From db91a0386e0abf5cf8348fa8995e6ae42ca72d41 Mon Sep 17 00:00:00 2001
From: Stuart Douglas <stuart.w.douglas@gmail.com>
Date: Wed, 11 Aug 2021 12:40:16 +1000
Subject: [PATCH] Inject modified headers

Fixes #19317
---
 .../simple/SimpleQuarkusRestResource.java     |  5 +++--
 .../core/ResteasyReactiveRequestContext.java  | 21 +++++++++++++++----
 2 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/extensions/resteasy-reactive/quarkus-resteasy-reactive/deployment/src/test/java/io/quarkus/resteasy/reactive/server/test/simple/SimpleQuarkusRestResource.java b/extensions/resteasy-reactive/quarkus-resteasy-reactive/deployment/src/test/java/io/quarkus/resteasy/reactive/server/test/simple/SimpleQuarkusRestResource.java
index c1469854c42a1..e847095bb96f4 100644
--- a/extensions/resteasy-reactive/quarkus-resteasy-reactive/deployment/src/test/java/io/quarkus/resteasy/reactive/server/test/simple/SimpleQuarkusRestResource.java
+++ b/extensions/resteasy-reactive/quarkus-resteasy-reactive/deployment/src/test/java/io/quarkus/resteasy/reactive/server/test/simple/SimpleQuarkusRestResource.java
@@ -33,6 +33,7 @@
 import javax.ws.rs.core.Response;
 import javax.ws.rs.ext.Providers;
 
+import org.jboss.resteasy.reactive.RestHeader;
 import org.jboss.resteasy.reactive.server.SimpleResourceInfo;
 
 import io.quarkus.runtime.BlockingOperationControl;
@@ -138,8 +139,8 @@ public Response filters(@Context Providers providers) {
 
     @GET
     @Path("filters")
-    public Response filters(@Context HttpHeaders headers) {
-        return Response.ok().header("filter-request", headers.getHeaderString("filter-request")).build();
+    public Response filters(@Context HttpHeaders headers, @RestHeader("filter-request") String header) {
+        return Response.ok().header("filter-request", header).build();
     }
 
     @GET
diff --git a/independent-projects/resteasy-reactive/server/runtime/src/main/java/org/jboss/resteasy/reactive/server/core/ResteasyReactiveRequestContext.java b/independent-projects/resteasy-reactive/server/runtime/src/main/java/org/jboss/resteasy/reactive/server/core/ResteasyReactiveRequestContext.java
index f7cd8e532f01e..0b699f4ace735 100644
--- a/independent-projects/resteasy-reactive/server/runtime/src/main/java/org/jboss/resteasy/reactive/server/core/ResteasyReactiveRequestContext.java
+++ b/independent-projects/resteasy-reactive/server/runtime/src/main/java/org/jboss/resteasy/reactive/server/core/ResteasyReactiveRequestContext.java
@@ -10,6 +10,7 @@
 import java.net.URISyntaxException;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.Deque;
 import java.util.LinkedList;
 import java.util.List;
@@ -781,10 +782,22 @@ public void initPathSegments() {
 
     @Override
     public Object getHeader(String name, boolean single) {
-        if (single)
-            return serverRequest().getRequestHeader(name);
-        // empty collections must not be turned to null
-        return serverRequest().getAllRequestHeaders(name);
+        if (httpHeaders == null) {
+            if (single)
+                return serverRequest().getRequestHeader(name);
+            // empty collections must not be turned to null
+            return serverRequest().getAllRequestHeaders(name);
+        } else {
+            if (single)
+                return httpHeaders.getMutableHeaders().getFirst(name);
+            // empty collections must not be turned to null
+            List<String> list = httpHeaders.getMutableHeaders().get(name);
+            if (list == null) {
+                return Collections.emptyList();
+            } else {
+                return list;
+            }
+        }
     }
 
     @Override