fix: DivideByZero in FluentInputFile

[jo0ls]

🐛 Bug Report

If you set the FluentInputFile to Stream, and upload a 0 byte file then it gets a divide by zero error and never completes the upload.

💻 Repro or Code Sample

Start a new fluent web app, interactive server. Set detailed error in appsettings:

{
  "DetailedErrors": true,
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "AllowedHosts": "*"
}

Amend the home component, adding a FluentInputFile set to stream:

@page "/"

<PageTitle>Home</PageTitle>

<h1>Hello, world!</h1>

<p>@completed</p>

<FluentInputFile @ref="@myFileUploader"
DragDropZoneVisible="false"
Mode="InputFileMode.Stream"
Multiple="true"
AnchorId="MyUploadButton"
MaximumFileSize="@(100 * 1024 * 1024)"
Accept="*"
OnCompleted="@OnCompleted" />

<FluentButton Id="MyUploadButton" Appearance="Appearance.Accent">
  Upload files
</FluentButton>

@if (Files.Any())
{
  <h4>File(s) uploaded:</h4>
  <ul>
    @foreach (var file in Files)
    {
      <li>
        <b>@file.Name</b> 🔹
        @($"{Decimal.Divide(file.Size, 1024):N} KB") 🔹
        @file.ContentType 🔹
        @file.LocalFile?.FullName
        @file.ErrorMessage
      </li>
    }
  </ul>
}

@code
{
  FluentInputFile? myFileUploader = default!;
  string completed = "not completed";

  FluentInputFileEventArgs[] Files = Array.Empty<FluentInputFileEventArgs>();

  void OnCompleted(IEnumerable<FluentInputFileEventArgs> files)
  {
    completed = "completed";
    Files = files.ToArray();    
  }
}

Create a new text file, it will be 0 bytes. Attempt to upload the file.

🤔 Expected Behavior

It should upload the file and completed should fire and display the file details.

😯 Current Behavior

Nothing happens.
With detailed errors, the browser console shows a divide by zero:

blazor.web.js:1 Uncaught (in promise) Error: System.DivideByZeroException: Attempted to divide by zero.
   at :7149/System.Decimal.DecCalc.VarDecDiv(DecCalc& d1, DecCalc& d2)
   at :7149/System.Decimal.Divide(Decimal d1, Decimal d2)
   at :7149/Microsoft.FluentUI.AspNetCore.Components.FluentInputFile.UpdateProgressAsync(Int64 current, Int64 size, String title) in /_/src/Core/Components/InputFile/FluentInputFile.razor.cs:line 406
   at :7149/Microsoft.FluentUI.AspNetCore.Components.FluentInputFile.OnUploadFilesHandlerAsync(InputFileChangeEventArgs e) in /_/src/Core/Components/InputFile/FluentInputFile.razor.cs:line 323
   at Microsoft.AspNetCore.Components.ComponentBase.CallStateHasChangedOnAsyncCompletion(:7149/Task task)
    at w.endInvokeDotNetFromJS (blazor.web.js:1:3158)
    at vn._invokeClientMethod (blazor.web.js:1:65750)
    at vn._processIncomingData (blazor.web.js:1:63139)
    at connection.onreceive (blazor.web.js:1:56780)
    at i.onmessage (blazor.web.js:1:80728)

💁 Possible Solution

...

🔦 Context

It's not a big deal, but in testing people are creating empty files and reporting it.
It does upload them if set to SaveToTemporaryFolder instead of stream.

🌍 Your Environment

Win11, VS 2022, Chrome/Edge.
Net9, fluent 4.11.8

[MarvinKlein1508]

Issue is in this line.

fluentui-blazor/src/Core/Components/InputFile/FluentInputFile.razor.cs

Line 406 in 8d3f795

return UpdateProgressAsync(Convert.ToInt32(decimal.Divide(current, size) * 100), title);

Will provide a fix for this on tuesday

[MarvinKlein1508]

@vnbaaij you can close this :)

[dvoituron]

Fixed with PR #3719