Cross-Client no-op for legacy package reference #5444
Description
The secondary target of this feature is to unify the restore behavior among all our clients.
One can restore with NuGet.exe, open VS, and then auto-restore no-ops. When that, the user can build use msbuild /t:restore and that would no-op as well.
At this point that's not the case.
The dg spec generated for msbuild/nuget.exe/dotnet.exe case is not the same as the one generated by VS. Some of those inconsistencies have been resolved, while others haven't.
Here's a table of the presumed behavior (meaning, as far as we know, there might be some crazy scenarios in which this breaks, and when encountered, we'll want to fix them.
| Project Model | NuGet.Exe & VS Client | NuGet.exe & dotnet.exe | NuGet.exe & MsBuild | VS Client & dotnet.exe | VS Client & MsBuild | MsBuild & dotnet.exe |
|---|---|---|---|---|---|---|
| .NET Core - SDK based projects | Consistent | Consistent. | Consistent. | Consistent. | Consistent. | Consistent. |
| Legacy Package Reference projects | Inconsistent. | Consistent. | Consistent. | Inconsistent. | Consistent. | Inconsistent. |
| Project.Json | Inconsistent | Consistent. | Consistent. | Inconsistent. | Inconsistent. | Consistent. |