How does it work?

• To run at compile time, the tool is implemented as an MsBuild task so it runs regardless of whether it was invoked via Visual Studio or via MsBuild directly (eg. by a build server).
  • NsDepCop is invoked for every C# project but it performs an analysis only if it finds a config file (config.nsdepcop) next to the csproj file. Otherwise it doesn't do anything.
• To run the tool at code editing time it is implemented as a Roslyn DiagnosticAnalyzer which is invoked by and reports to the Visual Studio IDE.

• In the case of the MSBuild integration the parser can be Roslyn or NRefactory.
• In the case of the VisualStudio integration it is Roslyn.
• NsDepCop scans through the source code to find every type reference.
• Determines the namespaces of the referenced and referring types.
• Checks whether the namespace dependencies were allowed in the config.nsdepcop file.
• Reports disallowed dependencies.

The parts of NsDepCop

• NsDepCop.Core.dll
  • Config file handling and the core logic of the analysis implemented with both the NRefactory API and the Roslyn API.
• NsDepCop.MsBuildTask.dll
  • Implements a custom MSBuild task, and invokes the core analysis logic for the source files of a csproj.
• NsDepCop.ItemTemplate.zip
  • Visual Studio item template for the NsDepCop config file.
• NsDepCop.VisualStudioIntegration.dll
  • Implements a Roslyn DiagnosticAnalyzer and invokes the core analysis logic for the nodes that Roslyn handles to it.
• NsDepCop.vsix
  • Wraps the DiagnosticAnalyzer and the NsDepCop.ItemTemplate into a Visual Studio extension package.
• NsDepCop.msi
  • The setup package.
• NsDepCop.Setup.CustomActions.dll
  • Custom actions for the setup. The msbuild target file manipulation is implemented here.

Integration into the C# build process

• A custom MSBuild task can be integrated into the C# build process by adding an extra step into every csproj file or by adding it to Custom.After.Microsoft.CSharp.targets which is included by every csproj. NsDepCop does the latter.
• Setup injects the following tags into Custom.After.Microsoft.CSharp.targets:

<Projectxmlns="http://schemas.microsoft.com/developer/msbuild/2003"><UsingTaskAssemblyFile="NsDepCop.MsBuildTask.dll"TaskName="Codartis.NsDepCop.MsBuildTask.NsDepCopTask"/><PropertyGroup><BuildDependsOn>$(BuildDependsOn);NsDepCop</BuildDependsOn></PropertyGroup><TargetName="NsDepCop"><NsDepCopTaskReferencePath="@(ReferencePath)"Compile="@(Compile)"BaseDirectory="$(MSBuildProjectDirectory)"/></Target></Project>

• UsingTask: tells MsBuild which assembly implements the NsDepCop task.
• PropertyGroup/DependsOn: adds NsDepCop as an extra step to the BuildDependOn property group. So NsDepCop is the last task that executes right before the Build target.
• Target Name="NsDepCop": calls the NsDepCop custom MsBuild task and passes some parameters to it.
  • The ReferencePath item group contains all referenced assemblies.
  • The Compile item group contains all source files to be compiled.
  • BaseDirectory is the folder where the csproj file resides.
  • Parser (optional) is the name of the parser to use: NRefactory or Roslyn. Defaults to Roslyn.
  • InfoImportance (optional) specifies the info log events' message importance level: Low, Normal, High. Defaults to Normal.

Setup

• MSBuild 14 is required for all features.

• MSBuild integration
  • Installs to folder: (program files 32-bit)\MSBuild\v14.0
  • Installs NsDepCop, NRefactory and Roslyn files.
  • Creates or modifies this file with custom actions: Custom.After.Microsoft.CSharp.targets (see: Integration into the C# build process)
  • Installs the NsDepCopConfig.xsd into the Visual Studio schema cache folder.
• Visual Studio integration (VSIX)
  • Prereq: Visual Studio 2015
  • Installs a Visual Studio extension package: NsDepCop.vsix