Fixing #2480 to produce an InvalidProjectException when attempting to publish a

project folder that does not contain a project.json file

src/Microsoft.DotNet.Cli.Utils/InvalidProjectException.cs

@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace Microsoft.DotNet.Cli.Utils
+{
+    public class InvalidProjectException : Exception
+    {
+        public InvalidProjectException() { }
+        public InvalidProjectException(string message) : base(message) { }
+        public InvalidProjectException(string message, Exception innerException) : base(message, innerException) { }
+    }
+}

src/dotnet/commands/dotnet-publish/PublishCommand.cs

@@ -412,6 +412,16 @@ namespace Microsoft.DotNet.Tools.Publish
 
         private IEnumerable<ProjectContext> SelectContexts(string projectPath, NuGetFramework framework, string runtime)
         {
+            if (projectPath.EndsWith("project.json"))
+            {
+                if (File.Exists(projectPath) == false)
+                    throw new InvalidProjectException($"'{projectPath}' does not exist");
+            }
+            else if (File.Exists(Path.Combine(projectPath, "project.json")) == false)
+            {
+                throw new InvalidProjectException($"'{projectPath}' does not contain a project.json file");
+            }
+
             var allContexts = framework == null ?
                 ProjectContext.CreateContextForEachFramework(projectPath) :
                 new[] { ProjectContext.Create(projectPath, framework) };

test/dotnet-publish.Tests/PublishTests.cs

@@ -294,5 +294,26 @@ namespace Microsoft.DotNet.Tools.Publish.Tests
             var command = new TestCommand(Path.Combine(publishedDir.FullName, outputExe));
             command.Execute("").Should().ExitWith(0);
         }
+
+        [Fact]
+        public void PublishFailsWhenProjectRootIsEmpty()
+        {
+            using (var dir = new DisposableDirectory(Temp))
+            {
+                var command = new TestCommand("dotnet");
+                command.Execute($"publish {dir.Path}").Should().Fail();
+            }
+        }
+
+        [Fact]
+        public void PublishFailsWhenProjectJsonDoesNotExist()
+        {
+            using (var dir = new DisposableDirectory(Temp))
+            {
+                var command = new TestCommand("dotnet");
+                string temp = Path.Combine(dir.Path, "project.json");
+                command.Execute($"publish {temp}").Should().Fail();
+            }
+        }
     }
 }