Hangs when loading files 12MB or larger in Linux

[pdavis68]

I'm using AvaloniaEdit in Linux. When I try to load documents over about 10MB, it simply hangs. A 10MB file will load in well under a second, but the 12MB file I have and any text file larger than that, will cause it to hang.

My code to load the documents is:

    private async Task LoadDocumentAsync(string filePath)
    {
        if (_textEditor == null || _viewModel == null)
        {
            return;
        }

        string fileContent;
        using (var stream = File.OpenRead(filePath))
        {
            // Important: Run the loading on a background thread.
            // The UI thread only handles setting the document once loaded.
            fileContent = await Task.Run(async () =>
            {
                using var reader = new StreamReader(stream);
                return await reader.ReadToEndAsync();
            });
        }

        // Create the TextDocument on the UI thread (required by AvaloniaEdit)
        var loadedDocument = new TextDocument(fileContent);

        // Update the editor document on the UI thread
        _isUpdatingText = true;
        _textEditor.Document = loadedDocument;
        _viewModel.CurrentFilePath = filePath;
        _viewModel.IsDocumentDirty = false;
        _isUpdatingText = false;
    }

I'm under the impression this is preferred to using the .Text property, which suffers from the same issue.

I have a 10MB file it loads in under a second. The next largest text file I have is 12MB and it hangs when I try to load it, or anything larger. I get not exception, I get no warnings, nothing. Just hangs.

I created a very simple test app (this code is from that) that basically has the control in the window with default settings.

Here's my .csproj with the versions I'm using:

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <OutputType>WinExe</OutputType>
    <TargetFramework>net9.0</TargetFramework>
    <Nullable>enable</Nullable>
    <ApplicationManifest>app.manifest</ApplicationManifest>
    <AvaloniaUseCompiledBindingsByDefault>true</AvaloniaUseCompiledBindingsByDefault>
  </PropertyGroup>

  <ItemGroup>
    <Folder Include="Models\" />
    <AvaloniaResource Include="Assets\**" />
  </ItemGroup>

  <ItemGroup>
    <PackageReference Include="Avalonia" Version="11.3.9" />
    <PackageReference Include="Avalonia.Desktop" Version="11.3.9" />
    <PackageReference Include="Avalonia.Themes.Fluent" Version="11.3.9" />
    <PackageReference Include="Avalonia.Fonts.Inter" Version="11.3.9" />
    <PackageReference Include="Avalonia.AvaloniaEdit" Version="11.3.0" />
    <PackageReference Include="AvaloniaEdit.TextMate" Version="11.3.0" />
    <!--Condition below is needed to remove Avalonia.Diagnostics package from build output in Release configuration.-->
    <PackageReference Include="Avalonia.Diagnostics" Version="11.3.9">
      <IncludeAssets Condition="'$(Configuration)' != 'Debug'">None</IncludeAssets>
      <PrivateAssets Condition="'$(Configuration)' != 'Debug'">All</PrivateAssets>
    </PackageReference>
    <PackageReference Include="CommunityToolkit.Mvvm" Version="8.2.1" />
  </ItemGroup>
</Project>