reverseproxy: On 103 don't delete own headers (#5091)

See #5074

1 files changed, 3 insertions, 2 deletions

diff --git a/modules/caddyhttp/reverseproxy/reverseproxy.go b/modules/caddyhttp/reverseproxy/reverseproxy.go
index 4c8b29b..55d3aa8 100644
--- a/modules/caddyhttp/reverseproxy/reverseproxy.go
+++ b/modules/caddyhttp/reverseproxy/reverseproxy.go
@@ -782,8 +782,9 @@ func (h *Handler) reverseProxy(rw http.ResponseWriter, req *http.Request, origRe
 				copyHeader(h, http.Header(header))
 				rw.WriteHeader(code)
 
-				// Clear headers, it's not automatically done by ResponseWriter.WriteHeader() for 1xx responses
-				for k := range h {
+				// Clear headers coming from the backend
+				// (it's not automatically done by ResponseWriter.WriteHeader() for 1xx responses)
+				for k := range header {
 					delete(h, k)
 				}