only call package restore targets on transitive projects

[brettfo]

When discovering project dependencies, we directly invoke the targets Restore, ResolveProjectReferences, and GenerateBuildDependencyFile. When MSBuild traverses through <ProjectReference> elements, it will call Build which indirectly calls the targets we care about. This extra call to Build can be slow and fill the log with unnecessary errors, although it doesn't prevent dependency discovery.

The fix is to explicitly set what targets can be called on project references to the ones we want.

[Copilot]

Pull request overview

Limits MSBuild project-reference traversal to dependency-discovery targets, avoiding unnecessary builds.

Changes:

• Configures ProjectReferenceBuildTargets.
• Adds sentinel-based regression coverage.

Show a summary per file

File	Description
SdkProjectDiscovery.cs	Restricts targets invoked on referenced projects.
DiscoveryWorkerTests.Project.cs	Verifies referenced projects are not built.

Review details

• Files reviewed: 2/2 changed files
• Comments generated: 2
• Review effort level: Medium

[Copilot]

Review details

Comments suppressed due to low confidence (1)

nuget/helpers/lib/NuGetUpdater/NuGetUpdater.Core/Discover/SdkProjectDiscovery.cs:182

• requiredTargets is chosen from the starting project's style, but this global property is inherited by every referenced project. In a mixed graph, an SDK-style root therefore asks a legacy reference to run Restore and GenerateBuildDependencyFile, even though this file's existing legacy branch documents that those targets are absent; the reverse direction restricts an SDK reference to only ResolveProjectReferences. This can produce missing-target errors or incomplete dependency data. Please select the target set in the context of each referenced project—for example, invoke a discovery target from the injected targets file that conditionally depends on the appropriate SDK/legacy targets.

                args.Add($"/p:ProjectReferenceBuildTargets=\"{string.Join(";", requiredTargets)}\"");

• Files reviewed: 2/2 changed files
• Comments generated: 0 new
• Review effort level: Medium

[mohamedelhalosy2023-stack]

Ok