`dotnet build` should call `dotnet restore` if project.json has changed

Today, dotnet build (and thus dotnet run) is separate from dotnet restore. I’d like to discuss having dotnet build (and thus dotnet run) detect if project.json has been modified since the last compilation, then perform a dotnet restore if project.json has been modified.

Two motivations:

1. It’s easy to forget to dotnet restore after you add a NuGet package, etc.
2. It would benefit VSCode, described in Issue dotnet/sdk#5312.

If this has already been proposed and closed, I couldn’t find the issue. What’s the rationale for them being separate?

[enricosada]

pls dont add too much magic, not everything has the same workflow.

maybe i need to run dotnet restore -f /path/to/my/packages or other command line args, instead of plain dotnet restore.

restore it’s a separate step from build. that’s it, is not too bad And the build is already too entangled to nuget (the restore), and is a pain to configure/extend

[livarcocc]

We are adding no-op restore for CLI 2.0.