fix: Fixed functions of decodeJson do not return.

Author: hechenglong

response.go

@@ -265,7 +265,7 @@ func (r *Response) wrapCopyReadCloser() {
 		f: func(b *bytes.Buffer) {
 			r.bodyBytes = append([]byte{}, b.Bytes()...)
 			closeq(r.Body)
-			r.Body = &nopReadCloser{r: bytes.NewReader(r.bodyBytes)}
+			r.Body = io.NopCloser(bytes.NewReader(r.bodyBytes))
 			releaseBuffer(b)
 		},
 	}

stream_test.go

@@ -0,0 +1,44 @@
+package resty
+
+import (
+	"bytes"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestDecodeJSONWhenResponseBodyIsNull(t *testing.T) {
+	r := &Response{
+		Body: io.NopCloser(bytes.NewReader([]byte("null"))),
+	}
+	r.wrapCopyReadCloser()
+	err := r.readAll()
+	assertNil(t, err)
+
+	var result map[int]int
+	err = decodeJSON(r.Body, &result)
+	assertNil(t, err)
+	assertNil(t, result)
+}
+
+func TestGetMethodWhenResponseIsNull(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Write([]byte("null"))
+	}))
+
+	client := New().SetRetryCount(3).EnableGenerateCurlCmd()
+
+	var x any
+	resp, err := client.R().SetBody("{}").
+		SetHeader("Content-Type", "application/json; charset=utf-8").
+		SetForceResponseContentType("application/json").
+		SetAllowMethodGetPayload(true).
+		SetResponseBodyUnlimitedReads(true).
+		SetResult(&x).
+		Get(server.URL + "/test")
+
+	assertNil(t, err)
+	assertEqual(t, "null", resp.String())
+	assertEqual(t, nil, x)
+}