Web Assembly doesn't work after following documentation

[davidgiga1993]

Describe the bug

When following the steps described in the documentation and running the web server using dotnet run the web app can't load due to 404 http://127.0.0.1:62860/_framework/avalonia.js

To Reproduce

Follow the guide, effectively:

dotnet workload install wasm-tools
dotnet new install avalonia.templates
mkdir BrowserTest
cd BrowserTest
dotnet new avalonia.xplat
cd BrowserTest.Browser
dotnet run

Expected behavior

The sample app should work

Avalonia version

11.1.0

OS

WebAssembly

Additional context

The template used <TargetFramework>net8.0-browser</TargetFramework>, but I also tested with net9.0-browser.

I've also noticed that the path described in the documentation under Testing AppBundle locally doesn't seem to be correct (or at least for me this doesn't match up at all, maybe it's related to the issue above?)

[maxkatz6]

Make sure you have up-to-date .NET SDK installed. I.e. latest patch releases.
There were reports of similar problems on older .NET 8 builds.

[davidgiga1993]

Yep I actually just installed .net sdk 9 (rc1) when going through the document, so should be latest

[houstonhaynes]

FYI - I'm running into a marginally related issue #17036

[hypeartist]

Same here. Latest.NET (RC1), Avalonia 11.1.0.
PS: After changing project target to net9-browser and Avalonia 11.1.3 error changed from not finding avalonia.js into:

[maxkatz6]

@davidgiga1993 you are running "net8.0" target on .NET 9 SDK. .NET Runtime team sometimes breaks compatibility between SDK versions, especially with WASM workloads.
If you want to run "net8.0", which is in stable, but using .NET 9 SDK, then you need to install another workload dotnet workload install wasm-tools-net8. As confusing it is.
We probably should add a general advice in our documentation to keep these versions in sync.

I just tested, and net8.0-browser target works well with .NET 9 SDK with wasm-tools-net8.

As for another issue when you switch to net9.0-browser, somebody of you should report it to https://github.com/dotnet/runtime.

[maxkatz6]

Just added wasm-tools-net8 note to our documentation AvaloniaUI/avalonia-docs#548

[maxkatz6]

Also, thanks for noticing that dotnet publish output path was changed. I updated documentation accordingly.

[maxkatz6]

.NET 9 issue is most likely caused by .NET runtime migrating to a newer Emnscripten version: dotnet/runtime#100334
We are blocked on SkiaSharp release, which should happen before .NET 9 stable release.

[gpatrut-matica]

I'm actually running in the same issue. I started with a clean slate. Ran all the commands in the documentation and when I went and tried running the browser project I got the missing "_framework/avalonia.js" issue. I did not change anything in the project.

.NET SDK 8.0.400
Avalonia 11.1.0
Both projects have <TargetFramework>net8.0</TargetFramework> and <TargetFramework>net8.0-browser</TargetFramework>

I tried running it with .NET 9 and the wasm-tools-net8 workload, no luck, altought I could not even build the project as I got a gigantic dump of text in the output console (none with useful information to be honest).

Edit:
I ran all the commands again now the same behaviour I experienced when running .NET 9 with wasm-tools-net8 is happening, I can no longer build the project at all. The output console got filled logs of which I'm not getting any useful information...
You can check the full log here.

[maxkatz6]

@gpatrut-matica I can't help you without project itself, and the best I can advice:

1. Recreate Browser project from the template (it was changed between 11.0 and 11.1).
2. Make sure you have latest .NET 8 SDK patches
3. Latest Avalonia itself (11.1.0 is OLD)

[houstonhaynes]

Thanks - still recovering from a hurricane hit in Asheville, NC but will give it a try as soon as other matters have settled down. 👍

[ztl8702]

I can confirm that .NET 9 SDK targeting net8.0-browser with wasm-tools-net8 workload works for me. I am using the Avalonia.XPlat template from Avalonia.Templates::11.1.0 and manually updated Avalonia version to 11.1.3.

I also noticed:

• when targeting net9.0-browser and doing a dotnet publish, avalonia.js exists at the root of wwwroot instead of at wwwroot/_framework.

  I assume this could be fixed by overriding FrameworkAssetPathResolver but I didn't go further because I also noticed some SkiaSharp exceptions. Will wait for Web Assembly doesn't work after following documentation #16989 (comment)