add support for generating and including README.md in nuget package

Author: smdn

src/Smdn.Reflection.ReverseGenerating.ListApi.MSBuild.Tasks/Directory.Build.targets

@@ -6,5 +6,6 @@ SPDX-License-Identifier: MIT
   <ImportGroup>
     <Import Project="$(MSBuildThisFileDirectory)..\Directory.Build.targets" />
     <Import Project="$(MSBuildThisFileDirectory)UsingExportedTasks.targets" />
+    <Import Project="$(MSBuildThisFileDirectory)ReadmeFile.targets" />
   </ImportGroup>
 </Project>

src/Smdn.Reflection.ReverseGenerating.ListApi.MSBuild.Tasks/ReadmeFile.targets

@@ -0,0 +1,90 @@
+<!--
+SPDX-FileCopyrightText: 2022 smdn <smdn@smdn.jp>
+SPDX-License-Identifier: MIT
+-->
+<Project>
+  <PropertyGroup>
+    <PackageReadmeFile>README.md</PackageReadmeFile>
+    <NupkgReadmeFileOutputPath>$(OutputPath)$(PackageReadmeFile)</NupkgReadmeFileOutputPath>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <None Include="$(NupkgReadmeFileOutputPath)" Pack="true" PackagePath="$(PackageReadmeFile)" />
+  </ItemGroup>
+
+  <!-- overrides the target GenerateNupkgReadmeFile from Smdn.MSBuild.ProjectAssets.Library -->
+  <Target
+    Name="GenerateNupkgReadmeFile"
+    BeforeTargets="GenerateNuspec"
+  >
+    <ItemGroup>
+      <CoreAssemblyOutputs Include="$(OutputPath)**\Smdn*.dll"/>
+    </ItemGroup>
+
+    <GetCoreAssemblyInformationsFromLoadedAssembly AssemblyNames="%(CoreAssemblyOutputs.Filename)" Condition="'$(UseExportedTasksFromOutputAssembly)' == 'true'">
+      <Output TaskParameter="AssemblyInformations" ItemName="CoreAssemblyInformations" />
+    </GetCoreAssemblyInformationsFromLoadedAssembly>
+
+    <ItemGroup>
+      <_NupkgReadmeLines Include="# $(AssemblyName)" />
+      <_NupkgReadmeLines Include="$(Description)" />
+      <_NupkgReadmeLines Include="## Included tasks" />
+      <_NupkgReadmeLines Include="This package contains the following MSBuild tasks." />
+      <_NupkgReadmeLines Include="- `%(ExportTaskNames.Identity)`" />
+      <_NupkgReadmeLines Include="## Included assemblies" />
+      <_NupkgReadmeLines Include="This package contains the following assemblies." />
+      <_NupkgReadmeLines Include="- %(CoreAssemblyInformations.Identity) %(CoreAssemblyInformations.InformationalVersion)" />
+    </ItemGroup>
+
+    <WriteLinesToFile
+      File="$(NupkgReadmeFileOutputPath)"
+      Lines="@(_NupkgReadmeLines)"
+      Overwrite="true"
+    />
+  </Target>
+
+  <UsingTask
+    TaskName="GetCoreAssemblyInformationsFromLoadedAssembly"
+    TaskFactory="RoslynCodeTaskFactory"
+    AssemblyFile="$(MSBuildToolsPath)\Microsoft.Build.Tasks.Core.dll"
+  >
+    <ParameterGroup>
+      <AssemblyNames ParameterType="Microsoft.Build.Framework.ITaskItem[]" Required="true" />
+      <AssemblyInformations ParameterType="Microsoft.Build.Framework.ITaskItem[]" Output="true" />
+    </ParameterGroup>
+    <Task>
+      <Using Namespace="System" />
+      <Using Namespace="System.Linq" />
+      <Using Namespace="System.Reflection" />
+      <Using Namespace="System.Runtime.Versioning" />
+      <Code Type="Fragment" Language="cs"><![CDATA[
+        AssemblyInformations = AssemblyNames
+          .Select(item =>
+            AppDomain
+              .CurrentDomain
+              .GetAssemblies()
+              .First(assm => assm.GetName().Name == item.ItemSpec)
+          )
+          .Select(static assm =>
+            (
+              Name: assm.GetName().Name,
+              InformationalVersion: assm.GetCustomAttribute<AssemblyInformationalVersionAttribute>().InformationalVersion,
+              TargetFramework: assm.GetCustomAttribute<TargetFrameworkAttribute>().FrameworkName
+            )
+          )
+          .Distinct()
+          .OrderBy(static info => info.Name)
+          .Select(static info =>
+            new TaskItem(
+              info.Name,
+              new Dictionary<string, string>() {
+                { nameof(info.InformationalVersion), info.InformationalVersion },
+                { nameof(info.TargetFramework), info.TargetFramework }
+              }
+            )
+          )
+          .ToArray();
+      ]]></Code>
+    </Task>
+  </UsingTask>
+</Project>

src/Smdn.Reflection.ReverseGenerating.ListApi.MSBuild.Tasks/Smdn.Reflection.ReverseGenerating.ListApi.MSBuild.Tasks.csproj

@@ -10,6 +10,8 @@ SPDX-License-Identifier: MIT
     <VersionSuffix></VersionSuffix>
     <Nullable>enable</Nullable>
     <CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies>
+
+    <!-- suppress generating README.md by Smdn.MSBuild.ProjectAssets.Library -->
     <GeneratePackageReadmeFile>false</GeneratePackageReadmeFile>
   </PropertyGroup>