Bug #128654 for Tcl-pTk: Errors when calling Perl exit from Tk sub

Wed Feb 27 01:34:27 2019 CAC [...] cpan.org - Ticket created

Subject:

Errors when calling Perl exit from Tk sub

Using Tcl::pTk 0.95 and Tcl/Tk 8.6.9, but I'm not aware this doesn't apply to earlier Tcl::pTk or Tcl/Tk.

According to Mastering Perl/Tk §1.4.1 "exit Versus destroy", Perl/Tk redefines exit; to my knowledge, Tcl::pTk does not do this. Currently, the File > Quit command in the widgetTclpTk demo invokes sub { exit }. Clicking File > Quit causes the following errors:

- on macOS XQuartz, causes "Segmentation fault 11" (will attach crash log)

- on Fedora 29, causes the following error (only the opcode values are consistent):

X Error of failed request: RenderBadPicture (invalid Picture parameter)

Major opcode of failed request: 138 (RENDER)

Minor opcode of failed request: 7 (RenderFreePicture)

Picture id in failed request: 0x16000e2

Serial number of failed request: 1961

Current serial number in output stream: 2049

- on FreeBSD 13.0 (GhostBSD 18.12, Project Trident PR2), causes "Bus error".

Nothing interesting happens on macOS Aqua or Windows.

Maybe exit should be redefined by Tcl::pTk, but how? Should it just be a shorthand for destroying the main window (…->interp->Eval('destroy .')), or are there enough situations where that shouldn't be what is done?

Though as Mastering Perl/Tk points out, the more clear alternative (and workaround for this issue) is to just use $MW->destroy instead of exit.

Thu Feb 28 03:18:22 2019 CAC [...] cpan.org - Correspondence added

On Wed Feb 27 00:34:27 2019, CAC wrote:
Show quoted text

> Using Tcl::pTk 0.95 and Tcl/Tk 8.6.9, but I'm not aware this doesn't
> apply to
> earlier Tcl::pTk or Tcl/Tk. According to Mastering Perl/Tk §1.4.1
> "exit Versus
> destroy", Perl/Tk redefines exit; to my knowledge, Tcl::pTk does not
> do this.
> Currently, the File > Quit command in the widgetTclpTk demo invokes
> sub { exit
> }. Clicking File > Quit causes the following errors: - on macOS
> XQuartz, causes
> "Segmentation fault 11" (will attach crash log) - on Fedora 29, causes
> the
> following error (only the opcode values are consistent):
> X Error of failed request: RenderBadPicture (invalid Picture
> parameter) Major
> opcode of failed request: 138 (RENDER) Minor opcode of failed request:
> 7
> (RenderFreePicture) Picture id in failed request: 0x16000e2 Serial
> number of
> failed request: 1961 Current serial number in output stream: 2049 - on
> FreeBSD
> 13.0 (GhostBSD 18.12, Project Trident PR2), causes "Bus error".
> Nothing
> interesting happens on macOS Aqua or Windows. Maybe exit should be
> redefined by
> Tcl::pTk, but how? Should it just be a shorthand for destroying the
> main window
> (…->interp->Eval('destroy .')), or are there enough situations where
> that
> shouldn't be what is done? Though as Mastering Perl/Tk points out, the
> more
> clear alternative (and workaround for this issue) is to just use $MW-

> >destroy

> instead of exit.

Attached crash log for macOS XQuartz.

Subject:

perl5.28_2019-02-25-211433_cacbook.crash

Download perl5.28_2019-02-25-211433_cacbook.crash
application/octet-stream 19.1k

Message body not shown because it is not plain text.

Thu May 09 23:13:33 2019 CAC [...] cpan.org - Correspondence added

Another user encountered this a while back in Tcl::Tk: https://www.perlmonks.org/?node_id=1191134 (I left a reply just now).

While I do not think Tcl::Tk would worry about being compatible with Perl/Tk's exit behavior, and would probably suggest using destroy instead if exit causes problems, Tcl::pTk however may want to support existing exit usage, or it really needs to document it as unsupported in favor of using destroy. Because of the difference in behavior between exit and destroy, making exit do the same as destroy I think is not desirable. But based on what I have read so far of Perl/Tk's exit implementation, if it is possible to support it in Tcl::pTk, then it may require using XS/C API and in turn involve Tcl.pm.

Thu May 09 23:52:22 2019 CAC [...] cpan.org - Correspondence added

On Thu May 09 22:13:33 2019, CAC wrote:
Show quoted text

> Another user encountered this a while back in Tcl::Tk:
> https://www.perlmonks.org/?node_id=1191134 (I left a reply just now).

Also note that they were using Tk Aqua, and were getting a segmentation fault; I have yet to reproduce this error on Aqua.

Sat Mar 07 03:14:13 2020 CAC [...] cpan.org - Reference by ticket #128804 added