Automatically set Link metadata on items outside the project folder

TestAssets/TestProjects/LinkTest/LinkTest/Class1.cs

@@ -0,0 +1,8 @@
+using System;
+
+namespace LinkTest
+{
+    public class Class1
+    {
+    }
+}

TestAssets/TestProjects/LinkTest/LinkTest/LinkTest.csproj

@@ -0,0 +1,63 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netstandard2.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup Condition="'$(IncludeWithGlob)' == 'true' And '$(UseLinkBase)' == 'true'">
+    <Compile Include="..\Linked\**\*.cs" LinkBase="Linked\Files" />
+    <AdditionalFiles Include="..\Linked\**\*.Additional.txt" LinkBase="Linked\Files" />
+    <None Include="..\Linked\**\*.None.txt" LinkBase="Linked\Files" />
+    <Content Include="..\Linked\**\*.Content.txt" LinkBase="Linked\Files" />
+    <EmbeddedResource Include="..\Linked\**\*.Embedded.txt" LinkBase="Linked\Files" />
+    <CustomItem Include="..\Linked\**\*.Custom.txt" LinkBase="Linked\Files" />
+  </ItemGroup>
+
+  <ItemGroup Condition="'$(IncludeWithGlob)' == 'true' And '$(UseLinkBase)' != 'true'">
+    <Compile Include="..\Linked\**\*.cs" />
+    <AdditionalFiles Include="..\Linked\**\*.Additional.txt" />
+    <None Include="..\Linked\**\*.None.txt" />
+    <Content Include="..\Linked\**\*.Content.txt" />
+    <EmbeddedResource Include="..\Linked\**\*.Embedded.txt" />
+    <CustomItem Include="..\Linked\**\*.Custom.txt" />
+  </ItemGroup>
+
+  <ItemGroup Condition="'$(IncludeWithGlob)' != 'true' And '$(UseLinkBase)' == 'true'">
+    <Compile Include="..\Linked\Linked.Class.cs" LinkBase="Linked\Files"/>
+    <AdditionalFiles Include="..\Linked\Linked.Additional.txt" LinkBase="Linked\Files"/>
+    <None Include="..\Linked\Linked.None.txt" LinkBase="Linked\Files"/>
+    <Content Include="..\Linked\Linked.Content.txt" LinkBase="Linked\Files"/>
+    <EmbeddedResource Include="..\Linked\Linked.Embedded.txt" LinkBase="Linked\Files"/>
+    <CustomItem Include="..\Linked\*Linked.Custom.txt" LinkBase="Linked\Files"/>
+  </ItemGroup>
+
+  <ItemGroup Condition="'$(IncludeWithGlob)' != 'true' And '$(UseLinkBase)' != 'true'">
+    <Compile Include="..\Linked\Linked.Class.cs"/>
+    <AdditionalFiles Include="..\Linked\Linked.Additional.txt" />
+    <None Include="..\Linked\Linked.None.txt" />
+    <Content Include="..\Linked\Linked.Content.txt" />
+    <EmbeddedResource Include="..\Linked\Linked.Embedded.txt" />
+    <CustomItem Include="..\Linked\*Linked.Custom.txt" />
+  </ItemGroup>
+
+
+  <Target Name="WriteItems" DependsOnTargets="Compile">
+    <ItemGroup>
+      <LinesToWrite Include="Compile%09%(Compile.FullPath)%09%(Compile.Link)" />
+      <LinesToWrite Include="AdditionalFiles%09%(AdditionalFiles.FullPath)%09%(AdditionalFiles.Link)" />
+      <LinesToWrite Include="None%09%(None.FullPath)%09%(None.Link)" />
+      <LinesToWrite Include="Content%09%(Content.FullPath)%09%(Content.Link)" />
+      <LinesToWrite Include="EmbeddedResource%09%(EmbeddedResource.FullPath)%09%(EmbeddedResource.Link)" />
+      <LinesToWrite Include="CustomItem%09%(CustomItem.FullPath)%09%(CustomItem.Link)" />
+    </ItemGroup>
+
+    <WriteLinesToFile
+      File="$(IntermediateOutputPath)\Items.txt"
+      Lines="@(LinesToWrite)"
+      Overwrite="true"
+      Encoding="Unicode"
+      />
+  </Target>
+
+
+</Project>

TestAssets/TestProjects/LinkTest/Linked/A/B C/Linked.Class.cs

@@ -0,0 +1,8 @@
+using System;
+
+namespace LinkTest
+{
+    public class LinkedSubClass
+    {
+    }
+}

