feat: Notify JS-layer when webview crashed

Feature Request

It would be great if the JS-layer (Capacitor app) could know that the underlying web view crashed and subsequently restarted. Right now there is nothing to discern these from a regular app startup and users won’t be aware that data was lost.

More concretely, an issue that occur frequently is that we take a photograph via an <input capture> element and do on-the-fly resize using JS and canvas, and the web view crashes, causing the page to reload. But for the user this isn’t obvious, it’s just a short flash when the web view reloads, and they don’t know that the photograph failed and they’ve just lost data.

If we could listen to these events we could show a warning to the user.

This is the code on iOS today:

https://github.com/ionic-team/capacitor/blob/0a25cce21f935c0d18cdeb9b0e04a9b6145f2072/ios/Capacitor/Capacitor/CAPBridgeViewController.swift#L279-L281

Platform Support Requested

• Android
• iOS

Describe Preferred Solution

There are multiple solutions, but one could be a listener similar to appRestoredResult , that would let us know that the app restored after a crash.

We’d then have the ability to show a warning to the user.

Additional Context

This related issue about the web view crashing when taking photos: https://github.com/ionic-team/capacitor/issues/2265

[diachedelic]

We have found the iOS WebView to be very sensitive to memory usage. It crashes quite often on startup, possibly due to this bug: https://bugs.webkit.org/show_bug.cgi?id=212790. If you have any memory leaks in the WebView, it will eventually be terminated. WebKit unfortunately has some nasty memory leaks associated with the <video> and <canvas> elements.

In general, an automatic reload is necessary in production. But I would prefer a crash in development. And ideally, we should be able to override the default behaviour, so we can maintain the integrity of the app.

[diachedelic]

Would it be so crazy to crash the app if webViewWebContentProcessDidTerminate was called? I think I would prefer the app to quit immediately and obviously, rather than data disappearing silently. Perhaps it could be a configuration option.