fix: close request bodies when HTTP client rejects before transport

httpc/client.go

@@ -88,11 +88,19 @@ func New(cfg Config) (*Client, error) {
 // consumed. Callers own response.Body. Only GET, HEAD and OPTIONS are retried,
 // and only when their bodies can be replayed. MaxRetries=0 disables retries.
 func (c *Client) Do(request *http.Request) (*http.Response, error) {
+	var requestError error
 	if c.closed.Load() {
-		return nil, ErrClosed
+		requestError = ErrClosed
+	} else if request == nil || request.URL == nil {
+		requestError = errors.New("httpc: nil request or URL")
 	}
-	if request == nil || request.URL == nil {
-		return nil, errors.New("httpc: nil request or URL")
+	if requestError != nil {
+		// Match http.Client.Do's ownership rule even when rejection happens
+		// before the underlying transport takes ownership of the body.
+		if request != nil && request.Body != nil {
+			_ = request.Body.Close()
+		}
+		return nil, requestError
 	}
 	ctx, cancel := context.WithTimeout(request.Context(), c.config.Timeout)
 	base := request.Clone(ctx)