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.