Fix issue introduced with earlier WW-4873 fix:

- Fixes error 500 processing failures for double-submit results with TokenSessionStoreInterceptor processing
- Fix to InvocationSessionStore, new unit test confirming fix in InvocationSessionStoreTest
- Minor whitespace fix to TokenSessionStoreInterceptor

core/src/main/java/org/apache/struts2/interceptor/TokenSessionStoreInterceptor.java

@@ -126,11 +126,12 @@ public class TokenSessionStoreInterceptor extends TokenInterceptor {
             params.remove(tokenName);
             params.remove(TokenHelper.TOKEN_NAME_FIELD);
 
-			String sessionTokenName = TokenHelper.buildTokenSessionAttributeName(tokenName);
+            String sessionTokenName = TokenHelper.buildTokenSessionAttributeName(tokenName);
             ActionInvocation savedInvocation = InvocationSessionStore.loadInvocation(sessionTokenName, token);
 
             if (savedInvocation != null) {
                 // set the valuestack to the request scope
+                // Note: loadInvocation() restored invocation's PageContext (as savedInvocation's will already be closed)
                 ValueStack stack = savedInvocation.getStack();
                 request.setAttribute(ServletActionContext.STRUTS_VALUESTACK_KEY, stack);
 
@@ -158,8 +159,8 @@ public class TokenSessionStoreInterceptor extends TokenInterceptor {
         // we know the token name and token must be there
         String key = TokenHelper.getTokenName();
         String token = TokenHelper.getToken(key);
-		String sessionTokenName = TokenHelper.buildTokenSessionAttributeName(key);
-		InvocationSessionStore.storeInvocation(sessionTokenName, token, invocation);
+        String sessionTokenName = TokenHelper.buildTokenSessionAttributeName(key);
+        InvocationSessionStore.storeInvocation(sessionTokenName, token, invocation);
 
         return invocation.invoke();
     }

core/src/main/java/org/apache/struts2/util/InvocationSessionStore.java

@@ -20,6 +20,7 @@ package org.apache.struts2.util;
 
 import com.opensymphony.xwork2.ActionContext;
 import com.opensymphony.xwork2.ActionInvocation;
+import org.apache.struts2.ServletActionContext;
 
 import java.io.Serializable;
 import java.util.HashMap;
@@ -57,9 +58,22 @@ public class InvocationSessionStore {
 
         ActionInvocation savedInvocation = null;
         if (invocationContext.invocation != null) {
+            // WW-5026 - Preserve the previous PageContext (even if null) and restore it to the
+            // ActionContext after loading the savedInvocation context.  The saved context's PageContext
+            // would already be closed at this point (causing failures if used for output).
+            final ActionContext savedActionContext;
+            final ActionContext previousActionContext;
             savedInvocation = invocationContext.invocation;
-            ActionContext.setContext(savedInvocation.getInvocationContext());
-            ActionContext.getContext().setValueStack(savedInvocation.getStack());
+            savedActionContext = savedInvocation.getInvocationContext();
+            previousActionContext = ActionContext.getContext();
+            ActionContext.setContext(savedActionContext);
+            savedActionContext.setValueStack(savedInvocation.getStack());
+            savedActionContext.setValueStack(savedInvocation.getStack());
+            if (previousActionContext != null) {
+                savedActionContext.put(ServletActionContext.PAGE_CONTEXT, previousActionContext.get(ServletActionContext.PAGE_CONTEXT));
+            } else {
+                savedActionContext.put(ServletActionContext.PAGE_CONTEXT, null);
+            }
         }
 
         return savedInvocation;

core/src/test/java/org/apache/struts2/util/InvocationSessionStoreTest.java

@@ -31,6 +31,8 @@ import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 import java.util.HashMap;
 import java.util.Map;
+import org.apache.struts.mock.MockPageContext;
+import org.apache.struts2.ServletActionContext;
 
 
 /**
@@ -100,6 +102,35 @@ public class InvocationSessionStoreTest extends StrutsInternalTestCase {
         assertNull(savedInvocation);//Currently we don't support invocation restore from serialized session
     }
 
+    public void testStoreAndLoadPreservesPageContext() {
+        ActionContext actionContext = ActionContext.getContext();
+
+        // Create mock PageContext to put with the saved context (simulating a PageContext previously
+        // used and closed after generating JSP output).
+        MockPageContext mockSavedPageContext = new MockPageContext();
+        actionContext.put(ServletActionContext.PAGE_CONTEXT, mockSavedPageContext);
+        assertEquals(mockSavedPageContext, ActionContext.getContext().get(ServletActionContext.PAGE_CONTEXT));
+
+        InvocationSessionStore.storeInvocation(INVOCATION_KEY, TOKEN_VALUE, invocation);
+
+        ActionContext actionContext2 = new ActionContext(new HashMap<String, Object>());
+        actionContext2.setSession(session);
+        ActionContext.setContext(actionContext2);
+        assertEquals(actionContext2, ActionContext.getContext());
+
+        // Create mock PageContext to put with the current context (simulating a PageContext 
+        // associated with the current (active) process flow).  In real-world processing it
+        // will usually be null, but if non-null it should be preserved/restored upon load of the
+        // saved context.
+        MockPageContext mockPreviousPageContext = new MockPageContext();
+        actionContext2.put(ServletActionContext.PAGE_CONTEXT, mockPreviousPageContext);
+        assertEquals(mockPreviousPageContext, ActionContext.getContext().get(ServletActionContext.PAGE_CONTEXT));
+
+        InvocationSessionStore.loadInvocation(INVOCATION_KEY, TOKEN_VALUE);
+        assertEquals(actionContext, ActionContext.getContext());
+        assertEquals(mockPreviousPageContext, ActionContext.getContext().get(ServletActionContext.PAGE_CONTEXT));
+    }
+
     protected void setUp() throws Exception {
         super.setUp();
         stack = ActionContext.getContext().getValueStack();