Dotnet add project to solution command just fails starting with newest 9.x SDK

[xafero]

Describe the bug

I very often use the add-command to add newly created projects to my solution. Now it just simply fails without any sense or reason. It would seem that it tries to take my path to a project as the name of the item-to-be-added? Crazy. Because in the past versions (I have to downgrade to .NET 8 for now), it of course reads the referenced project file and just works.

To Reproduce

c:\Code\some>dotnet sln add ..\common\Data.Forms
Names cannot:

• contain any of the following characters: / ? : \ * " < > |
• contain control characters
• be system reserved names, including 'CON', 'AUX', 'PRN', 'COM1' or 'LPT2'
• be '.' or '..' (Parameter 'name')

c:\Code\some>dotnet --list-sdks
1.1.0 [C:\Program Files\dotnet\sdk]
3.1.426 [C:\Program Files\dotnet\sdk]
5.0.408 [C:\Program Files\dotnet\sdk]
6.0.136 [C:\Program Files\dotnet\sdk]
6.0.321 [C:\Program Files\dotnet\sdk]
9.0.200 [C:\Program Files\dotnet\sdk]

Until .NET 8.0.406 at least, the same command actually works and adds my project to the solution.

Why, on Earth, did this awful change happen? Please fix this. I'm mostly working in command-line.

[baronfel]

@edvilme is this another example of the relative path bug that you've fixed already? If so, the fix will be in next month's release.

[edvilme]

Yes, when the project path gets resolved, it attempts to create solution folder ".." which as the error suggests is not valid. A fix for this has already been merged for 9.0.2xx. See #46456

[baronfel]

Thanks for confirming! I'll close this as it's been fixed by #46456, then. @xafero you should be good to go next month when 9.0.201 releases.

[sahin52]

The same error happens when you try to add a project to solution with full name:
dotnet sln .\my.sln add C:\tmp\my.csproj

[edvilme]

The same error happens when you try to add a project to solution with full name:
dotnet sln .\my.sln add C:\tmp\my.csproj

Yes, this is due to the relative project location being outside of the solution working directory. Hence it eventually gets resolved to ../../tmp/my.csproj

The same error happens when you try to add a project to solution with full name:
dotnet sln .\my.sln add C:\tmp\my.csproj

Yes, this is due to the relative project location being outside of the solution working directory. Hence it eventually gets resolved to ../../tmp/my.csproj

yes, I've also noticed that this error does show up when this specific criteria is meet, however, if the reference project IS INDEED in the same parent folder, the command works with no issue