Add SPDisposeCheck to Visual Studio External Tools

In Episode 16 of SharePoint Pod Show, Todd Bleeker had a great SPDisposeCheck tip that bears repeating: add it to your Visual Studio External Tools!

Tools > External Tools > Add

SPDisposeCheck as VS External Tool

Here’s some output from the included example solution:

SPDisposeCheck Output in VS

My warning against overdependence notwithstanding, this really is a tool that should be run against any object model code.

Of course, Todd had a lot more to say than just this tip, and the whole show is definitely worth a listen. I will disagree on one point though: I wouldn’t consider returning an SPSite or SPWeb from a helper method to be a “false positive”. Sure, you can document the behavior, but it’s much easier to maintain over time if these objects are always created and disposed in the same place (if only because you can use using). I have yet to see an example where this sort of helper pattern couldn’t be refactored out into something more manageable.

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SPDisposeCheck Is Not A Shortcut

If you’re a SharePoint developer and you haven’t heard about the release of SPDisposeCheck, there are a number of blogs (like the SharePoint Team) you should be reading instead of (or hopefully in addition to) mine. Everyone is understandably enthusiastic—memory management is important and the rules are tricky. However, I’m afraid this is being viewed as something it’s not. To quote Tony Bierman‘s comment on Paul’s post:

I think there should be a “SPDisposeCheck Certified” logo.  This badge could be placed on the download pages and in the documentation of both free software and commercial software products as an indication of quality and adherence to best practices.

Let’s be clear: SPDisposeCheck is not definitive. It is a static analysis tool tuned to specific rules documented on the often-cited Patterns By Example. That post has been through perhaps a dozen iterations in the last year, updated as recently as last week. The team has no doubt put a lot of work into it (thanks for that), but there’s no reason to expect the guidance won’t be changed again.

Furthermore, there are countless perfectly safe code patterns, the so-called “false positives”, that will be reported as leaks. The documentation cites SPContext.Web.Site as an example, and I could probably rattle off a dozen more if pressed to do so. If the developer doesn’t investigate and just “fixes” every warning with using, more harm is done than good!

The tool will certainly be updated with the latest guidance, and the false positives will be addressed over time, but the core problem still remains: SPDisposeCheck will never know your code as well as you should. I’m sure thousands of leaks will be fixed because of it, and I’m not trying to diminish its value as part of a developer’s toolbox. Just don’t get caught thinking that passing SPDisposeCheck is a substitute for knowing what you’re doing.

That said, a big thanks to Roger, Stefan, Paul and the rest of the SPDisposeCheck team for their efforts to improve their documentation and the quality of our custom code.