Re: input validation in C++ internal functions

[Juan Pablo Carbajal]

On Fri, May 23, 2014 at 11:10 AM, Andreas Weber <address@hidden> wrote:
> Am 22.05.2014 12:41, schrieb Juan Pablo Carbajal:
>> On Thu, May 22, 2014 at 10:10 AM, Andreas Weber <address@hidden> wrote:
>>> Am 05.05.2014 19:24, schrieb Jordi Gutiérrez Hermoso:
>>>> On Mon, 2014-05-05 at 16:39 +0100, Michael D. Godfrey wrote:
>>>>> On 05/05/2014 07:47 AM, Andreas Weber wrote:
>>>>>> In my humble optinion no function should segfault when accessible from
>>>>>> the octave interpreter.
>>>>> I am pretty sure that Jordi agrees with this, and it s a long-standing
>>>>> principle that Octave should never seg fault.
>>>> Yeah, it's a bug, although I consider it a minor one, since it's in
>>>> internal functions.
>>>>
>>>> My complaint at the time was that almost none of the internal C++
>>>> functions do any argument-checking. I'm not against this sort of
>>>> patch, but I am against cluttering every internal C++ function with
>>>> argument-checking boilerplate code. Andy's patch in question at the
>>>> moment looks reasonable to me, but it's a stopgap around a larger
>>>> problem.
>>> Pushed to stable
>>> http://hg.savannah.gnu.org/hgweb/octave/rev/5e99fd6ea758 after
>>> discussion in IRC. -- Andy
>>>
>>>
>> Is it possible to add a error_id in the error message?
>> I suggest
>>
>> error ("Octave:invalid-input-arg", "__calc_dimensions__: expecting
>> graphics handle as only argument");
>>
>> ids and their description can be retrieved using error_ids in the  octave 
>> prompt
>
> Dear Juan Pablo,
> I guess this should be "error_with_id
> ("Octave:invalid-input-arg",......", right?
>
> When grepping through libinterp/corefcn/ I see than only a few files
> uses error_with_id (most in cellfun.cc). My intial question was intended
> to figure out how we should handle input-checking in internal C++ code.
>
> I understand Jordi that he doesn't want to clutter internal functions
> with argument checking, nevertheless to my understanding they should
> never segfault. I guess a better way would be to do and index checking
> in octave_value_list so that args() out of bounds raise and error but
> this is just a wild guess from me.
>
> To your question: Of course I can add  error_id but in my optinion is,
> that this is controversial to the previously "do only the absolutely
> necessary input checks" conclusion and I don't want to start another
> controversy. I hope this is okay for you. -- Andy
>
>

IMHO, I do not think the id in the error clutters more than the error
without the id. And the id help filtering them.
But do as is more convenient for you. Eventually, I will do another
pass adding id to errors.