Code review comment for lp:~edwin-grubbs/launchpad/bug-490659-series-timeout

I don't like the __len__ introduction as it blurs the line between lists and resultsets more : and we suffer because the line is blurry already. I realise you probably have a stack of stuff to put on top of this that is doing lens : however I'm worried about the knock on effects of the change : we should do it in IResultSet if we're doing it at all, not piecemeal on DecoratedResultSet. You could use a lazr.delegates to add __len__ just to your specific case (or, and perhaps better?) work up the stack replacing listified stuff with resultset aware code.

Other than that I think this is conceptually fine and an appropriate solution.

I'm a tad rusty on my plpython gotchas, so I'll let Stuart review that for you.