Shell.Completed fires after destructor

General
1

On Windows, run the following code:

[code]
class my_shell_subclass (inherits shell)
event Completed
break

sub Destructor
break
end sub

Window1.PushButton1.Action
dim a as new my_shell_subclass
a.mode=1
a.execute"notepad"[/code]

I find that my_shell_subclass.Completed fires after that object has destructed.

Is this safe, or is code in the Completed event potentially referencing an object which may or may not still exist?

2

I’d say its a bug, technically notepad hasn’t completed even though it fires during destruction so the values of self in Completed are garbage once the Destructor has run.

I’d suggest popping a feedback in and code around it by keeping a in scope until you can clean up nicely.

I’d then test that solution in 2019r1 beta because I had a spectacular crash when testing this in there :slight_smile:

3

Perhaps the superclass Destructor is calling Shell.Close internally? Superclass destructors run after subclass destructors have returned.

4

Is your shell object going out of scope before it completes?

5

I would go with Tim’s note and make sure that you’re not leaving the scope that initialized the shell instance before it has completed. I’ve run into this before where I was launching may shells in threads.

6

Just for the record if anyone’s search hits this later, I found a different bug when testing this <https://xojo.com/issue/55312> (pre-release view only sorry as I found the bug originally in beta) I don’t know if they want the two issues separated or if they’ll both be fixed at the same time so it might need another bug report for the OP.