Build WindowsCommunityToolkit fails with 'An item with the same key...'

[PhilPJL]

My copy of the repo is at 20/05/2022 main branch.
When I try to build (VS 2022 17.2.1) I get

Any ideas?

[RossCoeH]

We cannot see your code, but I get similar from Mvvm source generators when I incorrectly use upper case names for ObservableProperty variables. The message means what it says. The same variable is being defined in different parts of the partial class files. Ignore my comment if not using mvvm source generators, but do refine your question.

[PhilPJL]

All I did was clone the repo, open it and hit build. If I ignore the message the build then completes apparently successfully. However attempting to run the SampleApp then has the same issue and the app doesn't start.

[michael-hawker]

We haven't seen this issue before. Could be a missing dependency?

If you just try and rebuild the sample app vs. running it and look at the output window does it build successfully?

Does everything build if you run the build/build.bat script from a VS command prompt?

[PhilPJL]

build.bat completed successfully - but didn't build the samples.

Building the samples in VS gave me the same error, then apparently succeeded, but produced no output in the bin/x86/.. folder.
There were some warnings like:

CSC : warning CS8785: Generator 'IMessengerRegisterAllGenerator' failed to generate source. It will not contribute to the output and compilation errors may occur as a result. Exception was of type 'ArgumentException' with message 'The hintName 'UITests.App.MainTestHost.cs' of the added source file must be unique within a generator.

[michael-hawker]

If you change the architecture off of Any CPU do you hit the same result?

If you search for the "item with the same key" in the Output Window in VS, is there more info there or other errors?

[PhilPJL]

Yes same result with x86.
The warning isn't in the output window.

I do get these warnings:

11>------ Build started: Project: Microsoft.Toolkit.Win32.WpfCore.SampleApp.PackagingProject, Configuration: Debug Any CPU ------
11>C:\Users\passp\source\repos\WindowsCommunityToolkit\Microsoft.Toolkit.Win32.WpfCore.SampleApp\Microsoft.Toolkit.Win32.WpfCore.SampleApp.csproj : error MSB4057: The target "GetTargetPathWithTargetPlatformMoniker" does not exist in the project.
11>Done building project "Microsoft.Toolkit.Win32.WpfCore.SampleApp.csproj" -- FAILED.
11>C:\Users\passp\source\repos\WindowsCommunityToolkit\Microsoft.Toolkit.Win32.WpfCore.SampleApp\Microsoft.Toolkit.Win32.WpfCore.SampleApp.csproj : error MSB4057: The target "GetTargetPath" does not exist in the project.
11>Done building project "Microsoft.Toolkit.Win32.WpfCore.SampleApp.csproj" -- FAILED.
9> UnitTests.Notifications.UWP -> C:\Users\passp\source\repos\WindowsCommunityToolkit\UnitTests\UnitTests.Notifications.UWP\bin\x86\Debug\UnitTests.Notifications.UWP.exe
5>CSC : warning CS8785: Generator 'IMessengerRegisterAllGenerator' failed to generate source. It will not contribute to the output and compilation errors may occur as a result. Exception was of type 'ArgumentException' with message 'The hintName 'UITests.App.MainTestHost.cs' of the added source file must be unique within a generator.
