Blazor ErrorBoundary child component exception

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

I have one custom ErrorBoundary component that I’m placing in MainLayout. If there is an error in any child component, it goes into an endless loop within the parent component. Thank you in advance for your help. I’m also including the link to the solution:

https://github.com/accacc/EndlessLoop

Expected Behavior

no recursive loop

Steps To Reproduce

    @inherits ErrorBoundary
    @inject ISnackbar Snackbar
    @if (CurrentException is null)
    {
        @ChildContent
    }
    else if (ErrorContent is not null)
    {
        @ErrorContent(CurrentException)
    }
    else
    {
        @ChildContent
    
        @foreach (var exception in receivedExceptions)
        {
            Snackbar.Add(@exception.Message, Severity.Error);
            @exception.Message
        }  
    
    }
    
    @code {
        List<Exception> receivedExceptions = new();
    
        protected override Task OnErrorAsync(Exception exception)
        {
            receivedExceptions.Add(exception);
            return  base.OnErrorAsync(exception);
        }   
        
    }

Parent Component

@page "/"

@inject ISnackbar Snackbar
@using System.Net;


<PageTitle>Index</PageTitle>

<h1>Hello, world!</h1>

@error - @ex

Welcome to your new app.

<SurveyPrompt Title="How is Blazor working for you?" />

<MyComp></MyComp>


@code{
    public int error;
    public string ex;

    protected override Task OnInitializedAsync()
    {
        //Snackbar.Add("OK", Severity.Error);
        return base.OnInitializedAsync();
    }
}

Child component

<h3>MyComp</h3>

@error

@code {
    public int error;

    protected async override Task OnInitializedAsync()
    {
        await Task.Delay(5);

        error++;
        throw new Exception("aaa");

    }
}

Exceptions (if any)

no

.NET Version

6.0

Anything else?

No response

[SteveSandersonMS]

You’re calling Recover from inside the rendering logic of your error boundary. So each time there’s an exception, it will instantly switch back into a non-error state, and hence re-render its original child content, which will then throw again. That’s why there’s an infinite loop. Also you’re only waiting for 5ms before throwing, so this is throwing 200 times per second.

To avoid the infinite loop, don’t call Recover from your rendering logic. If you’re going to call Recover at all, you should only do so:

• When the user performs some gesture like clicking a button to say they want to retry
• Or perhaps if something else has changed in your system to give you a reason to believe the error isn’t going to happen again

[SteveSandersonMS]

Not if your goal is to have “on error continue next”-style semantics, no.

If your goal is to perform logging, consider implementing a custom logger provider (docs: https://learn.microsoft.com/en-us/aspnet/core/blazor/fundamentals/logging?view=aspnetcore-7.0#custom-logger-provider-blazor-webassembly)