fix bug 562104, crash when subscribed to imap folder '/', r/sr=standard8

mailnews/imap/src/nsImapIncomingServer.cpp

@@ -1057,6 +1057,8 @@ NS_IMETHODIMP nsImapIncomingServer::PossibleImapMailbox(const nsACString& folder
   if (dupFolderPath.Last() == '/')
   {
     dupFolderPath.SetLength(dupFolderPath.Length()-1);
+    if (dupFolderPath.IsEmpty())
+      return NS_ERROR_FAILURE;
     // *** this is what we did in 4.x in order to list uw folder only
     // mailbox in order to get the \NoSelect flag
     explicitlyVerify = !(boxFlags & kNameSpace);
@@ -1165,7 +1167,8 @@ NS_IMETHODIMP nsImapIncomingServer::PossibleImapMailbox(const nsACString& folder
           (kPublicMailbox | kOtherUsersMailbox | kPersonalMailbox))), &parentIsNew);
       }
     }
-    hostFolder->CreateClientSubfolderInfo(dupFolderPath, hierarchyDelimiter,boxFlags, PR_FALSE);
+    rv = hostFolder->CreateClientSubfolderInfo(dupFolderPath, hierarchyDelimiter,boxFlags, PR_FALSE);
+    NS_ENSURE_SUCCESS(rv, rv);
     caseInsensitive = MsgLowerCaseEqualsLiteral(dupFolderPath, "inbox");
     a_nsIFolder->GetChildWithURI(uri, PR_TRUE, caseInsensitive, getter_AddRefs(child));
   }

mailnews/imap/test/unit/test_mailboxes.js

@@ -59,6 +59,16 @@ const gTestArray =
                    QueryInterface(Ci.nsIMsgImapMailFolder);
     newChild.updateFolderWithListener(null, UrlListener);
   },
+  function checkEmptyFolder() {
+    try {
+    let serverSink = gLocalServer.QueryInterface(Ci.nsIImapServerSink);
+      serverSink.possibleImapMailbox("/", '/', 0);
+    }
+    catch (ex) {
+      // we expect this to fail, but not crash or assert.
+    }
+    do_timeout_function(0, function(){doTest(++gCurTestNum)});
+  },
 ];
 
 function endTest()
@@ -80,7 +90,7 @@ function doTest(test)
 
     var testFn = gTestArray[test-1];
     // Set a limit of 10 seconds; if the notifications haven't arrived by then there's a problem.
-    do_timeout(10000, function(){
+    do_timeout_function(10000, function(){
         if (gCurTestNum == test) 
           do_throw("Notifications not received in 10000 ms for operation " + testFn.name + 
             ", current status is " + gCurrStatus);
@@ -113,6 +123,6 @@ var UrlListener =
     // This can happen with a bunch of synchronous functions grouped together, and
     // can even cause tests to fail because they're still waiting for the listener
     // to return
-    do_timeout(0, function(){doTest(++gCurTestNum)});
+    do_timeout_function(0, function(){doTest(++gCurTestNum)});
   }
 };