#411 Axis warning from tcl8.6

[Sebastian Kuzminsky]

Axis gets tcl errors in Debian Jessie, with tcl 8.6.2+dfsg-1.

Build 2.6 (i used commit cbca1a21) for run-in-place, start sim/axis/axis.ini, hit F1 to reset the Estop, hit F2 to turn the machine on, and it prints this error:

TCL error in asynchronous code:
wrong # args: should be ".toolbar.program_step cmd ?arg ...?"
    while executing
".toolbar.program_step"
    invoked from within
"if {$::last_interp_state != $::INTERP_IDLE || $::last_task_state != $::task_state} {
                #puts "abount to squawk"
                set_mode_from_tab
           ..." 
    (procedure "update_state" line 45)
    invoked from within
"update_state"
    ("after" script)
Shutting down and cleaning up LinuxCNC...

This exact code runs just fine with tcl 8.4 and 8.5 in pre-Jessie versions of Debian.

[Sebastian Kuzminsky]

aspect and miguel on #tcl had some helpful advise

miguel said:

does linuxcnc use any C code, or C extension? Tcl8.6 has big
changes that are not visible to scripts or "correct" C extensions
(modulo bugs, of course), but that misbehave for some undocumented
idioms that previously ran fine
so the problem is likely caused by C code that runs afoul of the nre

[Sebastian Kuzminsky]

We build two tcl extensions (i'm counting things that match tcl/*.so) from C code:

• hal.so, from src/hal/utils/halsh.c
• linuxcnc.so, from src/emc/usr_intf/emcsh.cc

[Sebastian Kuzminsky]

axis does not load tcl/hal.so, but it does load tcl/linuxcnc.so.

The main axis script is written in python, and it imports lib/python/rs274/options.py, which sources tcl/linuxcnc.tcl into the tk root window, and linuxcnc.tcl loads tcl/linuxcnc.so.

But apparently axis doesn't actually use linuxcnc.so, at least not for the early parts i tested. I can comment out the line in tcl/linuxcnc.tcl that loads tcl/linuxcnc.so, and rm tlc/*.so, and axis starts up without complaint.

And it still prints that tcl warning when i hit F1, F2....

So it is something else that is going on here.

[Sebastian Kuzminsky]

Matche (W. Martinjak) says:

Putting a simple statement at the first line in the proc update_state.
At least it works for me.
And my conclusion is the same as yours.... I have no idea why. :-)

Michael Büsch supplied the patch attached to this comment (which implements this suggestion) and reports that it works for him too.

[Sebastian Kuzminsky]

mozmck reports on irc that Axis works with the tcl in Ubuntu Trusty (14.04), 8.6.1-4ubuntu1:

http://tom-itx.no-ip.biz:81/~tom-itx/irc/logs/%23linuxcnc-devel/2015-02-12.html#12:13:08

http://tom-itx.no-ip.biz:81/~tom-itx/irc/logs/%23linuxcnc-devel/2015-02-12.html#13:12:58

[Jeff Epler]

Debian experimental libtcl8.6=8.6.4+dfsg-1 also does not exhibit this problem. However, since this version is not likely to be in Debian Jessie when it is released, I intend to apply a "shake a stick at the problem" fix to 2.6 and up

[Jeff Epler]

Believed fixed by http://git.linuxcnc.org/?p=linuxcnc.git;a=commitdiff;h=5a0272d