Allow referencing virtual projects#13389
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jjonescz merged 2 commits intodotnet:mainfrom Mar 25, 2026
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Pull request overview
Enables ProjectReference to work with virtual (in-memory) projects when _BuildNonexistentProjectsByDefault is enabled, supporting SDK scenarios like file-based apps that synthesize projects into the ProjectRootElementCache.
Changes:
- Update
_SplitProjectReferencesByFileExistenceto treat allProjectReferenceitems as “existent” when_BuildNonexistentProjectsByDefault=true. - Add unit tests validating both the split behavior and end-to-end
ResolveProjectReferencesbehavior with in-memory projects. - Extend the spec to document
ProjectReferencebehavior and virtual project limitations (notably out-of-proc node isolation).
Reviewed changes
Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.
| File | Description |
|---|---|
| src/Tasks/Microsoft.Common.CurrentVersion.targets | Bypasses Exists() classification for project references when building nonexistent projects by default, enabling virtual references. |
| src/Build.UnitTests/BackEnd/MSBuild_Tests.cs | Adds coverage for virtual ProjectReference behavior (split + end-to-end build). |
| documentation/specs/build-nonexistent-projects-by-default.md | Documents new ProjectReference behavior and clarifies constraints for virtual projects. |
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@dotnet/msbuild for a review of this simple change that would allow us to implement |
Member
|
I really like this conceptually, because it's been pretty frustrating having to whack-a-mole support for file-based apps in other hosts. |
rainersigwald
approved these changes
Mar 25, 2026
This was referenced Mar 25, 2026
dfederm
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Apr 9, 2026
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Part of dotnet/sdk#53478.