5>CSC : warning CS8785: Generator 'IMessengerRegisterAllGenerator' failed to generate source. It will not contribute to the output and compilation errors may occur as a result. Exception was of type 'ArgumentException' with message 'The hintName 'UITests.App.MainTestHost.cs' of the added source file must be unique within a generator.
5>C:\Users\passp\source\repos\WindowsCommunityToolkit\UITests\UITests.App\Microsoft.Toolkit.Mvvm.SourceGenerators\Microsoft.Toolkit.Mvvm.SourceGenerators.NullabilityAttributesGenerator\System.Diagnostics.CodeAnalysis.NotNullIfNotNullAttribute.cs(20,67,20,80): warning SA1101: Prefix local calls with this
5>C:\Users\passp\source\repos\WindowsCommunityToolkit\UITests\UITests.App\Microsoft.Toolkit.Mvvm.SourceGenerators\Microsoft.Toolkit.Mvvm.SourceGenerators.NullabilityAttributesGenerator\System.Diagnostics.CodeAnalysis.NotNullAttribute.cs(1,1,1,1): warning SA1633: The file header XML is invalid.
5>C:\Users\passp\source\repos\WindowsCommunityToolkit\UITests\UITests.App\Microsoft.Toolkit.Mvvm.SourceGenerators\Microsoft.Toolkit.Mvvm.SourceGenerators.NullabilityAttributesGenerator\System.Diagnostics.CodeAnalysis.NotNullAttribute.cs(15,27,15,43): warning SA1649: File name should match first type name.
5>C:\Users\passp\source\repos\WindowsCommunityToolkit\UITests\UITests.App\Microsoft.Toolkit.Mvvm.SourceGenerators\Microsoft.Toolkit.Mvvm.SourceGenerators.NullabilityAttributesGenerator\System.Diagnostics.CodeAnalysis.NotNullIfNotNullAttribute.cs(1,1,1,1): warning SA1633: The file header XML is invalid.
5>C:\Users\passp\source\repos\WindowsCommunityToolkit\UITests\UITests.App\Microsoft.Toolkit.Mvvm.SourceGenerators\Microsoft.Toolkit.Mvvm.SourceGenerators.NullabilityAttributesGenerator\System.Diagnostics.CodeAnalysis.NotNullIfNotNullAttribute.cs(14,27,14,52): warning SA1649: File name should match first type name.
5> UITests.App -> C:\Users\passp\source\repos\WindowsCommunityToolkit\UITests\UITests.App\bin\x86\Debug\UITests.App.exe
10>C:\Users\passp\source\repos\WindowsCommunityToolkit\Microsoft.Toolkit.Uwp.SampleApp\Pages\SampleController.xaml(112,18): XamlCompiler warning WMC1500: 'DropShadowPanel' is deprecated: DropShadowPanel will be removed in a future release, please use the AttachedDropShadow or AttachedCardShadow implementations instead.
5> UITests.App -> C:\Users\passp\source\repos\WindowsCommunityToolkit\UITests\UITests.App\AppPackages\UITests.App_1.0.0.0_x86_Debug_Test\UITests.App_1.0.0.0_x86_Debug.msix
10>C:\Users\passp\source\repos\WindowsCommunityToolkit\Microsoft.Toolkit.Uwp.SampleApp\SamplePages\RadialGradientBrush\RadialGradientBrushPage.xaml(13,18): XamlCompiler warning WMC1500: 'RadialGradientBrush' is deprecated: Please migrate to the RadialGradientBrush control from WinUI, this control will be removed in a future release. https://aka.ms/winui
10>C:\Users\passp\source\repos\WindowsCommunityToolkit\Microsoft.Toolkit.Uwp.SampleApp\SamplePages\RadialProgressBar\RadialProgressBarPage.xaml(10,10): XamlCompiler warning WMC1500: 'RadialProgressBar' is deprecated: The platform ProgressRing now supports determinate mode and is part of WinUI 2.5, please upgrade to use that control: https://docs.microsoft.com/windows/apps/winui/winui2/release-notes/winui-2.5#determinate-progressring

