Merge branch 'preview-1/stabilization' into dev

# Conflicts:
#	build/dependencies.props

src/Microsoft.AspNetCore.Mvc.Razor.Extensions/NamespaceDirective.cs

@@ -85,7 +85,14 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
         {
             var directiveSource = NormalizeDirectory(directive.Source?.FilePath);
 
-            var baseNamespace = directive.Tokens.First().Content;
+            var baseNamespace = directive.Tokens.FirstOrDefault()?.Content;
+            if (string.IsNullOrEmpty(baseNamespace))
+            {
+                // The namespace directive was incomplete.
+                @namespace = string.Empty;
+                return false;
+            }
+
             if (string.IsNullOrEmpty(source) || directiveSource == null)
             {
                 // No sources, can't compute a suffix.

src/Microsoft.AspNetCore.Razor.Language/RazorTemplateEngine.cs

@@ -182,12 +182,6 @@ namespace Microsoft.AspNetCore.Razor.Language
             {
                 throw new ArgumentNullException(nameof(projectItem));
             }
-
-            if (!projectItem.Exists)
-            {
-                throw new InvalidOperationException(Resources.FormatRazorTemplateEngine_ItemCouldNotBeFound(projectItem.Path));
-            }
-
             var result = new List<RazorSourceDocument>();
 
 

test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Test/NamespaceDirectiveTest.cs

@@ -9,6 +9,48 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
 {
     public class NamespaceDirectiveTest
     {
+        [Fact]
+        public void TryComputeNamespace_IncompleteDirective_UsesEmptyNamespace()
+        {
+            // Arrange
+            var source = "c:\\foo\\bar\\bleh.cshtml";
+            var imports = "c:\\foo\\baz\\bleh.cshtml";
+            var node = new DirectiveIRNode()
+            {
+                Descriptor = NamespaceDirective.Directive,
+                Source = new SourceSpan(imports, 0, 0, 0, 0),
+            };
+
+            // Act
+            var computed = NamespaceDirective.TryComputeNamespace(source, node, out var @namespace);
+
+            // Assert
+            Assert.False(computed);
+            Assert.Equal(string.Empty, @namespace);
+        }
+
+        [Fact]
+        public void TryComputeNamespace_EmptyDirective_UsesEmptyNamespace()
+        {
+            // Arrange
+            var source = "c:\\foo\\bar\\bleh.cshtml";
+            var imports = "c:\\foo\\baz\\bleh.cshtml";
+            var node = new DirectiveIRNode()
+            {
+                Descriptor = NamespaceDirective.Directive,
+                Source = new SourceSpan(imports, 0, 0, 0, 0),
+            };
+            node.Children.Add(new DirectiveTokenIRNode() { Content = string.Empty });
+            node.Children[0].Parent = node;
+
+            // Act
+            var computed = NamespaceDirective.TryComputeNamespace(source, node, out var @namespace);
+
+            // Assert
+            Assert.False(computed);
+            Assert.Equal(string.Empty, @namespace);
+        }
+
         // When we don't have a relationship between the source file and the imports file
         // we will just use the namespace on the node directly.
         [Theory]

test/Microsoft.AspNetCore.Razor.Language.Test/RazorTemplateEngineTest.cs

@@ -11,6 +11,53 @@ namespace Microsoft.AspNetCore.Razor.Language
 {
     public class RazorTemplateEngineTest
     {
+        [Fact]
+        public void GetImports_CanQueryInformationOnNonExistentFileWithoutImports()
+        {
+            // Arrange
+            var project = new TestRazorProject();
+            var razorEngine = RazorEngine.Create();
+            var templateEngine = new RazorTemplateEngine(razorEngine, project)
+            {
+                Options =
+                {
+                    ImportsFileName = "MyImport.cshtml"
+                }
+            };
+            var projectItemToQuery = project.GetItem("/Views/Home/Index.cshtml");
+
+            // Act
+            var imports = templateEngine.GetImports(projectItemToQuery);
+
+            // Assert
+            Assert.Empty(imports);
+        }
+
+        [Fact]
+        public void GetImports_CanQueryInformationOnNonExistentFileWithImports()
+        {
+            // Arrange
+            var path = "/Views/Home/MyImport.cshtml";
+            var projectItem = new TestRazorProjectItem(path);
+            var project = new TestRazorProject(new[] { projectItem });
+            var razorEngine = RazorEngine.Create();
+            var templateEngine = new RazorTemplateEngine(razorEngine, project)
+            {
+                Options =
+                {
+                    ImportsFileName = "MyImport.cshtml"
+                }
+            };
+            var projectItemToQuery = project.GetItem("/Views/Home/Index.cshtml");
+
+            // Act
+            var imports = templateEngine.GetImports(projectItemToQuery);
+
+            // Assert
+            var import = Assert.Single(imports);
+            Assert.Equal(projectItem.Path, import.FileName);
+        }
+
         [Fact]
         public void GenerateCode_ThrowsIfItemCannotBeFound()
         {