Re-enable ItCanTestAMultiTFMProjectWithImplicitRestore after MSBuild revert (msbuild#14349) flows in

[ViktorHofer]

Background

The MSBuild change dotnet/msbuild#14274 (passing ExcludeRestorePackageImports=true during implicit restore, behind change wave 18.10) regressed the test ItCanTestAMultiTFMProjectWithImplicitRestore with:

NuGet.targets(571,5): error MSB3202: The project file "...\TestLibrary\TestLibrary.csproj" was not found.

Root-cause analysis is in #55245. The MultiTFMXunitProject/XUnitProject test asset intentionally has a nonexistent <ProjectReference> to TestLibrary.csproj; restore is supposed to skip it gracefully. Passing ExcludeRestorePackageImports=true collapses the restore build configuration and causes the missing project to leak into a NuGet _GenerateRestoreGraphProjectEntry MSBuild call that does not set SkipNonexistentProjects, so it errors instead of skipping.

Action taken

The MSBuild change is being reverted in dotnet/msbuild#14349. To unblock codeflow in the meantime, ItCanTestAMultiTFMProjectWithImplicitRestore has been temporarily disabled.

What to do here

Re-enable ItCanTestAMultiTFMProjectWithImplicitRestore once:

1. Revert passing ExcludeRestorePackageImports during restore (#14274) msbuild#14349 (the revert) is merged, and
2. a new MSBuild build containing the revert has flowed into dotnet/sdk.

The test lives in test/dotnet.Tests/CommandTests/Test/GivenDotnetTestBuildsAndRunsTestFromCsprojForMultipleTFM.cs.

[JanProvaznik]

Second test hit by the same msbuild#14274 regression: It_builds_deps_correctly_when_projects_do_not_get_restored

The same MSBuild change (dotnet/msbuild#14274, ExcludeRestorePackageImports=true during implicit restore, change wave 18.10) also regresses Microsoft.NET.Build.Tests.GivenThatWeWantToBuildAnAppWithTransitiveNonSdkProjectRefs.It_builds_deps_correctly_when_projects_do_not_get_restored (the [DataRow("TestApp.")] case), seen on the codeflow PR #55245 (build 1507711).

Symptom

The test builds TestApp --> MainLibrary --> AuxLibrary where the two libraries are non-SDK projects deliberately marked as not restorable (the test adds a custom _IsProjectRestoreSupported target to them) and overrides their AssemblyName to TestApp.AuxLibrary / TestApp.MainLibrary. It asserts that TestApp.deps.json lists them by their AssemblyName.

With #14274 active, the assertion fails:

Expected [1] ... (actual) "AuxLibrary"  (expected) "TestApp.AuxLibrary"
Expected [2] ... (actual) "MainLibrary" (expected) "TestApp.MainLibrary"

i.e. TestApp.deps.json now lists the restore-excluded transitive references by their project name instead of their overridden AssemblyName.

Why it's the same root cause

This test exercises the exact _IsProjectRestoreSupported "projects that do not get restored" path that #14274 affects. Confirmed locally by rebuilding the SDK with MSBuild 18.10.0-1.26360.102 and toggling the change wave:

Change wave 18.10	Result
enabled (default, #14274 active)	FAIL ("TestApp." row)
MSBUILDDISABLEFEATURESFROMVERSION=18.10	PASS

Note: this one is a genuine output regression, not a malformed asset

Unlike ItCanTestAMultiTFMProjectWithImplicitRestore (whose asset has a dangling ProjectReference), this scenario is well-formed and the failure is incorrect content in the produced deps.json (wrong library names for restore-excluded projects). This is additional evidence that the msbuild#14349 revert is the right fix.

Action taken

To unblock codeflow, It_builds_deps_correctly_when_projects_do_not_get_restored has been temporarily disabled the same way ([Ignore("https://github.com/dotnet/sdk/issues/55263")]), in test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAnAppWithTransitiveNonSdkProjectRefs.cs.

What to do here (updated)

Re-enable both tests once dotnet/msbuild#14349 (the revert) is merged and a new MSBuild build containing it has flowed into dotnet/sdk:

• ItCanTestAMultiTFMProjectWithImplicitRestore — test/dotnet.Tests/CommandTests/Test/GivenDotnetTestBuildsAndRunsTestFromCsprojForMultipleTFM.cs
• It_builds_deps_correctly_when_projects_do_not_get_restored — test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAnAppWithTransitiveNonSdkProjectRefs.cs