I'll try building on a different machine. It's probably my setup. May take me a day or two.

[michael-hawker]

It's weird to see anything related to the source generators in your output though. Like the path UITests\UITests.App\Microsoft.Toolkit.Mvvm.SourceGenerators shouldn't be a thing. Have you done a git clean -xdf as well? Though you said it was a fresh clone.

There can also be issues with max filepath, so you could also try cloning close to your hard drive's root directory (which may be what the get target path errors are about).

[PhilPJL]

I created a new Azure VS2022 Community virtual machine on Windows 11. Updated to 17.2.2.
Added .NET 4.6.1 targeting pack, because some project needs it.
Removed Xaml island unit test projects because they insist on building even though not selected in the configuration manager (and they fail to build).
Run build which completes successfully, but there's no output for the sampleapp, and the sampleapp won't run.

I still get these warnings

30>------ Rebuild All started: Project: UITests.App, Configuration: Debug x86 ------
30>CSC : warning CS8785: Generator 'IMessengerRegisterAllGenerator' failed to generate source. It will not contribute to the output and compilation errors may occur as a result. Exception was of type 'ArgumentException' with message 'The hintName 'UITests.App.MainTestHost.cs' of the added source file must be unique within a generator.
30>CSC : warning CS8785: Generator 'IMessengerRegisterAllGenerator' failed to generate source. It will not contribute to the output and compilation errors may occur as a result. Exception was of type 'ArgumentException' with message 'The hintName 'UITests.App.MainTestHost.cs' of the added source file must be unique within a generator.
30>C:\Users<user>\source\repos\WindowsCommunityToolkit\UITests\UITests.App\Microsoft.Toolkit.Mvvm.SourceGenerators\Microsoft.Toolkit.Mvvm.SourceGenerators.NullabilityAttributesGenerator\System.Diagnostics.CodeAnalysis.NotNullAttribute.cs(1,1,1,1): warning SA1633: The file header XML is invalid.
30>C:\Users<user>\source\repos\WindowsCommunityToolkit\UITests\UITests.App\Microsoft.Toolkit.Mvvm.SourceGenerators\Microsoft.Toolkit.Mvvm.SourceGenerators.NullabilityAttributesGenerator\System.Diagnostics.CodeAnalysis.NotNullAttribute.cs(15,27,15,43): warning SA1649: File name should match first type name.
30>C:\Users<user>\source\repos\WindowsCommunityToolkit\UITests\UITests.App\Microsoft.Toolkit.Mvvm.SourceGenerators\Microsoft.Toolkit.Mvvm.SourceGenerators.NullabilityAttributesGenerator\System.Diagnostics.CodeAnalysis.NotNullIfNotNullAttribute.cs(1,1,1,1): warning SA1633: The file header XML is invalid.
30>C:\Users<user>\source\repos\WindowsCommunityToolkit\UITests\UITests.App\Microsoft.Toolkit.Mvvm.SourceGenerators\Microsoft.Toolkit.Mvvm.SourceGenerators.NullabilityAttributesGenerator\System.Diagnostics.CodeAnalysis.NotNullIfNotNullAttribute.cs(14,27,14,52): warning SA1649: File name should match first type name.
30>C:\Users<user>\source\repos\WindowsCommunityToolkit\UITests\UITests.App\Microsoft.Toolkit.Mvvm.SourceGenerators\Microsoft.Toolkit.Mvvm.SourceGenerators.NullabilityAttributesGenerator\System.Diagnostics.CodeAnalysis.NotNullIfNotNullAttribute.cs(20,67,20,80): warning SA1101: Prefix local calls with this
30> UITests.App -> C:\Users<user>\source\repos\WindowsCommunityToolkit\UITests\UITests.App\bin\x86\Debug\UITests.App.exe
30> UITests.App -> C:\Users<user>\source\repos\WindowsCommunityToolkit\UITests\UITests.App\AppPackages\UITests.App_1.0.0.0_x86_Debug_Test\UITests.App_1.0.0.0_x86_Debug.msix
30> UITests.App -> obj\x86\Debug\Symbols\UITests.App_1.0.0.0_x86_Debug.appxsym

So, the SampleApp wasn't being created because it wasn't selected in the configuration manager.
Selecting it and trying to build produces:

8>C:\Users<user>\source\repos\WindowsCommunityToolkit\Microsoft.Toolkit.Uwp.SampleApp\Microsoft.Toolkit.Uwp.SampleApp.csproj : XamlCompiler error WMC1006: Cannot resolve Assembly or Windows Metadata file 'C:\Users<user>\source\repos\WindowsCommunityToolkit\Microsoft.Toolkit.Uwp.Samples.BackgroundTasks\bin\Debug\Microsoft.Toolkit.Uwp.Samples.BackgroundTasks.winmd'
8>CSC : error CS0006: Metadata file 'C:\Users<user>\source\repos\WindowsCommunityToolkit\Microsoft.Toolkit.Uwp.Samples.BackgroundTasks\bin\Debug\Microsoft.Toolkit.Uwp.Samples.BackgroundTasks.winmd' could not be found
8>C:\Program Files (x86)\Windows Kits\10\bin\10.0.19041.0\XamlCompiler\Microsoft.Windows.UI.Xaml.Common.targets(486,5): error MSB4181: The "CompileXaml" task returned false but did not log an error.
6>UnitTests.Notifications.NetCore -> C:\Users<user>\source\repos\WindowsCommunityToolkit\UnitTests\UnitTests.Notifications.NetCore\bin\Debug\netcoreapp3.1\UnitTests.Notifications.NetCore.dll
========== Build: 3 succeeded, 1 failed, 27 up-to-date, 4 skipped ==========

[michael-hawker]

Are you building the Any CPU configuration? Have you tried x64? It looks like the BackgroundTasks project isn't building, it's checkbox may be missing as well? You're trying to build the Microsoft.Toolkit.Uwp.SampleApp correct? (And you have the Windows SDK installed on the VM as well?)

@Sergio0694 no idea why we're getting all those source generator warnings? Looks like the test app is referencing the MVVM package for some reason? Of course, those don't have anything to do with this issue.

This I think is a duplicate of #4161, which I thought we had resolved. Seems it's fixed in a larger PR by @Nirmal4G - would be great to get that isolated as a separate easy fix.