Bug 57260 - Random crash when binding
Summary: Random crash when binding
Alias: None
Product: Forms
Classification: Xamarin
Component: Forms ()
Version: 2.3.4
Hardware: Macintosh Mac OS
: --- normal
Target Milestone: ---
Assignee: Jimmy [MSFT]
Depends on:
Reported: 2017-06-07 23:04 UTC by Jim Bennett
Modified: 2017-06-12 22:42 UTC (History)
2 users (show)

Is this bug a regression?: ---
Last known good build:

Stack trace of crash (9.82 KB, text/rtf)
2017-06-07 23:04 UTC, Jim Bennett
Stack trace of crash on Android (4.65 KB, text/rtf)
2017-06-12 22:42 UTC, Jim Bennett

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Description Jim Bennett 2017-06-07 23:04:53 UTC
Created attachment 22758 [details]
Stack trace of crash

We've seen a crash happen in our app just on iOS a couple of times when binding happens during a UI update. It looks like the binding tries to get a value and crashes, maybe because the binding context is not there as the UI is changing. It's not reproducible, just has happened a couple of times during testing.

A stack trace is attached - it would be good if a binding operation was able to fail without killing the app.
Comment 1 Jimmy [MSFT] 2017-06-08 20:29:41 UTC
My initial thought after seeing the crash log is that there might be a handler attached to an object that is still receiving events and trying to access an object that might already be collected.

What version of Xamarin.Forms are you using? Did you start seeing the crash after updating to this version? Have you noticed any patterns of when it does occur, such as after navigating to another page? Also, are you only seeing this on iOS, or on the platforms as well?
Comment 2 Jim Bennett 2017-06-08 21:41:47 UTC
That was my thoughts as well - just a bad timing issue, a property change was raised but the object was GC'd before it could get the value.

We've seen it twice so far, just on iOS using It's a rare crash and not reproducible so it may have been an issue with older versions but we didn't see it. It happens when navigating to a different page.
Comment 3 Jim Bennett 2017-06-12 22:42:53 UTC
Created attachment 22841 [details]
Stack trace of crash on Android

I'm also seeing a similar crash on Android - same thing, data update when navigating. It's impossible to ensure data is not updated when navigating so it would be good for the binding to not crash the app if the widget is disposed.