[undertow-dev] Undertow doesn't write cookie to response

Copy/pasted from https://developer.jboss.org/message/932789?et=watches.email.thread#932789. Any help would be appreciated... I'm trying to migrate an application from JBoss 7,.2.0.Final to WildFly 8.2.0.Final, and I find that some cookies are not written to the servlet response. I've tracked it down to io.undertow.servlet.spec.HttpServletResponseImpl.addCookie(). 1. @Override 2. public void addCookie(final Cookie cookie) { 3. if (insideInclude) { 4. return; 5. } 6. final ServletCookieAdaptor servletCookieAdaptor = new ServletCookieAdaptor(cookie); 7. if (cookie.getVersion() == 0) { 8. servletCookieAdaptor.setVersion(servletContext.getDeployment().getDeploymentInfo().getDefaultCookieVersion()); 9. } 10. exchange.setResponseCookie(servletCookieAdaptor); 11. } Apparently the insideCookie flag has been set to true at the point we're calling HttpServletResponse.addCookie(), so WildFly/Undertow just quietly throws it away and leaves me scratching my head trying to figure out what went wrong. When I search back up the call stack I see that our servlet is including a JSP page in its response like this 1. RequestDispatcher dispatcher = getServletContext().getRequestDispatcher(page); 2. dispatcher.include(state.getRequest(), state.getResponse()); So, it makes sense that insideInclude is true, since the code that's trying to set the cookie is being called from inside RequestDispatcher.include(), but I don't understand why WildFly/Undertow just arbitrarily throws it away. - See more at: https://developer.jboss.org/message/932789?et=watches.email.thread#932789