TestAssets/TestProjects/LinkTest/Linked/Linked.Class.cs

@@ -0,0 +1,8 @@
+using System;
+
+namespace LinkTest
+{
+    public class LinkedClass
+    {
+    }
+}

src/Tasks/Microsoft.NET.Build.Tasks/build/Microsoft.NET.Sdk.DefaultItems.targets

@@ -101,6 +101,52 @@ Copyright (c) .NET Foundation. All rights reserved.
     <!-- Default to use the version of the framework runtime matching the target framework version-->
     <RuntimeFrameworkVersion Condition="'$(RuntimeFrameworkVersion)' == ''">$(_TargetFrameworkVersionWithoutV)</RuntimeFrameworkVersion>
   </PropertyGroup>
+
+  <!--
+    Automatically add Link metadata to items of specific types if they are outside of the project folder and don't already have the Link metadata set.
+    This will cause them to be shown in the Solution Explorer.  If an item has LinkBase metadata, the automatic Link will start with that value, and
+    the items will appear in the Solution Explorer under the folder specified by LinkBase.
+    -->
+  <ItemGroup Condition="'$(SetLinkMetadataAutomatically)' != 'false'">
+    <Compile Update="@(Compile)">
+      <!-- First, add a trailing slash to the LinkBase metadata if necessary.  This allows us to use the same value
+           for the Link metadata whether or not LinkBase metadata is set: %(LinkBase)%(RecursiveDir)%(Filename)%(Extension) 
+
+           Note that RecursiveDir already includes the trailing slash.
+      -->
+      <LinkBase Condition="'%(LinkBase)' != ''">$([MSBuild]::EnsureTrailingSlash(%(LinkBase)))</LinkBase>
+
+      <!-- Set the Link metadata if it's not already set and the item is outside of the project directory.
+           Check whether an item is inside the project directory by seeing if the FullPath starts with EnuserTrailingSlash(MSBuildProjectDirectory)
+           The FullPath and the MSBuildProjectDirectory will both already be normalized full paths.
+           The call to [MSBuild]::ValueOrDefault() is there in order to allow calling StartsWith on the FullPath value, since it's
+           not possible to call a string method on a metadata item directly.  The intrinsic ValueOrDefault() will be more
+           performant than calling String.Copy(), which has been used for this in other contexts, but actually makes a copy
+           of the string data.
+      -->    
+      <Link Condition="'%(Link)' == '' And !$([MSBuild]::ValueOrDefault('%(FullPath)', '').StartsWith($([MSBuild]::EnsureTrailingSlash($(MSBuildProjectDirectory)))))">%(LinkBase)%(RecursiveDir)%(Filename)%(Extension)</Link>
+    </Compile>
+
+    <AdditionalFiles Update="@(AdditionalFiles)">
+      <LinkBase Condition="'%(LinkBase)' != ''">$([MSBuild]::EnsureTrailingSlash(%(LinkBase)))</LinkBase>
+      <Link Condition="'%(Link)' == '' And !$([MSBuild]::ValueOrDefault('%(FullPath)', '').StartsWith($([MSBuild]::EnsureTrailingSlash($(MSBuildProjectDirectory)))))">%(LinkBase)%(RecursiveDir)%(Filename)%(Extension)</Link>
+    </AdditionalFiles>
+
+    <None Update="@(None)">
+      <LinkBase Condition="'%(LinkBase)' != ''">$([MSBuild]::EnsureTrailingSlash(%(LinkBase)))</LinkBase>
+      <Link Condition="'%(Link)' == '' And !$([MSBuild]::ValueOrDefault('%(FullPath)', '').StartsWith($([MSBuild]::EnsureTrailingSlash($(MSBuildProjectDirectory)))))">%(LinkBase)%(RecursiveDir)%(Filename)%(Extension)</Link>
+    </None>
+
+    <Content Update="@(Content)">
+      <LinkBase Condition="'%(LinkBase)' != ''">$([MSBuild]::EnsureTrailingSlash(%(LinkBase)))</LinkBase>
+      <Link Condition="'%(Link)' == '' And !$([MSBuild]::ValueOrDefault('%(FullPath)', '').StartsWith($([MSBuild]::EnsureTrailingSlash($(MSBuildProjectDirectory)))))">%(LinkBase)%(RecursiveDir)%(Filename)%(Extension)</Link>
+    </Content>
+
+    <EmbeddedResource Update="@(EmbeddedResource )">
+      <LinkBase Condition="'%(LinkBase)' != ''">$([MSBuild]::EnsureTrailingSlash(%(LinkBase)))</LinkBase>
+      <Link Condition="'%(Link)' == '' And !$([MSBuild]::ValueOrDefault('%(FullPath)', '').StartsWith($([MSBuild]::EnsureTrailingSlash($(MSBuildProjectDirectory)))))">%(LinkBase)%(RecursiveDir)%(Filename)%(Extension)</Link>
+    </EmbeddedResource >
+  </ItemGroup>
 
   <UsingTask TaskName="CheckForImplicitPackageReferenceOverrides" AssemblyFile="$(MicrosoftNETBuildTasksAssembly)" />
 

test/Microsoft.NET.Build.Tests/GivenThatWeWantToIncludeItemsOutsideTheProjectFolder.cs

