Re: [XEN PATCH] xen: add explicit comment to identify notifier patterns

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Mon, 17 Jun 2024, Jan Beulich wrote:
> On 17.06.2024 11:49, Federico Serafini wrote:
> > MISRA C Rule 16.4 states that every `switch' statement shall have a
> > `default' label" and a statement or a comment prior to the
> > terminating break statement.
> > 
> > This patch addresses some violations of the rule related to the
> > "notifier pattern": a frequently-used pattern whereby only a few values
> > are handled by the switch statement and nothing should be done for
> > others (nothing to do in the default case).
> > 
> > No functional change.
> > 
> > Signed-off-by: Federico Serafini <federico.serafini@xxxxxxxxxxx>
> 
> I guess I shouldn't outright NAK this, but I certainly won't ack it. This
> is precisely the purely mechanical change that in earlier discussions some
> (including me) have indicated isn't going to help safety. However, if
> others want to ack something purely mechanical like this, then my minimal
> requirement would be that somewhere it is spelled out what falls under

I know there is a new version of this patch on xen-devel but I just
wanted to add that although it is true that this patch taken on its own
it does not improve safety, it does improve safety because it enables us
to go down to zero violations on rule 16.4 and then make the rule 16.4
blocking in the gitlab-ci ECLAIR job.