When DOM node of nsIAccessNode object hans't children/siblings/parent then corresponding method of nsIAccessNode throws exception. F.x. For <input type="text"/> accInput.firstChildNode throws exception since <input/> hasn't any child. Probably the behavious is used somewhere but on the first sight it confuse. I guess more appropriate behaviour is navigate methods will return null instead exception throwing.

Similar to bug 347019. The a11y module uses error codes wrong. Alexander, would you like to take these?

Comment on attachment 253609 [details] [diff] [review] patch r+ if you add the line: *aAccessNode = nsnull; at the top of each of these methods. Need to clear it out, otherwise this code will crash: nsIAccessNode *myNode; if (NS_SUCCEEDED(origNode->GetFirstChildNode(&myNode))) { myNode->Foo(); }

(In reply to comment #4) > (From update of attachment 253609 [details] [diff] [review]) > r+ if you add the line: > *aAccessNode = nsnull; at the top of each of these methods. > > Need to clear it out, otherwise this code will crash: > nsIAccessNode *myNode; > if (NS_SUCCEEDED(origNode->GetFirstChildNode(&myNode))) { > myNode->Foo(); > } > Is it better to do it inside MakeAccessNode method?

(In reply to comment #5) > Is it better to do it inside MakeAccessNode method? > Aaron, what about this?

That would be smaller code, but I like to null out out parameters before anything else happens. Habit taught by Brendan Eich. You can't go wrong that way.