@ class HttpComponentsClientHttpRequestFactoryTests extends AbstractHttpRequestFac
 		assertHttpMethod("patch", HttpMethod.PATCH);
 	}
 
+	@Test
+	void shouldDecompressWithExpectedHeaders() throws Exception {
+		ClientHttpRequest request = factory.createRequest(URI.create(baseUrl + "/compress/gzip"), HttpMethod.POST);
+		String message = "Hello World";
+		final byte[] body = message.getBytes(StandardCharsets.UTF_8);
+		StreamUtils.copy(body, request.getBody());
+
+		try (ClientHttpResponse response = request.execute()) {
+			assertThat(response.getStatusCode()).as("Invalid status code").isEqualTo(HttpStatus.OK);
+			String result = FileCopyUtils.copyToString(new InputStreamReader(response.getBody()));
+			assertThat(result).as("Invalid body").isEqualTo(message);
+			assertThat(response.getHeaders().get(HttpHeaders.CONTENT_ENCODING)).isNull();
+			assertThat(response.getHeaders().getContentLength()).isEqualTo(-1);
+		}
+	}
+
 	@Test
 	void assertCustomConfig() throws Exception {
 		HttpClient httpClient = HttpClientBuilder.create().build();