From 787aea5f3182f1c04f04427b39de79aaa641c58e Mon Sep 17 00:00:00 2001
From: Hector Sanjuan <code@hector.link>
Date: Mon, 4 Apr 2022 12:09:54 +0200
Subject: [PATCH] Always include the X-Stream-Error trailer (even without
 errors)

This is to potentially address things like this:

https://github.com/nodejs/undici/issues/432#issuecomment-1047931107
---
 api/common/api.go          | 4 ++++
 api/rest/client/request.go | 4 +++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/api/common/api.go b/api/common/api.go
index 094c439c..24c06096 100644
--- a/api/common/api.go
+++ b/api/common/api.go
@@ -644,6 +644,10 @@ func (api *API) StreamResponse(w http.ResponseWriter, next StreamIterator, errCh
 
 	if err != nil {
 		w.Header().Set("X-Stream-Error", err.Error())
+	} else {
+		// Due to some Javascript-browser-land stuff, we set the header
+		// even when there is no error.
+		w.Header().Set("X-Stream-Error", "")
 	}
 	// check for function errors
 	for funcErr := range errCh {
diff --git a/api/rest/client/request.go b/api/rest/client/request.go
index 0d80f888..98aaa943 100644
--- a/api/rest/client/request.go
+++ b/api/rest/client/request.go
@@ -156,7 +156,9 @@ func (c *defaultClient) handleStreamResponse(resp *http.Response, handler respon
 	trailerErrs := resp.Trailer.Values("X-Stream-Error")
 	var err error
 	for _, trailerErr := range trailerErrs {
-		err = multierr.Append(err, errors.New(trailerErr))
+		if trailerErr != "" {
+			err = multierr.Append(err, errors.New(trailerErr))
+		}
 	}
 
 	if err != nil {