[Scilab-Dev] [oldEmptyBehaviour()] displaying a warning message in both Scilab 5 and Scilab 6 behavior

[antoine.monmayrant+scilab at laas.fr]

Here is an honest question to the scilab team (Clement in particular):

     What is so important with this change that you cannot drop it?

So far, it only seems to confuse or angry active developers and I can 
confirm that it occasionally confuse long time users like my self.
     I just tried to run  a script from one of my colleagues using 5.5.2:
         operation +: Warning adding a matrix with the empty matrix will 
give an empty matrix result.
         operation -: Warning adding a matrix with the empty matrix will 
give an empty matrix result.
         operation +: Warning adding a matrix with the empty matrix will 
give an empty matrix result.
         operation -: Warning adding a matrix with the empty matrix will 
give an empty matrix result.
         ... few 1000 lines ...
         operation +: Warning adding a matrix with the empty matrix will 
give an empty matrix result.
         operation -: Warning adding a matrix with the empty matrix will 
give an empty matrix result.
         operation +: Warning adding a matrix with the empty matrix will 
give an empty matrix result.
         operation -: Warning adding a matrix with the empty matrix will 
give an empty matrix result.
         at line   395 of function plot ( 
/home/myhome/softs/scilab-6.0.0-beta-1/share/scilab/modules/graphics/macros/plot.sci 
line 407 )
         at line   258 of executed file 
/home/myhome/mypath/Ngc21_LR_discretes.sce

To be honest, I don't see in this code where there might be a 'x+[]', it 
seems to appear further down the line, in scilab own macros.

Anyway, my point is not to criticize the work done on scilab 
development, but on this particular change, I can see now the issues it 
raises while I am clearly not convince that it will bring anything 
particularly key to scilab, apart from removing one oddity and its 
companion convenience.

Cheers,

Antoine


Le 04/07/2016 10:48 PM, Eric Dubois a écrit :
> Hello
>
> I suspect that a beta cycle is not enough and that some toolbox 
> developers or other users are not aware of this coming change. Once 
> again this is much shorter than previous changes, which were handled 
> much more smoothly by the Scilab team... Why still shorten the 
> adaptation time? Except to mark the difference with the predecessors?
>
> Happy to see that at least (and at last) someone does not find 
> compelling the case of changing this behaviour.
>
> By the way I have spent something like 2 weeks modifying my code and, 
> even if I hope having found most of the concerned cases, I am sure not 
> to have found all... and like Samuel the resulting code is sometimes 
> less clean than before. And I, have been obliged to stop ongoing 
> developments to do this stuff, which is from my point of view a bad 
> oiutcome.
>
> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> 
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>
>
> 2016-04-07 22:30 GMT+02:00 Samuel Gougeon <sgougeon at free.fr 
> <mailto:sgougeon at free.fr>>:
>
>     Hello,
>
>     Le 07/04/2016 10:16, Clément David a écrit :
>>     Hello (again) Scilab devs,
>>
>>     TLDR: I don't want to re-open the []+"" behavior change flame-war but just to remove a
>>            warning on working Scilab 6 code and ask you about the merge timing.
>>
>>
>>     After the []+"" behavior change, the oldEmptyBehaviour has been introduced by Pierre-Aimé to ease
>>     the transition from Scilab 5 to Scilab 6. This will help user transitioning using the beta version
>>     and thanks to that we also fix some issues in Scilab itself.
>>
>>     However, the current implementation display a warning in both Scilab 5 enforced and Scilab 6
>>     execution mode. I proposed a patchset [1] to remove the warning in the Scilab 6 execution mode but
>>     preserve it on the Scilab 5 mode (eg. after a call to oldEmptyBehaviour("on") ).
>>
>>     What's your thought about this change ? should we pass it now or after the 6.0.0 release ? Is the
>>     beta cycle sufficient enough to manage the behavior change ?
>
>     I am afraid that i do not catch all what you mean.
>     With "Scilab 5 enforced execution mode", do you mean in Scilab 6
>     with oldEmptyBehaviour("on") mode?
>     So, instead of using this mode to still ACCEPT and NOT warn users
>     whether []+a is met, it would warn users,
>     while in oldEmptyBehaviour("off"), meeting []+a would no longer
>     warn users?
>
>     If what i understand above is right: imo, enabling users to ignore
>     this warning by masking it would be
>     quite "dangerous", because changing this behavior has consequences
>     as serious as quiet.
>
>     BTW:
>     * This would be a first case of Switch-warning-on-specific-case
>     application.
>        To be discussed in the "upgrade warning() thread"
>     * The discussion with Eric and other users is not a flame-war. The
>     more i modified my code about this feature,
>        the more i thought that even if "[]+a == a" is not "logical",
>     it is very handy, it does not hurt, and it prevents nothing.
>        Removing it compels to add as many if/then/else. /And what for/?
>
>     Best regards
>     Samuel
>
>
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