Add Code Analyzers to Duality Core Source

[ilexp]

Summary

Switch the main development repository of Duality to Visual Studio 2015 to gain access to the new Analyzer feature and add some Analyzers to reduce reviewing workload on Pull Requests. This should not affect the minimum required version to develop plugins with Duality, only developing Duality itself will be upgraded. The framework version should not be changed.

Analysis

• Visual Studio 2015 should provide access to the Analyzers feature
• Code Analyzer availability is probably the main benefit of switching to VS 2015. This will allow to enforce coding style and other development guidelines and reduce the code review workload for new contributions.
• For Duality plugins, nothing should be changed. Users can switch versions as they prefer and compatibility should be a bigger concern. VS 2015 is still comparatively new and there is no good reason to enforce this as a minspec for framework users.
• Before doing this, make sure AppVeyor is able to compile Visual Studio 2015 projects and solutions. Edit: It's probably installed.

[ilexp]

Progress:

• Reviewed the available Analyzer ecosystem. A lot of them are big packages of rules where a large percentage isn't really usable for Duality or has never been a problem in code reviews, yet slows down compilation a lot. Some other rules that would have been expected or preferred do not exist.
• Right now, a custom set of Duality-specific Analyzers seems preferable. That way, specific rules that are derived from code review experiences can be written and maintained one at a time.

[ilexp]

Notes:

• Introduction to Analyzers
• Apparently, the default way to deploy custom code analyzers is via NuGet package. Since there is no dependency between the analyzers and Duality itself, it would be a viable option to completely split the two and have all the Analyzers in a different solution file, or maybe even repository.
  • The NuGet package requires a powershell script to register the Analyzer in the target project automatically, which isn't awesome.
  • It's optional, but that would mean having to manually add the Analyzer to each project file and adjust the links when updating. Not that great either - the powershell script is probably for the best.
• Having the Analyzer in the same solution as the analyzed projects doesn't work well since modifying the Analyzer will require a Visual Studio restart / re-open of the solution. Otherwise, the Analyzer will be out of order.

[ilexp]

Notes:

• Looking at the complexity of existing code style analzers, it seems like a bad idea to custom-write all required analyzers. Reconsider using existing style analzers.
  • Problem: stylecop.json appears to be ignored, or I just didn't find a way to make the Analyzer actually use it. Not sure what the problem was in my setup. Without the settings file, there is no way to switch it to requiring tabs for indentation.
  • Edit: Turns out, it's simply pre-release stuff that's not in the binaries yet.