[WASM][.NET7] Strange error in browser console

[DierkDroth]

I see this error in browser console
uno-bootstrap.js:261 Uncaught (in promise) .NET runtime initialization failed (TypeError: Cannot read properties of null (reading 'querySelector'))
.. when trying to start my app which I migrated from .NET6 to .NET7.

This prevents the app from starting

Any idea what's going on?

[jeromelaban]

Which version of the uno bootstrapper are you running?

[jeromelaban]

I was on mobile, I missed the version. Then I do not know what causes this. If it works with no index.html override, try redoing your changes one by one.

[DierkDroth]

@jeromelaban above I tried to explain that I was testing both ways:

• standard index.html (no overwrite)
• customized index.html
  Please see screenshots above for the different errors in both cases

Either way: I can't start my app.

[jeromelaban]

Thanks. If you can provide a repro, we'll be able to troubleshoot.

[DierkDroth]

@jeromelaban please understand this is my 'real world' app/project which I'm trying to migrate to .NET7. Obviously I simply can't upload that project as a repo.

On the other hand I would expect that I would not run into any such trouble starting with a fresh, blank sample project - apart from the fact that I haven't been able to create a fresh .NET7 project as per my other inquiry. Hence, this is not an option for a repo neither.

So what to do?

[jeromelaban]

We can only work on repro cases unfortunately, and we cannot guess what's breaking by using screenshots only.

[DierkDroth]

FYI for anyone who's running into that issue.

I was able to resolve by:

• applying launchSettings.json from a .NET7 blank project: the one I had with .NET6 did no longer work
• applying standard index.html + re-applying customizations as needed. The custom index.html I had with .NET6 no longer worked.