Now This is Visual Debugging!

Yesterday I installed a novel Visual Studio debugging tool from Microsoft Research and Brown University called Debugger Canvas. I started playing with it and was immediately hooked; now this is visual debugging! Debugger Canvas augments the default debugging experience in VS and gives you an interactive visual graph showing the call stack stack and code path. Each node in the tree contains the source code for each function. It even respects your font and layout preferences!

As you step through the code, the active line is highlighted as usual, and “Step Over” and “Step Into” also work as you would expect; if you step over a call, a new node is not created. Once a function has been stepped into it remains on the canvas even when the call returns, building up a visual representation of the code path. All the regular VS debugging windows and features work as expected, e.g hovering over a variable will show its current value.

Another cool feature is the ability to take snapshots of the value of a variable and then optionally display that on the canvas as a visual history. You can also annotate the canvas with “sticky” notes. The canvas itself is a file so you can save it for later use or you can save the file as an XPS document. I can imagine that test engineers will love this; it will allow them to reproduce a defect and then capture the full code path, pertinent variable history and their annotations, and then attach the resulting document to the bug in their defect management system.

There are a bunch of other features, including a “trial feature” that allows you to edit the code directly on the canvas (though apparently the code is a little buggy still). If during a debugging session you tire of Debugger Canvas you can just open a source file and continue debugging using the default debugging capabilities of VS.

I hope Debugger Canvas makes it into the next release of VS. You can download Debugger Canvas from Microsoft's DevLabs site.