Default PackagePath for PackageFile with no special folder to relative

Files that have special dirs like `build`, `tools`, etc., need special
treatment when resolving their TF-specific paths or not.

For those that aren't "special" (None, the default), we should provide
a smarter default that honors the relative dir instead of dumping everything
on the root.

Fixes NuGet/Home#5148

Author: kzu

src/Build/NuGet.Build.Packaging.Tasks/AssignPackagePath.cs

@@ -125,9 +125,15 @@ ITaskItem EnsurePackagePath(ITaskItem file, IDictionary<string, string> kindMap)
 			// P2P references)
 			var targetPath = file.GetMetadata("TargetPath");
 			if (string.IsNullOrEmpty(targetPath))
-				targetPath = file.GetMetadata("FileName") + file.GetMetadata("Extension");
+			{
+				targetPath = kind == PackageItemKind.None ? 
+					// For None, preserve the relative dir. 
+					file.GetMetadata("RelativeDir") + file.GetMetadata("FileName") + file.GetMetadata("Extension") :
+					file.GetMetadata("FileName") + file.GetMetadata("Extension");
+			}
 
-			// None files or those for which we know no mapping, go straight to the root folder of the package.
+			// None files or those for which we know no mapping, go straight to the root folder of the package, 
+			// respecting their RelativeDir.
 			// This allows custom packaging paths such as "workbooks", "docs" or whatever, which aren't prohibited by 
 			// the format.
 			var packagePath = string.IsNullOrEmpty(packageFolder) ?

src/Build/NuGet.Build.Packaging.Tasks/NuGet.Build.Packaging.Tasks.csproj

@@ -9,7 +9,7 @@
     <TargetExt>.dll</TargetExt>
     <StartupObject>NuGet.Build.Packaging.Program</StartupObject>
     <PackOnBuild Condition="'$(PackOnBuild)' == '' And '$(Configuration)' == 'Release'">true</PackOnBuild>
-	  <PackageOutputPath Condition="'$(PackageOutputPath)' == ''">..\..\..\out</PackageOutputPath>
+    <PackageOutputPath Condition="'$(PackageOutputPath)' == ''">..\..\..\out</PackageOutputPath>
   </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
@@ -64,7 +64,6 @@
     <Content Include="GenerateReferenceAssembly.csproj">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </Content>
-    <None Include="project.json" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\..\external\ApiIntersect\ApiIntersect\ApiIntersect.csproj">

src/Build/NuGet.Build.Packaging.Tests/AssignPackagePathTests.cs

@@ -442,19 +442,19 @@ public void when_assigning_content_file_with_additional_metadata_then_preserves_
 		}
 
 		[Fact]
-		public void when_file_has_none_kind_then_assigned_file_has_empty_package_folder()
+		public void when_file_has_none_kind_then_assigned_file_has_empty_package_folder_and_relative_package_path()
 		{
 			var task = new AssignPackagePath
 			{
 				BuildEngine = engine,
 				Kinds = kinds,
 				Files = new ITaskItem[]
 				{
-					new TaskItem("readme.txt", new Metadata
-					{
+					new TaskItem(@"content\docs\readme.txt", new Metadata
+					{						
 						{ "PackageId", "A" },
 						{ "TargetFrameworkMoniker", ".NETFramework,Version=v4.5" },
-						{ "Kind", "None" }
+						{ "Kind", "None" },
 					})
 				}
 			};
@@ -463,7 +463,7 @@ public void when_file_has_none_kind_then_assigned_file_has_empty_package_folder(
 			Assert.Contains(task.AssignedFiles, item => item.Matches(new
 			{
 				PackageFolder = "",
-				PackagePath = "readme.txt",
+				PackagePath = @"content\docs\readme.txt",
 			}));
 		}
 

src/Build/NuGet.Build.Packaging.Tests/given_a_library_with_project_reference.cs

@@ -21,7 +21,7 @@ public given_a_library_with_project_reference(ITestOutputHelper output)
 		[Fact]
 		public void when_getting_package_contents_then_retrieves_main_assembly_transitively()
 		{
-			var result = Builder.BuildScenario(nameof(given_a_library_with_project_reference), output: output, verbosity: LoggerVerbosity.Diagnostic);
+			var result = Builder.BuildScenario(nameof(given_a_library_with_project_reference), output: output);
 
 			result.AssertSuccess(output);