@@ -0,0 +1,122 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+using System.Collections.Generic;
+using System.Text;
+using FluentAssertions;
+using Microsoft.NET.TestFramework;
+using Microsoft.NET.TestFramework.Assertions;
+using Microsoft.NET.TestFramework.Commands;
+using Xunit;
+
+using Xunit.Abstractions;
+using System.Xml.Linq;
+using System.IO;
+using System.Linq;
+
+namespace Microsoft.NET.Build.Tests
+{
+    public class GivenThatWeWantToIncludeItemsOutsideTheProjectFolder : SdkTest
+    {
+        public GivenThatWeWantToIncludeItemsOutsideTheProjectFolder(ITestOutputHelper log) : base(log)
+        {
+        }
+
+        //  Disabled on full framework MSBuild until CI machines have VS with bundled .NET Core / .NET Standard versions
+        //  See https://github.com/dotnet/sdk/issues/1077
+        [CoreMSBuildOnlyTheory]
+        [InlineData(false, false)]
+        [InlineData(false, true)]
+        [InlineData(true, false)]
+        [InlineData(true, true)]
+        public void Link_metadata_is_added_to_items_outside_the_project_folder(bool includeWithGlob, bool useLinkBase)
+        {
+            string identifier = (includeWithGlob ? "Globbed" : "Direct") + (useLinkBase ? "_LinkBase" : "");
+            var testAsset = _testAssetsManager
+                .CopyTestAsset("LinkTest", "LinkTest_", identifier)
+                .WithSource()
+                .WithProjectChanges(project =>
+                {
+                    var ns = project.Root.Name.Namespace;
+                    var propertyGroup = project.Root.Element(ns + "PropertyGroup");
+                    propertyGroup.Add(new XElement(ns + "IncludeWithGlob", includeWithGlob));
+                    propertyGroup.Add(new XElement(ns + "UseLinkBase", useLinkBase));
+                })
+                .Restore(Log, relativePath: "LinkTest");
+
+            var command = new MSBuildCommand(Log, "WriteItems", testAsset.TestRoot, "LinkTest");
+
+            command.Execute()
+                .Should()
+                .Pass();
+
+            string intermediateOutputPath = Path.Combine(command.GetBaseIntermediateDirectory().FullName, "Debug", "netstandard2.0");
+            string itemsFile = Path.Combine(intermediateOutputPath, "Items.txt");
+
+            var items = File.ReadAllLines(itemsFile)
+                .Select(l => l.Split('\t'))
+                .Select(f => (itemType: f[0], fullPath: f[1], link: f[2]))
+                .ToList();
+
+            var itemDict = items.GroupBy(i => i.itemType)
+                .ToDictionary(g => g.Key, g => g.Select(i => (fullPath: i.fullPath, link: i.link)).ToList());
+
+            //  Remove generated source files
+            itemDict["Compile"].RemoveAll(i =>
+            {
+                string filename = Path.GetFileName(i.fullPath);
+                return filename.Contains("AssemblyInfo") ||
+                        filename.Contains("AssemblyAttributes");
+            });
+
+            var expectedItems = new Dictionary<string, List<string>>()
+            {
+                ["Compile"] = new List<string>() { "Class1.cs", @"..\Linked\Linked.Class.cs" },
+                ["AdditionalFiles"] = new List<string>() { @"..\Linked\Linked.Additional.txt" },
+                ["None"] = new List<string>() { @"..\Linked\Linked.None.txt" },
+                ["Content"] = new List<string>() { @"..\Linked\Linked.Content.txt" },
+                ["EmbeddedResource"] = new List<string>() { @"..\Linked\Linked.Embedded.txt" },
+                ["CustomItem"] = new List<string>() { @"..\Linked\Linked.Custom.txt" },
+            };
+
+            if (includeWithGlob)
+            {
+                expectedItems["Compile"].Add(@"..\Linked\A\B C\Linked.Class.cs");
+                expectedItems["AdditionalFiles"].Add(@"..\Linked\A\B C\Linked.Additional.txt");
+                expectedItems["None"].Add(@"..\Linked\A\B C\Linked.None.txt");
+                expectedItems["Content"].Add(@"..\Linked\A\B C\Linked.Content.txt");
+                expectedItems["EmbeddedResource"].Add(@"..\Linked\A\B C\Linked.Embedded.txt");
+                expectedItems["CustomItem"].Add(@"..\Linked\A\B C\Linked.Custom.txt");
+            }
+
+            var projectFolder = Path.Combine(testAsset.TestRoot, "LinkTest");
+
+            var expectedItemMetadata = expectedItems.ToDictionary(
+                kvp => kvp.Key,
+                kvp => kvp.Value.Select(item =>
+                {
+                    string fullPath = Path.GetFullPath(Path.Combine(projectFolder, item.Replace('\\', Path.DirectorySeparatorChar)));
+                    string link = "";
+                    string linkedPrefix = @"..\Linked\";
+                    if (item.StartsWith(linkedPrefix) && kvp.Key != "CustomItem")
+                    {
+                        link = item.Substring(linkedPrefix.Length);
+                        if (useLinkBase)
+                        {
+                            link = @"Linked\Files\" + link;
+                        }
+                    }
+
+                    link = link.Replace('\\', Path.DirectorySeparatorChar);
+
+                    return (fullPath: fullPath, link: link);
+                }));
+
+            foreach (var itemType in expectedItemMetadata.Keys)
+            {
+                itemDict[itemType].Should().BeEquivalentTo(expectedItemMetadata[itemType]);
+            }
+        }
+    }
+}