Stub out a task to validate cascading version effects (#557)

build/repo.targets

@@ -57,12 +57,13 @@
 
   <Target Name="CloneRepositories" DependsOnTargets="_PrepareRepositories">
     <ItemGroup>
+      <_CloneRepositories Include="@(Repository);@(VerifyRepositories)" />
       <_CloneRepository Include="$(MSBuildProjectFullPath)">
         <AdditionalProperties>
-          CloneRepository=%(Repository.Identity);
-          CloneUrl=%(Repository.CloneUrl);
-          CloneBranch=%(Repository.Branch);
-          CloneRepositoryCommit=%(Repository.Commit);
+          CloneRepository=%(_CloneRepositories.Identity);
+          CloneUrl=%(_CloneRepositories.CloneUrl);
+          CloneBranch=%(_CloneRepositories.Branch);
+          CloneRepositoryCommit=%(_CloneRepositories.Commit);
           UseGateBranch=$(UseGateBranch)
         </AdditionalProperties>
       </_CloneRepository>
@@ -110,12 +111,22 @@
       Condition="'$(CloneRepositoryCommit)'!=''" />
   </Target>
 
+  <Target Name="PrepareBuildGraph" DependsOnTargets="_PrepareRepositories">
+    <RepoTasks.VerifyBuildGraph
+      BuildRepositories="@(Repositories)"
+      NoBuildRepositories="@(VerifyRepositories)">
+
+      <!-- TODO pass this into the PinVersion step -->
+      <Output TaskParameter="PackagesToBeProduced" ItemName="PackagesToBeProduced" />
+    </RepoTasks.VerifyBuildGraph>
+  </Target>
+
   <Target Name="BuildRepositories"
      DependsOnTargets="_PrepareRepositories;_FindDotNetPath;_CreateRepositoriesListWithCommits;_UpdateNuGetConfig;_GenerateBuildGraph;_BuildRepositories" />
 
   <Target Name="_PrepareRestoreGraphSpecs" DependsOnTargets="_PrepareRepositories">
     <ItemGroup>
-      <Solution Include="$(_CloneRepositoryRoot)%(Repository.Identity)\*.sln">
+      <Solution Include="$(_CloneRepositoryRoot)%(_CloneRepositories.Identity)\*.sln">
         <Repository>%(Repository.Identity)</Repository>
       </Solution>
 

build/tasks/RepoTasks.tasks

@@ -4,4 +4,5 @@
   </PropertyGroup>
 
   <UsingTask TaskName="RepoTasks.CalculateBuildGraph" AssemblyFile="$(_RepoTaskAssembly)" />
-</Project>
+  <UsingTask TaskName="RepoTasks.VerifyBuildGraph" AssemblyFile="$(_RepoTaskAssembly)" />
+</Project>

build/tasks/VerifyBuildGraph.cs

@@ -0,0 +1,37 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Microsoft.Build.Framework;
+using Microsoft.Build.Utilities;
+
+namespace RepoTasks
+{
+    public class VerifyBuildGraph : Task
+    {
+        /// <summary>
+        /// Repositories that we are building new versions of.
+        /// </summary>
+        [Required]
+        public ITaskItem[] BuildRepositories { get; set; }
+
+        /// <summary>
+        /// Repos that have already been build and released. We don't compile and build them,
+        /// but we still want to be sure their packages are accounted for in our graph calculations.
+        /// </summary>
+        public ITaskItem[] NoBuildRepositories { get; set; }
+
+        /// <summary>
+        /// New packages we are compiling. Used in the pin tool.
+        /// </summary>
+        [Output]
+        public ITaskItem[] PackagesToBeProduced { get; set; }
+
+        public override bool Execute()
+        {
+            return false;
+        }
+    }
+}