Consume requested targets when constructing the graph

Author: dfederm

Directory.Packages.props

@@ -3,7 +3,7 @@
   <PropertyGroup>
     <ArtifactsPackageVersion>19.232.34508-buildid25403274</ArtifactsPackageVersion>
     <BuildXLPackageVersion>0.1.0-20240121.1</BuildXLPackageVersion>
-    <MSBuildPackageVersion>17.8.3</MSBuildPackageVersion>
+    <MSBuildPackageVersion>17.9.5</MSBuildPackageVersion>
   </PropertyGroup>
   <ItemGroup>
     <PackageVersion Include="coverlet.collector" Version="3.1.2" />

src/Common/MSBuildCachePluginBase.cs

@@ -273,8 +273,8 @@ private async Task BeginBuildInnerAsync(CacheContext context, PluginLoggerBase l
         Parser parser = new(logger, _repoRoot);
         IReadOnlyDictionary<ProjectGraphNode, ParserInfo> parserInfoForNodes = parser.Parse(graph);
 
-        // TODO: MSBuild should give this to us via CacheContext
-        var entryProjectTargets = Array.Empty<string>();
+        // In practice, the underlying type of the IReadOnlyCollection is a ICollection<string> so attempt to cast first. We're not mutating the collection so still abiding by the readonly-ness.
+        ICollection<string> entryProjectTargets = context.RequestedTargets as ICollection<string> ?? new List<string>(context.RequestedTargets);
         IReadOnlyDictionary<ProjectGraphNode, ImmutableList<string>> targetListPerNode = graph.GetTargetLists(entryProjectTargets);
 
         Dictionary<NodeDescriptor, NodeContext> nodeContexts = new(parserInfoForNodes.Count);