CoreCLR: avoid project.json for simple cases

[tjanczuk]

@lstratman The CoreCLR requirement for project.json even for the simplest of scenarios is in rather stark contrast to the experience Node users are used to. Is there a reasonable way of avoiding this requirement? Can the project.json be specified imperatively via an API, perhaps one that covers at least the built-in dependencies: https://github.com/tjanczuk/edge-cs/blob/master/src/edge-cs-coreclr/EdgeCompiler.cs#L67-L74?

[lstratman]

That should be possible, yes. We actually already add a loader for the compiler's project.json (https://github.com/tjanczuk/edge/blob/master/src/CoreCLREmbedding/coreclrembedding.cs#L259-L268), but without a project.json for the application itself, it throws an exception before it can reach that point. We can distribute the project.json for Edge.js itself (https://github.com/tjanczuk/edge/blob/master/src/CoreCLREmbedding/project.json), run dnu restore on it during install like we do when we're in Linux, and then, in the EdgeAssemblyLoadContext constructor when we detect that there's no project.lock.json, we can add a loader for the "stock" project.lock.json that should allow them to run just about anything that doesn't require any external libraries. I'll experiment with this a bit tomorrow.

[tjanczuk]

Perfect, that would be a much better user experience!

[cmatskas]

Great question and an even better answer. I look forward seeing this implemented