MSB3026 warning with nested recursive paths when using Microsoft.AspNetCore.Mvc.Testing on macOS

[KhalidSaud]

Description

Intermittent MSB3026 warnings occur when building test projects that reference Microsoft.AspNetCore.Mvc.Testing on macOS. The warning shows recursive nested paths and occurs approximately 40-50% of builds. The issue disappears completely when the package is removed.

Reproduction Steps

1. Create an ASP.NET Core 10 project on macOS
2. Add test project with Microsoft.AspNetCore.Mvc.Testing package reference
3. Run dotnet build 10-20 times consecutively
4. Warning appears intermittently (~40-50% of builds)

Expected behavior

No warnings on any build

Actual behavior

Intermittent MSB3026 warning with recursive nested paths:

Verification

Removing Microsoft.AspNetCore.Mvc.Testing package completely eliminates the warning across 20+ consecutive builds.

Environment

• OS: macOS Sequoia (Apple Silicon M3)
• Filesystem: APFS
• .NET SDK: 10.0.101
• Package: Microsoft.AspNetCore.Mvc.Testing 10.0.1

Additional Context

• Build succeeds despite warning
• Timing-dependent (race condition suspected)
• Adding <GenerateMvcApplicationPartsAssemblyAttributes>false</GenerateMvcApplicationPartsAssemblyAttributes> reduces frequency but doesn't eliminate
• Issue may be related to MSBuild path calculation on APFS filesystem