Project 'XXXXXX' does not have a lock file. Please run "dotnet restore" to generate a new lock file

Question

I have ASP.NET Core Web API project and .Net Core Library project. The Web API has reference to Library project as target : project. Name of the library project is Transformations.
Below is the project.json for both the projects

project.json for Web API

"dependencies": {
   "Microsoft.NETCore.App": {
    "version": "1.0.0",
    "type": "platform"
  },
   "Microsoft.ApplicationInsights.AspNetCore": "1.0.0",
   "Microsoft.AspNetCore.Mvc": "1.0.0",
   "Microsoft.AspNetCore.Server.IISIntegration": "1.0.0",
   "Microsoft.AspNetCore.Server.Kestrel": "1.0.0",
   "Microsoft.Extensions.Configuration.EnvironmentVariables": "1.0.0",
   "Microsoft.Extensions.Configuration.FileExtensions": "1.0.0",
   "Microsoft.Extensions.Configuration.Json": "1.0.0",
   "Microsoft.Extensions.Logging": "1.0.0",
   "Microsoft.Extensions.Logging.Console": "1.0.0",
   "Microsoft.Extensions.Logging.Debug": "1.0.0",
   "Microsoft.Extensions.Options.ConfigurationExtensions": "1.0.0",
   "Transformations": {
            "target": "project"
    },
   "Microsoft.Extensions.DependencyInjection": "1.0.0",
   "Serilog.Extensions.Logging": "1.3.0-dev-10125",
   "Serilog.Sinks.RollingFile": "3.0.0",
   "Serilog.Settings.Configuration": "2.1.0",
   "Microsoft.AspNetCore.Diagnostics": "1.0.0"
},

project.json for Library project

{
  "version": "1.0.0-*",

  "dependencies": {
    "NETStandard.Library": "1.6.0",
    "Microsoft.Extensions.Options.ConfigurationExtensions": "1.0.0"
  },

  "frameworks": {
    "netstandard1.6": {
      "imports": "dnxcore50"
    }
  },
  "configurations": {
    "Production": {},
    "Staging": {}
  }
}

On the build server below is the project structure for Api & Transformation projects.

 D:\Jenkins\MyJenkinsProject\workspace\src\MySolution
                                                   \Api
                                                   \Transformation

On the build server I executed the following commands

  D:\Jenkins\MyJenkinsProject\workspace\src\MySolution\Api>dotnet restore

and then

  D:\Jenkins\MyJenkinsProject\workspace\src\MySolution\Api>dotnet build

I get error

Project Transformations does not have a lock file. Please run "dotnet restore" to generate a new lock file.

Now if I run the following the following commands in the order, then everything works fine.

  D:\Jenkins\MyJenkinsProject\workspace\src\MySolution\Transformation>dotnet restore
  D:\Jenkins\MyJenkinsProject\workspace\src\MySolution\Api>dotnet restore
  D:\Jenkins\MyJenkinsProject\workspace\src\MySolution\Api>dotnet build

Questions
1>When library is referenced as project in API project why do I need to run dotnet restore separately for library project? Why cant it restores referened project implicitly?

Answer 1

From Zlatko Knezevic:

This behavior is by design. […] If you wish to restore all of the dependencies for all your projects in one go, so to speak, just run dotnet restore at the root of your solution (where you have the global.json file).