add dotnet new sln --format slnx

[kasperk81]

dotnet new sln --help
Solution File
Author: Microsoft
Description: Create an empty solution containing no projects

Usage:
  dotnet new sln [options] [template options]
  dotnet new solution [options] [template options]

Options:
  -n, --name <name>      The name for the output being created. If no name is specified, the name of the output directory is used.
  -o, --output <output>  Location to place the generated output.
  --dry-run              Displays a summary of what would happen if the given command line were run if it would result in a template creation.
  --force                Forces content to be generated even if it would change existing files.
  --no-update-check      Disables checking for the template package updates when instantiating a template.
  --project <project>    The project that should be used for context evaluation.

Template options:
  -f, --format <sln|slnx>  Choose the format for the solution file: traditional (.sln) or XML-based (.slnx).
                           Type: choice
                             sln   Traditional solution file
                             slnx  XML-based solution file
                           Default: sln

default (without --format) is .sln.

Contributes to #40913

[kasperk81]

@baronfel ptal. i don't know why the ci is not starting here. i tried closing reopening and pushing changes but no luck

[baronfel]

@kasperk81 my best guess is that resources are slammed right now preparing for .NET 9 GA? I'll kick them and see if that helps.

[baronfel]

/azp run dotnet-sdk-public-ci,sdk-source-build, sdk-unified-build

[baronfel]

The content here seems fine - though without dotnet sln add and dotnet sln remove users won't be able to really do anything useful with the slnx yet. That's fine, I just wanted to call it out for now.

Thank you for taking an interest in this @kasperk81!

[kasperk81]

Thanks @baronfel! This PR (dotnet new sln -f slnx, adding a new argument to an existing command) and the related PR #44419 (dotnet sln migrate, introducing a new command) are two of the three PRs required to complete this feature. The upcoming PR will focus on adding slnx support to dotnet sln {add, remove, list} and may also replace SlnFile.cs with vs-solutionpersistence to handle both traditional and XML formats for loading, modifying, and saving the solution model, given that vs-solutionpersistence supports both with unified API. Once all three PRs are merged, we can backport them to the 9.0.200 branch.

[baronfel]

/azp run

[kasperk81]

saw same issue in #44481. it seems to be randomly filtering out some PRs and running for others

[just-ero]

Will slnx become the default at some point?

[baronfel]

Yes, but that will require coordination with the VS solution team around when they want to make the format 'stable' and default to it in VS. Having that decision require just a very small boolean default value change in the template here is a smart move by @kasperk81 to make the cost of updating the SDK to match VS very light.

[kasperk81]

@surayya-MS, @rainersigwald, do you and your team have any suggestions (drawing on your experience with MSBuild) for implementing the dotnet sln {add, remove, list} commands? I’m thinking of structuring this work in two PRs:

• First PR: Remove src/Cli/Microsoft.DotNet.Cli.Sln.Internal and replace it with vs-solutionpersistence, adjusting all relevant extensions and usage. This part could be tricky because AddFolder and certain solution configurations don’t map 1:1, so I’d love to know if you encountered similar challenges during the MSBuild port and how you approached them.
• Second PR: Introduce .slnx support for these commands.

Would you or someone from your team be interested in helping with the initial replacement or providing input? Any insights from the MSBuild transition would be especially helpful. Thank you! 😊

[baronfel]

saw same issue in #44481. it seems to be randomly filtering out some PRs and running for others

There's an infrastructure issue in AzDo that's being worked on right now. Will bump this as I know more.

[baronfel]

This LGTM, but I'm waiting for feedback from the VS Solution team about what they would like to call the two options for sln/slnx formats.

[baronfel]

Ok I have feedback from the VS team on their desired terminology for the sln/slnx choice help text.

@kasperk81 please use the phrases "Solution file" and "XML Solution file" instead of "Traditional solution file" and "XML-based solution file". Other than that change this is good to go!

[baronfel]

Thanks for this @kasperk81!

[baronfel]

/backport to release/9.0.2xx

[github-actions]

Started backporting to release/9.0.2xx: https://github.com/dotnet/sdk/actions/runs/11602176374