Page reload in Maui Hybrid Blazor app causes unhandled exception

crui3er commented 7 months ago

Is there an existing issue for this?

[X] I have searched the existing issues

Describe the bug

BlazorWebView can reload page by itself. E.g. it might happen when app is taken foreground on Android after a while. When page is reloading, WebViewManager will try to dispose previois PageContext. https://github.com/dotnet/aspnetcore/blob/main/src/Components/WebView/WebView/src/WebViewManager.cs#L221 PageContext disposing will causes disposing on components of the app. Components disposing can produce calls to JS. E.g. to dispose related js components. But Page has already a new state, old Page state is lost. E.g. if we invoke js on IJSObjectReference, it will fail with JSException with message like 'blazor.webview.js:1 JS object instance with ID 1 does not exist (has it been disposed?).'. Normally app can't handle such exception and Page (already reloaded) will notified about unhandled exception and will stop working.

This issue happens only when there is resolved scoped service that implements IAsyncDisposable which returns not completed task. In this situation JS invoke from component dispose method could be dispatched before new page context is created.

This issue is similar to https://github.com/dotnet/aspnetcore/pull/32901

Proposed solution

1) Mark PageContext as Disposed on calling PageContext .DisposeAsync https://github.com/dotnet/aspnetcore/blob/main/src/Components/WebView/WebView/src/PageContext.cs#L57 2) Mark linked WebViewJSRuntime as Disconnected. Disconnected WebViewJSRuntime should throw JSDisconnectedException on attemt to invoke JS like RemoteJSRuntime does it. See https://github.com/dotnet/aspnetcore/pull/32901 3) IpcSender. We should have special instance of IpcSender which can be linked with PageContext and do nothing if linked PageContext is disposed. This special instance on IpcSender should be passed to services in PageContext constructor (WebViewNavigationManager, WebViewJSRuntime, WebViewRenderer). This way we will protect new state of the page in webview from corruption. 4) IpcReceiver. It should also ignore received message if related PageContext is disposed. Such messages processing starts at https://github.com/dotnet/aspnetcore/blob/main/src/Components/WebView/WebView/src/IpcReceiver.cs#L49

I faced this issue in MAUI HybridBlazor project but since all related code is located in this repo, I reported the issue here.

Expected Behavior

App restarts on page reload. No unhandled exception are reported to page. No JS invoked from old PageContext are sent to new Page.

Steps To Reproduce

https://github.com/crui3er/MauiHybridBlazorReloadIssue Run app on Windows or Android (I did not test on other platfoms). Click 'Simulate page reload' button. Unhandled exception will happen.

Exceptions (if any)

No response

.NET Version

dotnet 7 dotnet 8

Anything else?

No response

mkArtakMSFT commented 7 months ago

@crui3er did you try to run this project with .NET 8 and see if you run into the same issue?

crui3er commented 7 months ago

@mkArtakMSFT yes, it's reproducible on .net 8. I'just tested it on Windows app. Also I updated repo with sample project.

ghost commented 7 months ago

To learn more about what this message means, what to expect next, and how this issue will be handled you can read our Triage Process document. We're moving this issue to the .NET 9 Planning milestone for future evaluation / consideration. Because it's not immediately obvious what is causing this behavior, we would like to keep this around to collect more feedback, which can later help us determine how to handle this. We will re-evaluate this issue, during our next planning meeting(s). If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact work.

ghost commented 6 months ago

To learn more about what this message means, what to expect next, and how this issue will be handled you can read our Triage Process document. We're moving this issue to the .NET 9 Planning milestone for future evaluation / consideration. Because it's not immediately obvious what is causing this behavior, we would like to keep this around to collect more feedback, which can later help us determine how to handle this. We will re-evaluate this issue, during our next planning meeting(s). If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact work.