Failing first request and successfully retrying carries error from fi…

…rst (#290)

* Failing the first request and successfully retrying carries error from first
* The error itself should be nil, not the assertion of it
* Clear Error on Success

middleware.go

@@ -330,6 +330,7 @@ func parseResponseBody(c *Client, res *Response) (err error) {
 	if IsJSONType(ct) || IsXMLType(ct) {
 		// HTTP status code > 199 and < 300, considered as Result
 		if res.IsSuccess() {
+			res.Request.Error = nil
 			if res.Request.Result != nil {
 				err = Unmarshalc(c, ct, res.body, res.Request.Result)
 				return

resty_test.go

@@ -81,6 +81,16 @@ func createGetServer(t *testing.T) *httptest.Server {
 					_, _ = fmt.Fprintf(w, "%d", uint64(sinceLastRequest))
 				}
 				atomic.AddInt32(&attempt, 1)
+
+			case "/set-retry-error-recover":
+				w.Header().Set(hdrContentTypeKey, "application/json; charset=utf-8")
+				if atomic.LoadInt32(&attempt) == 0 {
+					w.WriteHeader(http.StatusTooManyRequests)
+					_, _ = w.Write([]byte(`{ "message": "too many" }`))
+				} else {
+					_, _ = w.Write([]byte(`{ "message": "hello" }`))
+				}
+				atomic.AddInt32(&attempt, 1)
 			case "/set-timeout-test-with-sequence":
 				seq := atomic.AddInt32(&sequence, 1)
 				time.Sleep(time.Second * 2)

retry_test.go

@@ -559,6 +559,37 @@ func TestClientRetryPost(t *testing.T) {
 	}
 }
 
+func TestClientRetryErrorRecover(t *testing.T) {
+	ts := createGetServer(t)
+	defer ts.Close()
+
+	c := dc().
+		SetRetryCount(2).
+		SetError(AuthError{}).
+		AddRetryCondition(
+			func(r *Response, _ error) bool {
+				err, ok := r.Error().(*AuthError)
+				retry := ok && r.StatusCode() == 429 && err.Message == "too many"
+				return retry
+			},
+		)
+
+	resp, err := c.R().
+		SetHeader(hdrContentTypeKey, "application/json; charset=utf-8").
+		SetJSONEscapeHTML(false).
+		SetResult(AuthSuccess{}).
+		Get(ts.URL + "/set-retry-error-recover")
+
+	assertError(t, err)
+
+	authSuccess := resp.Result().(*AuthSuccess)
+
+	assertEqual(t, http.StatusOK, resp.StatusCode())
+	assertEqual(t, "hello", authSuccess.Message)
+
+	assertNil(t, resp.Error())
+}
+
 func filler(*Response, error) bool {
 	return false
 }