Opt-in .sln parsing with Microsoft.VisualStudio.SolutionPersistence

[surayya-MS]

Context

Require opt-in (instead of -out) to .sln parsing with the new parser from Microsoft.VisualStudio.SolutionPersistence.
this is #11487 targeted 17.14. We decided to revert the change in 17.13

Changes Made

1. Reverted Revert ".slnx support - use the new parser for .sln and .slnx (#10836)"
2. Added MSBUILD_SLN_PARSING_SOLUTIONPERSISTENCE_OPTIN as an opt-in environment variable instead of requiring changewave opt-out to return to the MSBuild-internal solution parser.
3. Fixed tests

Testing

Changed tests to opt-in to .sln parsing with the new parser from Microsoft.VisualStudio.SolutionPersistence.

Notes

[surayya-MS]

the changes are exactly same as in https://github.com/dotnet/msbuild/pull/11487/files#diff-047e3c8fd3315f9a08db8ca4fabd30b15f324080bebc140fe1652e5d8f8af4d1
except for the version bump. You can chek this for easier review

[akoeplinger]

Can we also update the SolutionPersistence package to the latest version https://github.com/microsoft/vs-solutionpersistence/releases/tag/v1.0.52 ?

msbuild/eng/Versions.props

Line 43 in d047377

<MicrosoftVisualStudioSolutionPersistenceVersion>1.0.28</MicrosoftVisualStudioSolutionPersistenceVersion>

It has a fix for an issue that broke a test in the sdk repo.

[surayya-MS]

Can we also update the SolutionPersistence package to the latest version https://github.com/microsoft/vs-solutionpersistence/releases/tag/v1.0.52 ?

msbuild/eng/Versions.props

Line 43 in d047377

<MicrosoftVisualStudioSolutionPersistenceVersion>1.0.28</MicrosoftVisualStudioSolutionPersistenceVersion>

It has a fix for an issue that broke a test in the sdk repo.

Yes, we'll update in the next PR

[kasperk81]

dotnet/sdk#47328 is upgrading to 1.0.52 for 9.0.2 which has fixes for the issues reported in msbuild issue tracker (source-build-externals is also updated)

[maridematte]

/backport to vs17.14

[github-actions]

Started backporting to vs17.14: https://github.com/dotnet/msbuild/actions/runs/13788533134

[github-actions]

@maridematte an error occurred while backporting to "vs17.14", please check the run log for details!

Error: @maridematte is not a repo collaborator, backporting is not allowed. If you're a collaborator please make sure your dotnet team membership visibility is set to Public on https://github.com/orgs/dotnet/people?query=maridematte

[maridematte]

/backport to vs17.14

[github-actions]

Started backporting to vs17.14: https://github.com/dotnet/msbuild/actions/runs/13788605583