Breaks a WASM .NET 7 app

[jrcpereira]

If we initialize the app with this sink, the app throws a null reference exception on the initialization of the app, causing it to fail to start.

System.NullReferenceException: Object reference not set to an instance of an object. at Microsoft.AspNetCore.Components.WebAssembly.HotReload.WebAssemblyHotReload.InitializeAsync() at Microsoft.AspNetCore.Components.WebAssembly.Hosting.WebAssemblyHost.RunAsyncCore(CancellationToken cancellationToken, WebAssemblyCultureProvider cultureProvider) at Program.<Main>$(String[] args) in C:\xxxxxxxxxxx\Program.cs:line 147

[nblumhardt]

Hi! I had a quick shot at reproducing this - looks a little like a Blazor hot reload bug, at first glance, since the app works fine with dotnet run and fails outside Serilog code in dotnet watch. The Blazor/ASP.NET Core components definitely shouldn't crash this way, even if there's something incompatible going on in the sink.

I've opened #21 to update the tooling and target versions of this project anyway. If someone has time to dig in and debug further, it'd be great to narrow this down enough to either mitigate here, or post a bug report/repro to the Blazor folks.

[cherry3]

I had the same problem after updating to .NET 7, but worked around it by removing any call to Log.Info/Error/etc from Client Program.cs

[wtorricos]

Are there any updates on this issue?

[nblumhardt]

Hi! This needs someone with Blazor knowledge (and time) to investigate. It's most likely a bug in Blazor hot reloading (production code would most likely never be expected to throw NullReferenceException) so someone raising the issue with that team and posting a link to it here would also be a useful contribution. Thanks!

[wtorricos]

Hey guys, they asked me to provide a minimal repro project.
I tried to create a new project and reproduce the issue but with no luck. Does any of you have a project that we can share with the Blazor team?
If no one does I'll try to reproduce it during the weekend, but it will speed things if someone does.

[wtorricos]

@here please take a look at the issue that I created, the guys from Blazor diagnosed it and found that it is actually a browser console issue dotnet/aspnetcore#45536
And they also left a workaround that it's working for me :)
Basically you need to do something like this;

WebAssemblyHost app = builder.Build();

Log.Logger = new LoggerConfiguration()
            .WriteTo.BrowserConsole(
                restrictedToMinimumLevel: LogEventLevel.Information,
                outputTemplate: "[{Timestamp:HH:mm:ss} {Level:u3}] {Message:lj}{NewLine}{Exception}",
                CultureInfo.InvariantCulture,
                jsRuntime: app.Services.GetRequiredService<IJSRuntime>())
            .CreateLogger();

await app.RunAsync();

The workaround is to pass the jsRuntime jsRuntime: app.Services.GetRequiredService<IJSRuntime>() parameter from the web host app.

[nblumhardt]

Awesome! Thanks for following that up!

I'm not sure about the conclusions regarding internal state - Serilog.Sinks.BrowserConsole only uses public APIs as far as I can tell (?) - but seems like the way forward will be to require an injected IJSRuntime either way 👍

Should be fixable with a new WriteTo.BrowserConsole overload, and deprecation of the old one. Would be great if anyone's able to take a look.