Unhandled StackOverflowException when connecting to a HTTPSecureSocket

General
1

Was doing some testing when I got an unhandled exception. Here is the session log:

[quote]2019-03-29, 14:15:43 unhandled exception!!!
2019-03-29, 14:15:43 Buffer:
2019-03-29, 14:15:43 --------------------------
2019-03-29, 14:15:43 An error happened:
2019-03-29, 14:15:43 Window/Class:
2019-03-29, 14:15:43 Method/Event:
2019-03-29, 14:15:43 Error Message: A really unexpected error occurred!
2019-03-29, 14:15:43 Time: Friday, 29. March 2019 14:15:43 15439641
2019-03-29, 14:15:43 Type of Error: StackOverflowException
2019-03-29, 14:15:43 --------------------------
2019-03-29, 14:15:43 Stack:
2019-03-29, 14:15:43
Sub HTTPSecureSocket.Event_Connected()
Sub SSLSocket._Poll()
2019-03-29, 14:15:43 Stack done
2019-03-29, 14:15:43 ErrorReportWindow.Constructor
2019-03-29, 14:16:12 ErrorReportWindow.Constructor done[/quote]

Checking my code I only have 2 sockets: I don’t think that the Kaju socket makes the error. The other socket is very simple:

Socket = new HTTPSecureSocket Socket.Secure = True Socket.ConnectionType = HTTPSecureSocket.TLSv12

and

Socket.SetFormData("some dictionary") Socket.Post(some url)

Does anyone have an idea how to trap the exception? Xojo 2018r3, Mojave latest version.

2

I don’t think you can trap a stack overflow… usually this is caused by an unitentional recursion of some type

function test
test()
end function
3

No recursion for the socket.

I have been able to get the problem a couple of times now on Mojave. Never for High Sierra. The socket doesn’t do very much.

A workaround instead of trapping the error also would be fine.

4

the point is… somewhere there is recursion… perhaps not obvious… and perhaps not even socket related… but something somewhere is calling a piece of code without ever providing a proper exit

the problem with a stack overflow, is by the time it has happened, there are no resources let to allow it to be reported by Xojo

5

Do you poll either one ?
And do you call DoEvents anywhere in your app ?

6

[quote=431067:@Dave S]the point is… somewhere there is recursion… perhaps not obvious… and perhaps not even socket related… but something somewhere is calling a piece of code without ever providing a proper exit

the problem with a stack overflow, is by the time it has happened, there are no resources let to allow it to be reported by Xojo[/quote]
The IDE should break if you are running in debug mode though. Looking at the stack should make the recursion very obvious.

8

There is no recursion. In debug mode the app doesn’t go into the debugger as it would for a normal StackOverflow. I get a sort of empty debugger. When I click on run then I get the usual stuff that my app does for unhandled exceptions.

There is no polling and neither is there any DoEvents.

9

I think I read somewhere else that someone else is having trouble with Sockets on the latest Mojave. Do you have another machine running a different version of the macOS to test with?

10

@Sam Rowlands: yes, no problems on High Sierra with my main development machine. I also don’t have reports from customers about the problem.

11

In my opinion I would go as far as to say that perhaps Apple have broken something or changed something in a way which might be causing Xojo’s socket implementation to now have issues.

Like a crazy person, I keep hoping that one of these days, Apple is going to focus on stability, but I still get dissappointed to see this kind of stuff.

Incidentally, this morning I received a report from a customer where an application is borked where the interface is in dark mode. It’s like some of the controls are correctly using the color constants; while others are not.

It worries me to no end; I am almost ready to ship a brand new application that’s been completely rebuilt in the hopes for maximum Mojave compatibility.

12

I haven’t had time to look at the issue again.

In the latest version my app can download external images for emails. The old socket was a no-go because HTTP/1.1. The newer Xojo.Core socket made hard crashes. And Curl from MBS also makes hard crashes. I wasn’t so eager to go for the URLConnection.

And don’t get me started on AppTranslocation and the stupid permissions on Mojave.

13

[quote]The other socket is very simple:

Socket = new HTTPSecureSocket Socket.Secure = True Socket.ConnectionType = HTTPSecureSocket.TLSv12
and

Socket.SetFormData("some dictionary") Socket.Post(some url)
[/quote]
Any chance you could make a copy of your this socket and any code that touches it into a sample project so we could look at it?

14

The code is available at https://www.mothsoftware.com/downloads/GoogleAnalytics.zip .

A simple

dim theLogger as new LogToAnalytics theLogger.AddPageView("Window1")

is enough for testing. Of course, this doesn’t make a StackOverflow. Putting the code into a thread doesn’t change anything.

15

Can another plugin bork the rest of Xojo?

I have some intense fun with the Valentina plugin in the last weeks. The Valentina people have done several tries at doing a database diagnosis without showing the beachball - it either didn’t work or made a crash. I have now reverted back to a stable version of Valentina on this machine and I don’t get a StackOverflow anymore.

16

As a sidenote, maybe related. Since latest Mojave update i had crashes related to SSL connection using HTTPSecureSocket, but only if the App was Sandboxed.
I had to replace those Sockets with the new URLConnection. Crashes then vanished and Apple approved my App.

17

@Beatrix Willius — That weird StackOverflowException which does not look like a real one reminds me of Cocoa callbacks in macosLib. We usually had to insert “#pragma stackOverflowChecking false” at the beginning of any method which would be invoked from Cocoa in order to avoid fake StackOverflowExceptions.

May be worth a try

18

@Stephane Mons: Thomas T. mentioned something like this, too. As soon as I get the error again I’ll try your suggestion.