When we had a project.json without frameworks, we were failing to show the appropriate error message because when we were generating the error message itself we tried to access the project context (which requires a framework in the PJ). This fix makes the ProjectContext optional to add the migration error.

TestAssets/TestProjects/TestLibraryWithProjectFileWithoutFrameworks/project.json

@@ -0,0 +1,8 @@
+{
+    "dependencies": {
+        "Microsoft.VisualStudio.Web.CodeGeneration.Tools" : {
+            "version": "1.0.0-preview2-final",
+            "type": "build"
+        }
+    }
+}

src/Microsoft.DotNet.ProjectJsonMigration/MigrationRuleInputs.cs

@@ -24,7 +24,7 @@ namespace Microsoft.DotNet.ProjectJsonMigration
         {
             get
             {
-                return ProjectContexts.First();
+                return ProjectContexts.FirstOrDefault();
             }
         }
 

src/Microsoft.DotNet.ProjectJsonMigration/ProjectMigrator.cs

@@ -55,7 +55,7 @@ namespace Microsoft.DotNet.ProjectJsonMigration
                     {
                         new ProjectMigrationReport(
                             rootSettings.ProjectDirectory,
-                            rootInputs?.DefaultProjectContext.GetProjectName(),
+                            rootInputs?.DefaultProjectContext?.GetProjectName(),
                             new List<MigrationError> {e.Error},
                             null)
                     });
@@ -193,7 +193,7 @@ namespace Microsoft.DotNet.ProjectJsonMigration
         {
             if (!projectContexts.Any())
             {
-                MigrationErrorCodes.MIGRATE1013($"No projects found in {projectDirectory}").Throw();
+                MigrationErrorCodes.MIGRATE1013($"The project.json specifies no target frameworks in {projectDirectory}").Throw();
             }
 
             var defaultProjectContext = projectContexts.First();

test/Microsoft.DotNet.ProjectJsonMigration.Tests/GivenAProjectMigrator.cs

@@ -16,7 +16,7 @@ namespace Microsoft.DotNet.ProjectJsonMigration.Tests
     public class GivenAProjectMigrator : TestBase
     {
         [Fact]
-        public void It_copies_ProjectDirectory_contents_to_OutputDirectory_when_the_directories_are_different()
+        public void ItCopiesProjectDirectoryContentsToOutputDirectoryWhenTheDirectoriesAreDifferent()
         {
             var testProjectDirectory = TestAssetsManager
                 .CreateTestInstance("PJTestAppSimple", callingMethod: "z")
@@ -39,7 +39,7 @@ namespace Microsoft.DotNet.ProjectJsonMigration.Tests
         }
 
         [Fact]
-        public void It_has_error_when_migrating_a_deprecated_projectJson()
+        public void ItHasErrorWhenMigratingADeprecatedProjectJson()
         {
             var testProjectDirectory =
                 TestAssetsManager.CreateTestInstance("TestLibraryWithDeprecatedProjectFile", callingMethod: "z")
@@ -60,7 +60,7 @@ namespace Microsoft.DotNet.ProjectJsonMigration.Tests
         }
 
         [Fact]
-        public void It_has_error_when_migrating_a_non_csharp_app()
+        public void ItHasErrorWhenMigratingANonCsharpApp()
         {
             var testProjectDirectory =
                 TestAssetsManager.CreateTestInstance("FSharpTestProjects/TestApp", callingMethod: "z")
@@ -77,6 +77,32 @@ namespace Microsoft.DotNet.ProjectJsonMigration.Tests
             errorMessage.Should().Contain("MIGRATE20013::Non-Csharp App: Cannot migrate project");
         }
 
+        [Fact]
+        public void ItHasErrorWhenMigratingAProjectJsonWithoutAFrameworks()
+        {
+            var testAppName = "TestLibraryWithProjectFileWithoutFrameworks";
+            var testInstance = TestAssets.Get(testAppName)
+                .CreateInstance(testAppName)
+                .WithSourceFiles();
+
+            var testProjectDirectory = testInstance.Root.FullName;
+
+            var mockProj = ProjectRootElement.Create();
+            var testSettings = MigrationSettings.CreateMigrationSettingsTestHook(
+                testProjectDirectory,
+                testProjectDirectory,
+                mockProj);
+
+            var projectMigrator = new ProjectMigrator(new FakeEmptyMigrationRule());
+            var report = projectMigrator.Migrate(testSettings);
+
+            var projectReport = report.ProjectMigrationReports.First();
+
+            var errorMessage = projectReport.Errors.First().GetFormattedErrorMessage();
+            errorMessage.Should().Contain("MIGRATE1013::No Project:");
+            errorMessage.Should().Contain($"The project.json specifies no target frameworks in {testProjectDirectory}");
+        }
+
         private IEnumerable<string> EnumerateFilesWithRelativePath(string testProjectDirectory)
         {
             return