Old project type GUID are used for new projects/solutions

[beppemarazzi]

Visual Studio Version

Version 17.12.2

Summary

C# projects targeting .net 9 are added to sln using "old" project type GUIDs

Steps to Reproduce

1. Create a new console app c# project OR add a class library to an existing solution
2. Open the .sln file with a text editor
3. Look at the lines starting with Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = ...

Expected Behavior

the project type GUID is expected to be Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = ... as documented here https://github.com/dotnet/project-system/blob/32c88de3973358cb38d78f78d7c7d1579fc0b4c6/docs/opening-with-new-project-system.md#project-type-guids

Actual Behavior

the project type GUID is Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = ...

User Impact

don't know if it impacts someway.
But in my real case .sln i have hundred of projects with {9A19103F-16F7-4668-BE54-9A1E7A4F7556} and now (adding new projects with the just updated visual studio) i get the (bad?) {FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}.

Does it have any impact? I don't know but just in case i'm manually "adjusting" the .sln file...

[julealgon]

This is not specific to .NET9. It apparently happens with any SDK-style project.

I've been fighting this for years now. The easiest way to fix the issue is to remove the project from the solution and re-add it. When it is added, it gets the correct GUID.

I hope the new slnx format is finished soon so that this dumb issue goes away along with the rest of the insanity that is the sln format.

[beppemarazzi]

've been fighting this for years now. The easiest way to fix the issue is to remove the project from the solution and re-add it. When it is added, it gets the correct GUID.

probably it was true for old version of visual studio. With the latest update (17.2.2) also re-adding the project to the sln uses the "bad" GUID...

For me the only workaround is to manually edit the .sln file (I've also created a before build target that issue a compilation warning in case my .sln file contains an old GUID...)

[julealgon]

With the latest update (17.2.2) also re-adding the project to the sln uses the "bad" GUID...

Oh really... I see, they managed to make it worse then 😅

Thanks for clarifying that.

[drewnoakes]

The back-and-forth between project type GUIDs for SDK-style projects should now be resolved, as part of work for SLNX. See #9509.

We now aim to use the same GUID everywhere (the legacy GUID), which should make things simpler to reason about.

[julealgon]

@drewnoakes would you mind sharing a link to where the .slnx work is being done? Ever since I first heard of it, I've been waiting for that to be released so that we can switch immediately to it on our side.

I'd like to track that if possible.

I see this item on the sdk repo. Not sure if it's the main issue though:

• slnx support in the dotnet CLI sdk#40913

[drewnoakes]

I don't know if there's a main issue. The work is being done across several products, from MSBuild to VS to CLI.