Re: [MACTCL] Crash when using two consecutive mainloops

[<chr...@gm...>]

On 8/12/23 at 2:23 AM, Aivar Annamaa wrote:

> Hi!
>
> My Tkinter application (using Tk 8.6.13) uses two independent windows
> during first run -- if it sees the configuration file is missing, it first
> presents a small window (an instance of tkinter.Tk) for collecting a couple
> of user preferences, then closes it and only then presents the main window
> (another tkinter.Tk).
>
> In Linux and Windows this works nicely, but in macOS (e.g. Intel Catalina
> or Arm Ventura), when two windows are used like this, the process crashes
> with segmentation fault when the user opens a menu or invokes a file dialog
> in the main window. Here is the Python fault report:
> https://pastebin.com/pjiCVamm and this is macOS report:
> https://pastebin.com/isaNMb5V
>
> I've considered restarting the process after creating the configuration
> file (thus using single mainloop per process), but it would be an extra
> hassle.
>
> Any ideas how to overcome problem this without changing the overall
> approach? I tried assigning different window classes for each window but it
> didn't help.
>
> Best regards,
> Aivar



Hello Aivar,

This crash has been reported previously, including by many Tkinter users. I posted an explanation of this crash and a proposed fix for it at
https://core.tcl-lang.org/tk/info/ef5d3e29a4
however it has yet to be reviewed by the Tk Aqua developers.

Although some users have reported workarounds for this issue, I am not certain how reliable they actually are, or whether they apply to your use case. However, what I do know is that this issue can only occur once the first created root/main window, i.e. the first tkinter.Tk() instance, is destroyed. So the workaround I might suggest is to create only one tkinter.Tk() instance, and then use it to create additional Toplevels as needed, rather than creating new tkinter.Tk() instances.

Also, as I have said to others who posted here, the tcl-mac list is far less popular than it once was, and I would not recommend using it due to the likelihood of posts going unnoticed.


Hope this helps,

Christopher A. Chavez