Grails would sometimes attempt to render the wrong view, particularly

during error dispatch. This was because certain information about the
view to render was stored in the request, and that was affecting whatever
was forwarded to. So while Grails would try to render the view associated
with an error action, suddenly it would end up rendering the original
one.

This fix clears certain request attributes before that request is
forwarded. This was already being done for includes, so I refactored
to share the code with the forwarding methods.

Conflicts:

	src/java/org/codehaus/groovy/grails/web/servlet/mvc/SimpleGrailsControllerHelper.java
	src/java/org/codehaus/groovy/grails/web/util/WebUtils.java

src/java/org/codehaus/groovy/grails/web/servlet/GrailsDispatcherServlet.java

@@ -338,7 +338,7 @@ public Locale getLocale() {
 
                         mv = super.processHandlerException(processedRequest, response, mappedHandler, e);
                         handlerException = e;
-                        render(mv, processedRequest, response);
+                        if (mv != null) render(mv, processedRequest, response);
                     }
                     else {
                         request.removeAttribute(GrailsApplicationAttributes.RENDERING_ERROR_ATTRIBUTE);

src/java/org/codehaus/groovy/grails/web/servlet/mvc/SimpleGrailsControllerHelper.java

@@ -384,14 +384,14 @@ public Object handleAction(GroovyObject controller,Closure action, HttpServletRe
     public ModelAndView handleActionResponse( GroovyObject controller,Object returnValue,String closurePropertyName, String viewName) {
         boolean viewNameBlank = (viewName == null || viewName.length() == 0);
         // reset the metaclass
-        ModelAndView explicityModelAndView = (ModelAndView)controller.getProperty(ControllerDynamicMethods.MODEL_AND_VIEW_PROPERTY);
+        ModelAndView explicitModelAndView = (ModelAndView)controller.getProperty(ControllerDynamicMethods.MODEL_AND_VIEW_PROPERTY);
 
         if (!webRequest.isRenderView()) {
             return null;
         }
 
-        if (explicityModelAndView != null) {
-            return explicityModelAndView;
+        if (explicitModelAndView != null) {
+            return explicitModelAndView;
         }
 
         if (returnValue == null) {

src/java/org/codehaus/groovy/grails/web/util/WebUtils.java

@@ -281,6 +281,12 @@ public static String forwardRequestForUrlMappingInfo(HttpServletRequest request,
         //populateParamsForMapping(info);
         RequestDispatcher dispatcher = request.getRequestDispatcher(forwardUrl);
 
+        // Clear the request attributes that affect view rendering. Otherwise
+        // whatever we forward to may render the wrong thing! Note that we
+        // don't care about the return value because we're delegating
+        // responsibility for rendering the response.
+        saveAndResetWebRequest(request, info);
+
         exposeForwardRequestAttributes(request);
         exposeRequestAttributes(request, model);
         dispatcher.forward(request, response);
@@ -303,42 +309,82 @@ public static IncludedContent includeForUrlMappingInfo(HttpServletRequest reques
         String includeUrl = buildDispatchUrlForMapping(info, true);
 
         final GrailsWebRequest webRequest = GrailsWebRequest.lookup(request);
-
-        String currentController = null;
-        String currentAction = null;
-        String currentId = null;
-        ModelAndView currentMv = null;
-        Map currentParams = null;
-        if (webRequest != null) {
-            currentController = webRequest.getControllerName();
-            currentAction = webRequest.getActionName();
-            currentId = webRequest.getId();
-            currentParams = new HashMap();
-            currentParams.putAll(webRequest.getParameterMap());
-            currentMv = (ModelAndView)webRequest.getAttribute(GrailsApplicationAttributes.MODEL_AND_VIEW, 0);
-        }
+        InternalSavedRequest savedRequest = null;
+
         try {
-            if (webRequest!=null) {
-                webRequest.getParameterMap().clear();
-                info.configure(webRequest);
-                webRequest.getParameterMap().putAll(info.getParameters());
-                webRequest.removeAttribute(GrailsApplicationAttributes.MODEL_AND_VIEW, 0);
-            }
+            savedRequest = saveAndResetWebRequest(request, info);
             return includeForUrl(includeUrl, request, response, model);
         }
         finally {
-            if (webRequest!=null) {
-                webRequest.getParameterMap().clear();
-                webRequest.getParameterMap().putAll(currentParams);
-                webRequest.setId(currentId);
-                webRequest.setControllerName(currentController);
-                webRequest.setActionName(currentAction);
-                if (currentMv != null) {
-                    webRequest.setAttribute(GrailsApplicationAttributes.MODEL_AND_VIEW, currentMv, 0);
+            if (savedRequest != null) {
+            	webRequest.getParameterMap().clear();
+            	webRequest.getParameterMap().putAll(savedRequest.getParameterMap());
+                webRequest.setId(savedRequest.getId());
+                webRequest.setControllerName(savedRequest.getController());
+                webRequest.setActionName(savedRequest.getAction());
+                if (savedRequest.getModelAndView() != null) {
+                    webRequest.setAttribute(GrailsApplicationAttributes.MODEL_AND_VIEW, savedRequest.getModelAndView(), 0);
                 }
             }
         }
     }
+
+    /**
+     * Saves the details of the current web request in an {@link InternalSavedRequest}
+     * instance, clears information related to view rendering from the request
+     * attributes, and returns the saved request.
+     * @param request The underlying HTTP request to process.
+     * @param info The URL mapping that should be applied to the request after
+     * the attributes have been cleared.
+     * @return The saved web request details.
+     */
+    public static InternalSavedRequest saveAndResetWebRequest(HttpServletRequest request, UrlMappingInfo info) {
+        final GrailsWebRequest webRequest = GrailsWebRequest.lookup(request);
+        InternalSavedRequest savedRequest = null;
+        if (webRequest != null) {
+            savedRequest = new InternalSavedRequest(
+                    webRequest.getControllerName(),
+                    webRequest.getActionName(),
+                    webRequest.getId(),
+                    webRequest.getParameterMap(),
+                    (ModelAndView) webRequest.getAttribute(GrailsApplicationAttributes.MODEL_AND_VIEW, 0));
+            webRequest.getParameterMap().clear();
+            info.configure(webRequest);
+            webRequest.getParameterMap().putAll(info.getParameters());
+            webRequest.removeAttribute(GrailsApplicationAttributes.MODEL_AND_VIEW, 0);
+        }
+
+        return savedRequest;
+    }
+
+    /**
+     * Simple class that stores a subset of information about a request, including
+     * the target controller and action, and the request parameters. Also stores
+     * information about any current ModelAndView that will be used to render the
+     * response.
+     */
+    private static class InternalSavedRequest {
+        private String controller;
+        private String action;
+        private String id;
+        private HashMap parameters;
+        private ModelAndView modelAndView;
+
+        public InternalSavedRequest(String controllerName, String actionName, String id, Map parameterMap, ModelAndView mv) {
+            this.controller = controllerName;
+            this.action = actionName;
+            this.id = id;
+            this.parameters = new HashMap(parameterMap);
+            this.modelAndView = mv;
+        }
+
+        public String getController() { return controller; }
+        public String getAction() { return action; }
+        public String getId() { return id; }
+        public Map getParameterMap() { return parameters; }
+        public ModelAndView getModelAndView() { return modelAndView; }
+    }
+
 
     /**
      * Includes the given URL returning the resulting content as a String