Re: [RFC PATCH 00/78] Strict disable implicit fallthrough

[Manos Pitsidianakis]

On Fri, 13 Oct 2023 11:14, "Daniel P. Berrangé" <berrange@redhat.com> wrote:
> On Fri, Oct 13, 2023 at 10:47:04AM +0300, Emmanouil Pitsidianakis wrote:
> > Main questions this RFC poses
> > =============================
> >
> > - Is this change desirable and net-positive.
>
> Yes, IMHO it is worth standardizing on use of the attribute. The allowed
> use of comments was a nice thing by the compiler for coping with pre-existing
> code, but using the attribute is best long term for a consistent style.
>
> > - Should the `fallthrough;` pseudo-keyword be defined like in the Linux
> >   kernel, or use glib's G_GNUC_FALLTHROUGH, or keep the already existing
> >   QEMU_FALLTHROUGH macro.
>
> As a general rule, if glib provides functionality we aim o use that
> and not reinvent the wheel. IOW, we should just use G_GNUC_FALLTHROUGH.

I agree. My reasoning was:

- The reinvented wheel is only an attribute and not a big bunch of NIH 
 code
- The macro def in glib depends on the glib version you use
- G_GNUC_FALLTHROUGH looks kind of abrasive to my eye, while 
 `fallthrough` blends in with other switch keywords like break.
- C23 standardises fallthrough. We might not ever support C23 but it's 
 good to be consistent with standards and other, larger projects (linux 
 kernel).

I think these (except for myself finding G_GNUC_FALLTHROUGH ugly) make a 
strong case for not using the glib macro, personally. I'd be interested 
to know if there is a counterpoint to it: because I don't want this 
change to cause problems in the future.


Manos