Use new 'dotnet run' 9.1 options for launching projects

[karolz-ms]

Is there an existing issue for this?

• I have searched the existing issues

Is your feature request related to a problem? Please describe the problem.

In .NET 9.1 dotnet run gains two new launch options that would be useful for launching projects in the context of an Aspire app:

1. -e causes an environment variable to be applied to the application being launched, but NOT to the targets participating in the application build (unlike the old env: option).

2. --no-launch-profile-arguments allows to ignore invocation arguments in launch profiles

See dotnet/sdk#45844 for an example how these options are used in the context of dotnet watch

Describe the solution you'd like

Ideally these options would be used to launch projects when Aspire app host is launched from command line via dotnet run. The problem is they are only available in .NET 9.1 and newer. So either Aspire app host needs to somehow learn what dotnet CLI version is available and change the launch options used accordingly, or start using these new launch options only after .NET 9.1 or later becomes a required dependency for Aspire.

Additional context

@DamianEdwards FYI

[DamianEdwards]

So either Aspire app host needs to somehow learn what dotnet CLI version is available and change the launch options used accordingly

Hmm we should be able to test what version of the .NET CLI will be used before we dispatch the call to dotnet run, via a dotnet --version call or similar.

@karolz-ms just to clarify, when you say .NET 9.1, do you mean .NET SDK/CLI 9.0.200, or some other version?

[karolz-ms]

Yes, sorry, 9.0.200 series

[DamianEdwards]

Ideally we'd do feature detection instead of version detection, but I don't think we can get the output of dotnet run --help in a stable structured format today, right @baronfel?

[danmoseley]

feature detection instead of version detection

version detection is fine if features are monotonically added?

I was going to suggest return code, but I guess dotnet ignores unknown switches

[davidfowl]

This isn't happenning in 9.1

[baronfel]

Ideally we'd do feature detection instead of version detection, but I don't think we can get the output of dotnet run --help in a stable structured format today, right @baronfel?

yeah, that's right. In the extreme this is 'just' a json dump of the CLI grammar for a Command, which would be a really interesting thing. You want to check a structure and see if it contains a flag or capability?

[DamianEdwards]

You want to check a structure and see if it contains a flag or capability?

Yeah, ideally we'd check if the feature we want to invoke is present, rather than just version check.