Raise RestClientException for unknown status codes

HttpStatus cannot be created with an unknown status code. If a server
returns a status code that's not in the HttpStatus enum values, an
IllegalArgumentException is raised. Rather than allowing it to
propagate as such, this change ensures the actual exception raised is
a RestClientException.

Issue: SPR-9406

Author: rstoyanchev

spring-web/src/main/java/org/springframework/web/client/DefaultResponseErrorHandler.java

@@ -45,7 +45,18 @@ public class DefaultResponseErrorHandler implements ResponseErrorHandler {
 	 * Delegates to {@link #hasError(HttpStatus)} with the response status code.
 	 */
 	public boolean hasError(ClientHttpResponse response) throws IOException {
-		return hasError(response.getStatusCode());
+		return hasError(getStatusCode(response));
+	}
+
+	private HttpStatus getStatusCode(ClientHttpResponse response) throws IOException {
+		HttpStatus statusCode;
+		try {
+			statusCode = response.getStatusCode();
+		}
+		catch (IllegalArgumentException ex) {
+			throw new RestClientException("Unknown status code [" + response.getRawStatusCode() + "]");
+		}
+		return statusCode;
 	}
 
 	/**
@@ -69,7 +80,7 @@ protected boolean hasError(HttpStatus statusCode) {
 	 * and a {@link RestClientException} in other cases.
 	 */
 	public void handleError(ClientHttpResponse response) throws IOException {
-		HttpStatus statusCode = response.getStatusCode();
+		HttpStatus statusCode = getStatusCode(response);
 		HttpHeaders headers = response.getHeaders();
 		MediaType contentType = headers.getContentType();
 		Charset charset = contentType != null ? contentType.getCharSet() : null;

spring-web/src/test/java/org/springframework/web/client/DefaultResponseErrorHandlerTests.java

@@ -124,4 +124,16 @@ public void handleErrorNullResponse() throws Exception {
 
 		verify(response);
 	}
+
+	// SPR-9406
+
+	@Test(expected=RestClientException.class)
+	public void unknownStatusCode() throws Exception {
+		expect(response.getStatusCode()).andThrow(new IllegalArgumentException("No matching constant for 999"));
+		expect(response.getRawStatusCode()).andReturn(999);
+
+		replay(response);
+
+		handler.handleError(response);
+	}
 }

src/dist/changelog.txt

@@ -7,7 +7,7 @@ Changes in version 3.2 M2
 -------------------------
 
 * spring-test module now depends on junit:junit-dep
-
+* raise RestClientException instead of IllegalArgumentException for unknown status codes
 
 Changes in version 3.2 M1 (2012-05-28)
 --------------------------------------