Return response body in FeignException from errorReading (#2618)

core/src/main/java/feign/FeignException.java

@@ -177,13 +177,20 @@ public String contentUTF8() {
   }
 
   static FeignException errorReading(Request request, Response response, IOException cause) {
+    byte[] body = {};
+    try {
+      if (response.body() != null) {
+        body = Util.toByteArray(response.body().asInputStream());
+      }
+    } catch (IOException ignored) { // NOPMD
+    }
     return new FeignException(
         response.status(),
         format("%s reading %s %s", cause.getMessage(), request.httpMethod(), request.url()),
         request,
         cause,
-        request.body(),
-        request.headers());
+        body,
+        response.headers());
   }
 
   public static FeignException errorStatus(String methodKey, Response response) {

core/src/test/java/feign/AsyncFeignTest.java

@@ -621,7 +621,8 @@ void throwsFeignExceptionIncludingBody() throws Throwable {
     } catch (FeignException e) {
       assertThat(e.getMessage())
           .contains("timeout reading POST http://localhost:" + server.getPort() + "/");
-      assertThat(e.contentUTF8()).isEqualTo("Request body");
+      // After #2618 the FeignException carries the response body, not the request body.
+      assertThat(e.contentUTF8()).isEqualTo("success!");
       return;
     }
     fail("");

core/src/test/java/feign/FeignExceptionTest.java

@@ -43,16 +43,22 @@ void canCreateWithRequestAndResponse() {
             StandardCharsets.UTF_8,
             null);
 
+    Map<String, Collection<String>> responseHeaders =
+        Collections.singletonMap("content-type", Collections.singletonList("application/json"));
     Response response =
         Response.builder()
             .status(400)
             .body("response".getBytes(StandardCharsets.UTF_8))
+            .headers(responseHeaders)
             .request(request)
             .build();
 
     FeignException exception =
         FeignException.errorReading(request, response, new IOException("socket closed"));
     assertThat(exception.responseBody()).isNotEmpty();
+    // the exception must carry the response body, not the request body (gh-2618)
+    assertThat(exception.contentUTF8()).isEqualTo("response");
+    assertThat(exception.responseHeaders()).containsKeys("content-type");
     assertThat(exception.hasRequest()).isTrue();
     assertThat(exception.request()).isNotNull();
   }

core/src/test/java/feign/FeignTest.java

@@ -607,13 +607,14 @@ void throwsFeignExceptionIncludingBody() {
     } catch (FeignException e) {
       assertThat(e.getMessage())
           .isEqualTo("timeout reading POST http://localhost:" + server.getPort() + "/");
-      assertThat(e.contentUTF8()).isEqualTo("Request body");
+      // After #2618 the FeignException carries the response body, not the request body.
+      assertThat(e.contentUTF8()).isEqualTo("success!");
     }
   }
 
   @Test
   void throwsFeignExceptionWithoutBody() {
-    server.enqueue(new MockResponse().setBody("success!"));
+    server.enqueue(new MockResponse());
 
     TestInterface api =
         Feign.builder()

core/src/test/java/feign/FeignUnderAsyncTest.java

@@ -493,13 +493,14 @@ void throwsFeignExceptionIncludingBody() {
     } catch (FeignException e) {
       assertThat(e.getMessage())
           .isEqualTo("timeout reading POST http://localhost:" + server.getPort() + "/");
-      assertThat(e.contentUTF8()).isEqualTo("Request body");
+      // After #2618 the FeignException carries the response body, not the request body.
+      assertThat(e.contentUTF8()).isEqualTo("success!");
     }
   }
 
   @Test
   void throwsFeignExceptionWithoutBody() {
-    server.enqueue(new MockResponse().setBody("success!"));
+    server.enqueue(new MockResponse());
 
     TestInterface api =
         AsyncFeign.builder()

hc5/src/test/java/feign/hc5/AsyncApacheHttp5ClientTest.java

@@ -535,7 +535,8 @@ void throwsFeignExceptionIncludingBody() throws Throwable {
     } catch (final FeignException e) {
       assertThat(e.getMessage())
           .isEqualTo("timeout reading POST http://localhost:" + server.getPort() + "/");
-      assertThat(e.contentUTF8()).isEqualTo("Request body");
+      // After #2618 the FeignException carries the response body, not the request body.
+      assertThat(e.contentUTF8()).isEqualTo("success!");
       return;
     }
     fail("");

java11/src/test/java/feign/http2client/test/Http2ClientAsyncTest.java

@@ -529,7 +529,8 @@ void throwsFeignExceptionIncludingBody() throws Throwable {
     } catch (final FeignException e) {
       assertThat(e.getMessage())
           .isEqualTo("timeout reading POST http://localhost:" + server.getPort() + "/");
-      assertThat(e.contentUTF8()).isEqualTo("Request body");
+      // After #2618 the FeignException carries the response body, not the request body.
+      assertThat(e.contentUTF8()).isEqualTo("success!");
       return;
     }
     fail("");

okhttp/src/test/java/feign/okhttp/OkHttpClientAsyncTest.java

@@ -528,7 +528,8 @@ void throwsFeignExceptionIncludingBody() throws Throwable {
     } catch (final FeignException e) {
       assertThat(e.getMessage())
           .isEqualTo("timeout reading POST http://localhost:" + server.getPort() + "/");
-      assertThat(e.contentUTF8()).isEqualTo("Request body");
+      // After #2618 the FeignException carries the response body, not the request body.
+      assertThat(e.contentUTF8()).isEqualTo("success!");
       return;
     }
     fail("");