Windows: Duplicate 'global::System.Runtime.Versioning.TargetFrameworkAttribute' attribute

[MacKenzieHnC]

Bug report

Summary

EDIT: Okay, this is the root issue. Still working on how to solve it, but it seems to only affect C#

Reproducible sample code

A different issue pops up in a minimal repro, but I think they have the same root cause.

Payload contains two or more files with the same destination path 'Microsoft.UI.Xaml.Markup.winmd', but they have different content

Repro: https://github.com/MacKenzieHnC/DocumentPickerBug

I'm pretty sure the error comes from this change. Look at the additions to windows/DocumentPickerBug.sln.

I'm not sure that that's the error, but it seems most likely to me right now.

Steps to reproduce

1. New project using current RNW
2. Install this module
3. Build fails

Environment info

npx react-native info output:

System:
    OS: Windows 10 10.0.19045
    CPU: (12) x64 Intel(R) Core(TM) i7-8700 CPU @ 3.20GHz
    Memory: 7.00 GB / 15.93 GB
  Binaries:
    Node: 18.12.1 - C:\Program Files\nodejs\node.EXE
    Yarn: 1.22.19 - C:\Program Files (x86)\Yarn\bin\yarn.CMD
    npm: 9.2.0 - C:\Program Files\nodejs\npm.CMD
    Watchman: Not Found
  SDKs:
    Android SDK:
      API Levels: 29, 30, 31, 33
      Build Tools: 29.0.2, 30.0.2, 30.0.3, 31.0.0, 33.0.0, 33.0.1
      System Images: android-28 | Google Play Intel x86 Atom, android-30 | Google APIs Intel x86 Atom
      Android NDK: 22.1.7171670
    Windows SDK:
      AllowDevelopmentWithoutDevLicense: Enabled
      AllowAllTrustedApps: Enabled
      Versions: 10.0.17763.0, 10.0.18362.0, 10.0.19041.0, 10.0.22000.0, 10.0.22621.0
  IDEs:
    Android Studio: AI-221.6008.13.2211.9514443
    Visual Studio: 17.5.33424.131 (Visual Studio Community 2022)
  Languages:
    Java: 11.0.18 - C:\Program Files\Microsoft\jdk-11.0.18.10-hotspot\bin\javac.EXE
  npmPackages:
    @react-native-community/cli: Not Found
    react: 18.2.0 => 18.2.0
    react-native: 0.71.0 => 0.71.0
    react-native-windows: 0.71.1 => 0.71.1
  npmGlobalPackages:
    *react-native*: Not Found

library version: 8.1.3

iOS / Android version: N/A

[MacKenzieHnC]

For reasons I cannot comprehend, changing the target platform version in ReactNativeDocumentPicker.csproj from

<TargetPlatformVersion Condition=" '$(TargetPlatformVersion)' == ''">10.0.18362.0</TargetPlatformVersion>

to

<TargetPlatformVersion Condition=" '$(TargetPlatformVersion)' == ''">10.0.19041.0</TargetPlatformVersion>

fixes the minimal repro,

EDIT: but not the original project, so I guess they aren't the same error after all. I'll try and find what other module is playing badly with this.

[MacKenzieHnC]

I still don't know what the core issue is, but there's a ton of duplicate errors coming from the included Microsoft.React.Managed projects

EDIT: And I've now managed to reproduce the bugs on a new blank module, so it's not unique to this module.

[MacKenzieHnC]

Managed to get a workaround, but I don't feel good about it. I just followed every error to the file it listed and commented out the offending code. Commenting auto-generated code does not feel like a valid solution, but we're kind of at Microsoft's whims for the time being.

I can close this if you want, but, while the bug doesn't originate here, it certainly affects this repo.