[Bug]: build /p:CreateBootstrap=true doesn't create a boostrap

[jrdodds]

Issue Description

After running ./build.sh /p:CreateBootstrap=true or build.cmd /p:CreateBootstrap=true I expected to see a artifacts\bin\bootstrap\net9.0\MSBuild\MSBuild.dll file. The artifacts\bin\bootstrap\net9.0 is not created.

Has the bootstrap been changed? A core folder with a dotnet executable is created. Is this an expected change in behavior?

In Building-Testing-and-Debugging-on-.Net-Core-MSBuild.md there is a sentence:

Now, just point dotnet ./artifacts/bin/bootstrap/<TARGET_FRAMEWORK>/MSBuild/MSBuild.dll at a project file. (Change <TARGET_FRAMEWORK> to current target framework, for example net7.0, net8.0)

Is this document out of date? Is it now ./artifacts/bin/bootstrap/core/dotnet <project_file>?

Steps to Reproduce

1. Run ./build.sh /p:CreateBootstrap=true (*nix) or build.cmd /p:CreateBootstrap=true (Windows)
2. Check the contents of ``artifacts/bin/bootstrap/`

Expected Behavior

In the past a framework folder would be created within bootstrap.

Actual Behavior

A core folder with a dotnet executable is created. Is this an expected change in behavior?

Analysis

No response

Versions & Configurations

No response

[KirillOsenkov]

I think bootstrap was primarily targeted to produce a rehostable version of the desktop MSBuild, and it seems to be working fine for that purpose.

Assuming you cloned MSBuild at C:\MSBuild the binary would be at
C:\msbuild\artifacts\bin\bootstrap\net472\MSBuild\Current\Bin\amd64\MSBuild.exe

and the root directory would be at
C:\msbuild\artifacts\bin\bootstrap\net472

You can just zip or copy that directory and it should be self-contained. The Core MSBuild is somewhat limited (e.g. it won't build WPF projects for example).

[KirillOsenkov]

To clarify: I'm not saying there isn't a bug, it may still be broken and still needs fixing. Just pointing out that the desktop version has been working fine for years for me (and I've never tried to use the Core bootstrap version)

[JanKrivanek]

The behavior for .NET was improved - to create fully functional patched version - see: https://github.com/dotnet/msbuild/blob/main/documentation/wiki/Bootstrap.md#current-implementation-for-net

@KirillOsenkov - I believe you should be now able to use Core bootstrap to build WPF as well (as soon as it's possible with fresh latest release NET sdk).

@YuliiaKovalova - the doc pointed by @jrdodds might need update.

[jrdodds]

Thanks for updating the documentation.

Quick testing shows that the artifacts/bin/bootstrap directory is now always created on a build and the CreateBootstrap property has no effect.

A search for "CreateBootstrap" across the repo turns up a few references in documentation files and build script files. Maybe these are dead files.

Regardless, the new behavior is an improvement and I'm updating my workflow.
Thanks

[JanKrivanek]

CreateBootstrap wasn't having any effect before the refactoring. But it's still good point for fixing