[MAUI] Breadcrumbs occasionally applying to event out of order

[Fwang36]

Tracking issue for:

• Add auto crumb for significantTimeChangeNotification sentry-cocoa#5161

Environment

SaaS (https://sentry.io/)

Steps to Reproduce

Filing this issue on behalf of a user in this Zendesk support ticket

SDK - dotnet MAUI 5.5.0
OS - iOS 17.1.1

The Breadcrumbs array seems to sometimes be out of order and is not sorted according to the timestamps of the breadcrumb. Here is an example from the user's event JSON -

Note how the breadcrumb I highlighted for device.connectivity is timestamped before the started Breadcrumb Tracking timestamp. This example here was captured by the Cocoa SDK.

Expected Result

They should be in timestamp order

Actual Result

They are not in timestamp order. This causes the UI in Sentry to display them out of order as well.

Product Area

Unknown

Link

No response

DSN

No response

Version

No response

[bruno-garcia]

Is there an example event? Curious if this is coming from a native SDK, such as sentry.cocoa.dotnet or sentry.java.android.dotnet.
In which case my be related to how we bind the .NET breadcrumb scope to native.

[bruno-garcia]

@Fwang36 said:

Yes, the example event is the one I posted above, and it is a sentry.cocoa.dotnet event

[bruno-garcia]

Reading the code in the cocoa SDK, it comes from here:

https://github.com/getsentry/sentry-cocoa/blob/bfcfc62c15b1531674c50fb306b57fbc7fbf776f/Sources/Sentry/SentryBreadcrumbTracker.m#L158-L162

This specific breadcrumb doesn't come from the .NET SDK itself though: https://github.com/search?q=repo%3Agetsentry%2Fsentry-dotnet%20device.connectivity&type=code

So it seems to me it could be an issue in the cocoa SDK. (they are on sentry.cocoa: 8.39.0)
@philipphofmann are you aware of any reason why this could happen?

[bruno-garcia]

Note, the Breadcrumb tracking crumb's timestamp is actually after the 2nd and 3d device.connectivity ones:

[philipphofmann]

These breadcrumbs stem from the SentryReachability. The SentryReachability posts connectivity changes on a BG thread, which uses a serial dispatch queue, meaning that if such chance occurs shortly after each other the breadcrumbs should be in order, but there could be an edge case we're missing of course, but I didn't find one after a quick investigation. I'm actually surprised that the Sentry UI doesn't automatically sort these by timestamp.

[philipphofmann]

A positive side effect of investigating this issue was finding slightly blocking the main thread on init in the HttpTransport of the Cocoa SDK getsentry/sentry-cocoa#5138.

[bruno-garcia]

I'm aware Sentry doesn't order by timestamp by default.
I have mixed feelings about doing that, because in cases where the device travels to a new timezone, things would become incorrect and misleading.

I find that in its current form, at least it lets us find areas where the order doesn't match the timestamp and we can assess what we want to do.