Fail on Docker image load with empty response

In some cases, a call to the Docker image load API will fail but
return a 200 OK response status code and an empty response. This
commit detects that the response from this call is empty and
treats this condition as an error instead of a silent failure.

Fixes gh-23130

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/docker/DockerApi.java

@@ -178,11 +178,18 @@ public class DockerApi {
 			Assert.notNull(archive, "Archive must not be null");
 			Assert.notNull(listener, "Listener must not be null");
 			URI loadUri = buildUrl("/images/load");
+			StreamCaptureUpdateListener streamListener = new StreamCaptureUpdateListener();
 			listener.onStart();
 			try {
 				try (Response response = http().post(loadUri, "application/x-tar", archive::writeTo)) {
-					jsonStream().get(response.getContent(), LoadImageUpdateEvent.class, listener::onUpdate);
+					jsonStream().get(response.getContent(), LoadImageUpdateEvent.class, (event) -> {
+						streamListener.onUpdate(event);
+						listener.onUpdate(event);
+					});
 				}
+				Assert.state(StringUtils.hasText(streamListener.getCapturedStream()),
+						"Invalid response received when loading image "
+								+ ((archive.getTag() != null) ? "\"" + archive.getTag() + "\"" : ""));
 			}
 			finally {
 				listener.onFinish();
@@ -352,4 +359,22 @@ public class DockerApi {
 
 	}
 
+	/**
+	 * {@link UpdateListener} used to ensure an image load response stream.
+	 */
+	private static class StreamCaptureUpdateListener implements UpdateListener<LoadImageUpdateEvent> {
+
+		private String stream;
+
+		@Override
+		public void onUpdate(LoadImageUpdateEvent event) {
+			this.stream = event.getStream();
+		}
+
+		String getCapturedStream() {
+			return this.stream;
+		}
+
+	}
+
 }

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/test/java/org/springframework/boot/buildpack/platform/docker/DockerApiTests.java

@@ -50,6 +50,7 @@ import org.springframework.boot.buildpack.platform.io.TarArchive;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.BDDMockito.given;
@@ -172,6 +173,16 @@ class DockerApiTests {
 					.withMessage("Listener must not be null");
 		}
 
+		@Test // gh-23130
+		void loadWithEmptyResponseThrowsException() throws Exception {
+			Image image = Image.of(getClass().getResourceAsStream("type/image.json"));
+			ImageArchive archive = ImageArchive.from(image);
+			URI loadUri = new URI(IMAGES_URL + "/load");
+			given(http().post(eq(loadUri), eq("application/x-tar"), any())).willReturn(emptyResponse());
+			assertThatIllegalStateException().isThrownBy(() -> this.api.load(archive, this.loadListener))
+					.withMessageContaining("Invalid response received");
+		}
+
 		@Test
 		void loadLoadsImage() throws Exception {
 			Image image = Image.of(getClass().getResourceAsStream("type/image.json"));