First look at NDepend 3.0

I installed to today the latest version of NDepend and gave it a try. Last time I blogged about NDepend, I used it on a small solution, and while the generated report was full of useful information, I did not use the product at full strength, because as it’s name suggests, NDepend is about analyzing dependencies, and my solution was too small for interesting observations. This time I plan to analyze a large solution consisting of all of our projects with an exception of a Web administration projects that are not so interesting for such analysis. The solution file was generated using a utility described earlier and contains 140 projects. I never worked with such large solutions (usually I group projects in much smaller solutions), so I was a bit uncertain about how long it will take to load on my Dell D830 notebook. But it started up relatively quickly.

The biggest news about NDepend 3.0 is that it is now fully integrated into Visual Studio development environment. So now all its menus and windows are parts of development session, and windows of course can be docked.

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The very first impression from NDepend: it’s fast, blazingly fast. As you can see from the summary below, it used only 18 seconds to analyze 1188 source files in 140 projects of my solutions: 15 milliseconds on each file.

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So these are the metrics for my large solution, though I disagree with one detail: the report states that the solution has only 1 attribute class. Yes, it has only one class with .NET Attribute as its immediate parent, but there are several other classes that derive from Attribute, but not directly. One class derives from TypeMock.DecoratorAttribute that inherits from Attritbute. In addition there are several classes inheriting from PostSharp.Laos.OnMethodBoundaryAspect, and walking its inheritance tree brings us to MulticastAttribute that inherits from Attribute. I believe all such classes should be classified as attribute classes (since this is how they are used).

Enough with class attributes. I browsed the report and noticed that I’d like to change a few metrics’ parameters right away. For example, a list of too long type names included all types with names longer than 35 characters. While this seems to be a reasonable limit, some exclusions from such rule can also be reasonable. The top 10 entires in this list ended with either “Exception”, “Preset”, “Response” or “Request”. “Preset” is a suffix for a special category of classes that we use in tests, “Response”/”Request” are used in Web service communication, and “Exception” is of course a suffix for exceptions. I want to see classes with “really” long names, so how do I exclude these special classes from the rule?

It appeared to be very easy. I displayed a CQL Query Explorer and double-clicked on the rule. NDepend displayed a CQL Query Edit window, and it was obvious what I had to do to customize the rule. Below is an updated query:

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The simplicity of rule customization encouraged me to start inspecting other report’s details. One of the most important ones was the list of methods to refactor. And it also had to be customized. Because this is what I saw:

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Firstly, I think the table will look more informative if it highlights the figures that violates the metrics. Otherwise you have to browse every column and compare its data with the values from the respective CQL query. But what deserves customization is that the top of the list is occupied by class constructors with number of parameters exceeding recommended maximum (5). Should an exception be made for constructors? I believe it should, at least these days, when developers tend to use IoC containers and compose large applications with constructor injection. But how do I specify constructor exclusion? Luckily, I didn’t even have to browse NDepend online documentation – NDepend supports intellisense.

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Exclusion constructors from the query resulted in much more interesting list of methods (below). They are candidates for refactoring for different reasons: number of lines, number of IL instructions, netsing deptsh, number of variables, etc. Again, I would appreciate if offending figures were highlighted.

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It took me just minutes to apply these customizations, and what’s most encouraging is that I did not have to read anything about what these metrics are and how to adjust them to fit my needs: everything is intuitive, with additional explanation text shown along the queries and reports. I need more time to interpret metrics  and diagrams related to dependencies – the solution is too big to give a simple picture. I leave it to a second look. To be continued…

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