Re: [PATCH 7/7] xen/device_tree: Fix MISRA C 2012 Rule 20.7 violations

[Xenia Ragiadakou <burzalodowa@xxxxxxxxx>]

On 8/22/22 14:48, Jan Beulich wrote:
> On 22.08.2022 12:43, Xenia Ragiadakou wrote:
> > On 8/22/22 12:59, Jan Beulich wrote:
> > > On 19.08.2022 21:43, Xenia Ragiadakou wrote:
> > > > In macros dt_for_each_property_node(), dt_for_each_device_node() and
> > > > dt_for_each_child_node(), add parentheses around the macro parameters that
> > > > have the arrow operator applied, to prevent against unintended expansions.
> > > Why is this relevant only when -> is used? For comparisons and the rhs of
> > > assignments it's as relevant, ad even for the lhs of assignments I doubt
> > > it can be generally omitted.
> > Yes, I agree with you but some older patches that I sent that were
> > adding parentheses around the lhs of the assignments were not accepted
> > and I thought that the rhs of the assignments as well these comparisons
> > fall to the same category.
> >
> > Personally, I would expect to see parentheses, also, around the macro
> > parameters that are used as the lhs or the rhs of assignments, the
> > operands of comparison or the arguments of a function.
> > Not only because they can prevent against unintentional bugs but because
> > the parentheses help me to identify more easily the macro parameters
> > when reading a macro definition. I totally understand that for other
> > people parentheses may reduce readability.
> Afair Julien's comments were very specific to the lhs of assignments.
> So at the very least everything else ought to be parenthesized imo.
So, IIUC, the only deviations from the MISRA C 2012 Rule 20.7 will be 
for macro parameters used as the lhs of assignments and function arguments?
This feels a bit of a hack to parenthesize the macro parameters that are 
used as the rhs of an assignment but not those used as the lhs.
From previous discussions on the topic, I understood that the 
parentheses are considered needed only when they eliminate operator 
precedence problems, while for the wrong parameter format bugs we can 
rely on the reviewers.
I think we need to decide if the rule will be applied as is and if not 
which will be the deviations along with their justification and add it 
to the document.
--
Xenia