XPC+MSCrashes = real user app featurebug about appcenter-sdk-apple

[bmourat]

Hey @ianbytchek
I've played with this a little and it seems like it is not the crashes module. If you call start with Analytics module, and i presume any other module, it will happen also. The reason is that while sendind start service log, sdk tries to determine screen size here. And after this call NSRunningApplication.current is assigned a new object. You can reproduce this by inserting call to NSScreen.main between print statements, like this:

Swift.print(NSRunningApplication.current.processIdentifier)
NSScreen.main
Swift.print(NSRunningApplication.current.processIdentifier)

[iby]

Thanks for figuring this out! This is interesting! My curiosity is 💯 satisfied.

[iby]

This is also observed when changing application type via ApplicationServices api, main.swift file below shows what happens. The same affect can be achieved with creating a copy of NSApplication, which does this internally.

// main.swift
import AppKit.NSRunningApplication
import ApplicationServices.HIServices

Swift.print(NSRunningApplication.current)
var psn: ProcessSerialNumber = .init(highLongOfPSN: 0, lowLongOfPSN: UInt32(kCurrentProcess))
TransformProcessType(&psn, UInt32(kProcessTransformToBackgroundApplication))
// _ = NSApplication() // Or just do this for the same effect…
Swift.print(NSRunningApplication.current)

AppCenter and PLCrashReporter don't appear to use the above api. What's the catch?

[ElektrojungeAtWork]

Hi @ianbytchek,
this is interesting. We need to look at this more closely.
Any chance you can send us a full stacktrace through support(intercom, the blue button on the App Center portal)?

[iby]

There's no crash – if I understood you correctly about the stacktrace? What I'm saying is starting AppCenter with crashes changes the application type in some untraceable way. To check this behaviour simply create a console app and put this inside the main.swift:

Swift.print(NSRunningApplication.current) // <NSRunningApplication: 0x608000111040 ((null) - -1)>
MSAppCenter.start(MSAppCenter.identifier, withServices: [MSCrashes.self])
Swift.print(NSRunningApplication.current) // <NSRunningApplication: 0x6040001049b0 (com.my.app - 52214)>

I'd like to know how AppCenter does it without any obvious api calls.

[ElektrojungeAtWork]

Oooops, I somehow misunderstood your message here. Sorry.
I didn't find the time to check this last week, we'll get back in touch as soon as I know more. Making the process available might actually be unintentional but we need to check 😇

[ElektrojungeAtWork]

Hi @ianbytchek,

sorry for the long wait. I've meant to investigate but just didn't find the time. I've created a bug for this and we will triage it accordingly.