Re: [PATCH] docs/misra: add R13.2 and R18.2 to rules.rst

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Wed, 31 Jul 2024, Jan Beulich wrote:
> On 31.07.2024 01:30, Stefano Stabellini wrote:
> > --- a/docs/misra/rules.rst
> > +++ b/docs/misra/rules.rst
> > @@ -462,6 +462,15 @@ maintainers if you want to suggest a change.
> >       - Initializer lists shall not contain persistent side effects
> >       -
> >  
> > +   * - `Rule 13.2 
> > <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_13_02.c>`_
> > +     - Required
> > +     - The value of an expression and its persistent side-effects shall
> > +       be the same under all permitted evaluation orders
> > +     - Be aware that the static analysis tool Eclair might report
> > +       several findings for Rule 13.2 of type "caution". These are
> > +       instances where Eclair is unable to verify that the code is valid
> > +       in regard to Rule 13.2. Caution reports are not violations.
> 
> Which doesn't make clear what our take is towards new code people may
> submit.

Good point, see my comment below


> > @@ -583,6 +592,15 @@ maintainers if you want to suggest a change.
> >         submitting new patches please try to decrease the number of
> >         violations when possible.
> >  
> > +   * - `Rule 18.2 
> > <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_18_02.c>`_
> > +     - Required
> > +     - Subtraction between pointers shall only be applied to pointers
> > +       that address elements of the same array
> > +     - Be aware that the static analysis tool Eclair might report
> > +       several findings for Rule 18.2 of type "caution". These are
> > +       instances where Eclair is unable to verify that the code is valid
> > +       in regard to Rule 18.2. Caution reports are not violations.
> 
> And while the same wording is used here, I think it is pretty clear for
> this that we'd reject changes where bad subtractions are used. IOW even
> more so important to clarify the (possibly different) positions on what
> is going to be added into the code base.

In both of these cases, we would reject code that doesn't follow R13.2
and R18.2. I'll change it to the following:


Be aware that the static analysis tool Eclair might report several
findings for Rule 18.2 of type "caution". These are instances where
Eclair is unable to verify that the code is valid in regard to Rule
18.2. Caution reports are not violations. Regardless, new code is
expected to follow this rule.