Feature request: DisableImplicitTransitiveReferences

[jaredpar]

Implicit transitive references is a neat feature and definitely a benefit for the vast majority of projects out there. The feature is not free though and trying to enable it on dotnet/roslyn has caused me no end of headaches. In particular:

• VSIX #433: The VSSDK build tasks do not multi-targeting nor do they understand the new metadata the SDK is attaching to products. Before implicit transitive references this was fine because I didn't reveal my multi-targeted projects to the VSSDK. Now I can't avoid doing so. This issue can be worked around but is tedious.
• CreatePkgDef command line length: The CreatePkgDef command takes as an input on the command line all references a project contains. Implicit transitive references, via the NuGet graph explosion of references, puts so many references on the command line that it blows past the 32,000 character limit Windows supports
• RAR time: More references means more time spent in RAR. This causes a roughly 31% increase in build time for the Roslyn repo.

To work around this I think the SDK should support the ability to opt out of implicit transitive references.

<DisableImplicitTransitiveReferences>true</DisableImplicitTransitiveReferences>

This will make it significantly easier to adopt the SDK into existing projects.

Note: I'm aware you can unofficially disable this today by overriding the "IncludeTransitiveProjectReferences" target. That work around is unsupported and simply can't be done when using the new MSBuild file format + directory build props / targets.

[nguerrera]

This is a good idea. The name works for me too.

[KirillOsenkov]

Also there's little control over whether the assets "inherited" transitively will get copied to output or not. See this issue for details: NuGet/Home#5986