[Bug] [S] WebView2Loader.dll is missing in net472 app

[pmaytak]

Which Version of MSAL are you using ?
4.33

Platform
net472

What authentication flow has the issue?
Interactive WebView2

Repro 1
WebView2LoaderRepro.zip

• WebView2Library references WebView2 SDK NuGet.
• WebView2Library does specify AnyCPU PlatformTarget explicitly.
• WebView2Library is packed as a NuGet.
• WebView2App references WebView2Library as a NuGet.
• Run WebView2App for net472 target.

Repro 2

1. Use NetDesktopWinFormsWAM project.
2. Update to reference MSAL NuGet instead of source code project.
3. Build, run, do interactive request.
4. WebView2Loader error occurs.

Expected behavior
WebView2 should show up.

Actual behavior
If App targets net472, I see different behavior depending on the PlatformTarget element in the App csproj.

• None specified - BadImageFormatException
• AnyCPU - DllNotFoundException
• x86 or x64 - everything works

Additional context / logs / screenshots
Current workaround is to set PlatformTarget to either x86 or x64 in the app's project file.

Related issue in WebView2 repo:
Using WebView2 in a WPF Assembly

[bgavrilMS]

I was not able to reproduce this issue. @pmaytak - could you try to create a simple repro and open a bug on WebView2 team ? Should be sufficient to just try

string s = CoreWebView2Environment.GetAvailableBrowserVersionString();
Console.WriteLine(s);

[pmaytak]

@bgavrilMS Added zip repro above.
Bug: MicrosoftEdge/WebView2Feedback#1091

[pmaytak]

@bgavrilMS It's an issue with WebView2 SDK. Possible bug and workaround is described here. Workaround is to add <PlatformTarget>AnyCPU</PlatformTarget> to the project file. Small change, just need to test.

The explanation is pretty long but worth a read. Basically WebView2 SDK fails to build different WebView2Loader.dll version for different targets (since it's a native DLL) when the PlatformTarget element is missing. So although AnyCPU is default, we still need to add it as a workaround.

[bgavrilMS]

Nice, thanks for following this up @pmaytak !

[pmaytak]

@bgavrilMS Adding PlatformTarget element workaround doesn't work for us.

Should we exclude WebView2 here for NetFx targets?

microsoft-authentication-library-for-dotnet/src/client/Microsoft.Identity.Client/Platforms/Features/WebView2WebUi/WebView2WebUiFactory.cs

Lines 46 to 50 in c25582a

	if (_isWebView2AvailableFunc())
	{
	requestContext.Logger.Info("Using WebView2 embedded browser.");
	return new WebView2WebUi(coreUIParent, requestContext);
	}

NetDesktopWinFormsWAM still doesn't include the WebView2Loader.dll.

NetCoreWinFormsWAM does include the different WebView2Loader.dll runtimes.

Also for reference: Release notes for WebView2 SDK.

[bgavrilMS]

We should think about catching the exception and re-thrwoing a meaningful error with the workaround,

[pmaytak]

Update: Seems like the workaround doesn't work when the library is consumed as a NuGet. Left comment in the WebView2 feedback issue.

[pmaytak]

cc @bgavrilMS @mjcheetham
I may have found another workaround for this. In the client app project add <PlatformTarget>AnyCPU</PlatformTarget> and directly reference WebView2 NuGet.

[jmprieur]

@pmaytak do we want to document this in the wiki?

[pmaytak]

@jmprieur We do have it in a wiki: https://github.com/AzureAD/microsoft-authentication-library-for-dotnet/wiki/WebView2#troubleshooting. But thanks, for the reminder, I'll update it.

[bgavrilMS]

Closing as no fix. For AAD authorities, please use WAM.