Re: [PATCH] Config.mk: drop -Wdeclaration-after-statement

[Julien Grall <julien@xxxxxxx>]

Hi Jan,

On 30/11/2023 08:36, Jan Beulich wrote:
> On 29.11.2023 14:10, Anthony PERARD wrote:
> > On Wed, Nov 29, 2023 at 11:47:24AM +0100, Julien Grall wrote:
> > > + Anthony for the tools
> > > + Juergen for Xenstored
> > >
> > > On 29/11/2023 11:34, Alexander Kanavin wrote:
> > > > On 11/29/23 08:51, Jan Beulich wrote:
> > > >
> > > > > On 28.11.2023 18:47, Alexander Kanavin wrote:
> > > > > > Such constructs are fully allowed by C99:
> > > > > > https://gcc.gnu.org/onlinedocs/gcc-12.2.0/gcc/Mixed-Labels-and-Declarations.html#Mixed-Labels-and-Declarations
> > > > > There's more to this: It may also be a policy of ours (or of any
> > > > > sub-component)
> > > > > to demand that declarations and statements are properly separated.
> > > > > This would
> > > > > therefore need discussing first.
> > > > The error is coming from python 3.12 headers and not from anything in
> > > > xen tree, no? As you don't have control over those headers, I'm not sure
> > > > what other solution there could be.
> > > We seem to add -Wno-declaration-after-statement for some components in
> > > tools/. So one possibility would be to move the flags to an hypervisor
> > > specific makefile (in xen/).
> > You mean xen/Makefile I hope.
> >
> > > Anthony/Juergen, do you have any concern if the tools are built without
> > > -Wdeclaration-after-statement?
> > I don't, and as you said, there's already quite a few
> > -Wno-declaration-after-statement.
> >
> > It can be nice to add a new variable in the middle of a function, it's
> > like creating a new scope without adding extra indentation (if we wanted
> > a new scope, we would need {} thus the intend).
> To be clear, I wouldn't mind this in the hypervisor either. But then I also
> don't see why we should further request people to separate declarations
> from statements in an easily noticeable way. Thing is that imo something
> like this wants spelling out in ./CODING_STYLE.
So I agree that if we were to remove -Wdeclaration-after-statement then 
we should also update the CODING_STYLE. However, I am not entirely sure 
I would want to mix code and declaration in the hypervisor.
Anyway, I think this is a separate discussion from resolving the 
immediate problem (i.e. building the python bindings).
So for now, I think it would make sense to push the 
-Wdeclaration-after-statement to the tools.
@Alexander, are you going to send a new version? If not, I would be 
happy to do it.
Cheers,

--
Julien Grall