Duplicate definition error in VS 2022

[Dimension4]

I'm trying to upgrade my solution to VS 2022, but if I build it I'm getting duplicate definition errors that weren't there before with VS 2019. I guess this is caused by the new .net 6 sdk?

I think a simple future proof fix would be to wrap the source code in another #if block

#if !NET
...
#endif

since NET is defined for .net 5 and later.

[i2van]

This also doesn't work in VS 2022 for netcoreapp3.1:

<ItemGroup Condition="'$(TargetFramework)'=='netcoreapp3.1'">
  <PackageReference Include="IsExternalInit" Version="1.0.1">
    <PrivateAssets>all</PrivateAssets>
    <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
  </PackageReference>
</ItemGroup>

Error CS0579: Duplicate 'DebuggerNonUserCode' attribute (58, 32)
Error CS0579: Duplicate 'ExcludeFromCodeCoverage' attribute (58, 7)
Error CS0101: The namespace 'System.Runtime.CompilerServices' already contains a definition for 'IsExternalInit' (60, 28)

[manuelroemer]

Hey, I tried to reproduce the issue, but cannot, at the moment. I created a new console app, added the package and the following code:

Console.WriteLine(new Message("Hello, World!"));

public record Message(string Mesage);

So far, everything works on my side. I successfully ran it using the netcoreapp3.1, net5.0 and net6.0 TFMs. I'm at .NET 6.0.100 and VS 17.1.0 Preview 1.0 (I only have the preview version installed right now, maybe it is that?).

Could you maybe upload a minimal example project which causes issues for you? Thanks a lot!

[i2van]

@manuelroemer Could you please create alpha/beta package with fix proposed by topic starter (see 1st line of this file) and I'll test it on this project. master can not be built using VS 2022. net6_support branch - can.

[Dimension4]

We're multi targeting .net framework 4.5.2, 4.8 and .net core 3.1. I can't do more testing at the moment because I had to uninstall VS 2022 since it also broke the builds on VS 2019.

[SWeini]

I installed the .NET 6 SDK (no VS 2022 yet) and this makes my compilation fail as well. The project is a WPF project (UseWPF=true). Works like a charm when removing the Workaround from the .targets file.

Looks like they changed something in .NET 6, see dotnet/wpf#810

[manuelroemer]

Yeah, it seems like something in the SDK/tooling changed/got broken.
Not sure how to tackle this generally, but in the meantime I am totally happy with conditionally excluding the file's content via the proposed NET toggle. That might fix some of the issues without being a problem in the future. @i2van I uploaded a new package for testing it: 1.0.2-pre1. (Branch: https://github.com/manuelroemer/IsExternalInit/tree/hotfix/v1-0-2-pre/src)

In any case, if something is wrong with the SDK, there is not much I can do at the moment. I also don't have any time for investigating where the issue is rooted. Either someone else has an idea/makes a PR for this repo or the issue gets fixed upstream by the .NET guys.

Works like a charm when removing the Workaround from the .targets file.

@SWeini That's an interesting clue, thanks a lot! Just to clarify, do you mean these definitions here? If these are an issue, we could maybe remove them altogether (I think the issue that they worked around was eventually fixed in some .NET 5 SDK update).

[i2van]

@manuelroemer It doesn't compile with new package out of the box. Looks like global.json sdk.version setting also matter. Adding file locally solves issues for both VS 2019 and 2022. Project I mentioned also uses WPF and has builds for 4.61, .NET Core 3.1, .NET 5/6

[i2van]

global.json sdk.version build with new package under VS 2022:

.NET	Result
5.0.400	OK
6.0.100	Error CS0101: The namespace 'System.Runtime.CompilerServices' already contains a definition for 'IsExternalInit'

[SWeini]

We could also remove the .targets files completely. That's how the issue seems to be solved in https://github.com/manuelroemer/Nullable
Use .NET 5 SDK and set IncludePackageReferencesDuringMarkupCompilation to true or use .NET 6 SDK and use true by default.

If you want to be backwards-compatible to SDKs before .NET 5 you might still need that workaround. I haven't tested this with all possible versions.

@SWeini That's an interesting clue, thanks a lot! Just to clarify, do you mean these definitions here? If these are an issue, we could maybe remove them altogether (I think the issue that they worked around was eventually fixed in some .NET 5 SDK update).

[manuelroemer]

We could also remove the .targets files completely. [...] If you want to be backwards-compatible to SDKs before .NET 5 you might still need that workaround.

Yes, I think that removing the workaround is the best course of action. And I think the assumption that users have an up-to-date SDK (be it .NET 5 or .NET6+) is reasonable enough. Would you like to make this change in your PR? Would be much appreciated! 🍻
(Thanks for opening your current PR, by the way!)

[i2van]

Could you upload package for testing, please?

[manuelroemer]

You mean with the change proposed by @SWeini? If so, yes, I'd upload a prerelease for testing before creating a "full" release.

[Dimension4]

@manuelroemer sorry for bumping this, but what's the plan now? I see there's a PR waiting for approval, is there anything that needs to be done?

[manuelroemer]

@manuelroemer sorry for bumping this, but what's the plan now?

No worries, bumping is more than fair here! I merged #11 and uploaded the next prerelease version for testing: https://www.nuget.org/packages/IsExternalInit/1.0.2-pre2

If that still doesn't make things work, my last remaining hope is to revert #5 and #6, but ideally we can avoid that.

[Dimension4]

@manuelroemer can confirm it works for me now 👍

[Dimension4]

Will the fix be released as a proper version 1.0.2 or do we keep the 1.0.2-pre2 tag? Just so I know when to merge back into master in our code base :)

[i2van]

Works for me.

[manuelroemer]

Will the fix be released as a proper version 1.0.2 or do we keep the 1.0.2-pre2 tag?

I'll release a 1.0.2 very soon!

[manuelroemer]

Done. Thanks to all of you for helping resolve this issue!

[Dimension4]

Thanks for providing and updating the package!

[Dimension4]

I think we've broken the old behavior now. If you try to use the new nuget package without having .net 6 sdk installed (but rather .net 5 sdk), builds break on VS 2019 with the same error

Error CS0518: Predefined type 'System.Runtime.CompilerServices.IsExternalInit' is not defined or imported

[Dimension4]

Ok it looks like it's not really broken, but the behavior changed a bit. Previously, we were able to just reference the nuget package (with .net 5) and it just worked. But now we also have to add

<IncludePackageReferencesDuringMarkupCompilation>true</IncludePackageReferencesDuringMarkupCompilation>

to make it work with .net 5. So now I can confirm it works with .net 6 as well as .net 5.

Sorry for the confusion 😅

[johanneshoehn]

@manuelroemer 1.0.1 is still the newest version on nuget.org. Was the 1.0.2 pulled, or something?

[i2van]

@manuelroemer 1.0.1 is still the newest version on nuget.org. Was the 1.0.2 pulled, or something?

https://www.nuget.org/packages/IsExternalInit/1.0.2

It was unlisted for some reason. Now it's back.

[manuelroemer]

Hey, as @i2van said, it was unlisted, probably by accident when I unlisted the prerelease versions. In any case the full 1.0.2 is back now.