Re: [Qemu-arm] [Qemu-devel] [PATCH] Use error_fatal to simplify obvious fatal errors

[Marcel Apfelbaum]

On 12/10/2015 02:34 PM, Markus Armbruster wrote:
> Marcel Apfelbaum <address@hidden> writes:
>
> > On 12/10/2015 12:19 PM, Markus Armbruster wrote:
> > > Done with this admittedly crude Coccinelle semantic patch with manual
> > > burial of dead Error * variables squashed in:
> > >
> > >       @@
> > >       identifier FUN;
> > >       expression ERR, EC;
> > >       @@
> > >       -    FUN(&ERR);
> > >       -    if (ERR != NULL) {
> > >       -        error_report_err(ERR);
> > >       -        exit(EC);
> > >       -    }
> > >       +    FUN(&error_fatal);
> > >       @@
> > >       identifier FUN;
> > >       expression ARG1, ERR, EC;
> > >       @@
> > >       -    FUN(ARG1, &ERR);
> > >       -    if (ERR != NULL) {
> > >       -        error_report_err(ERR);
> > >       -        exit(EC);
> > >       -    }
> > >       +    FUN(ARG1, &error_fatal);
> > >       @@
> > >       identifier FUN;
> > >       expression ARG1, ARG2, ERR, EC;
> > >       @@
> > >       -    FUN(ARG1, ARG2, &ERR);
> > >       -    if (ERR != NULL) {
> > >       -        error_report_err(ERR);
> > >       -        exit(EC);
> > >       -    }
> > >       +    FUN(ARG1, ARG2, &error_fatal);
> > >       @@
> > >       identifier FUN;
> > >       expression ARG1, ARG2, ARG3, ERR, EC;
> > >       @@
> > >       -    FUN(ARG1, ARG2, ARG3, &ERR);
> > >       -    if (ERR != NULL) {
> > >       -        error_report_err(ERR);
> > >       -        exit(EC);
> > >       -    }
> > >       +    FUN(ARG1, ARG2, ARG3, &error_fatal);
> > >       @@
> > >       identifier FUN;
> > >       expression RET, ERR, EC;
> > >       @@
> > >       -    RET = FUN(&ERR);
> > >       -    if (ERR != NULL) {
> > >       -        error_report_err(ERR);
> > >       -        exit(EC);
> > >       -    }
> > >       +    RET = FUN(&error_fatal);
> > >       @@
> > >       identifier FUN;
> > >       expression RET, ARG1, ERR, EC;
> > >       @@
> > >       -    RET = FUN(ARG1, &ERR);
> > >       -    if (ERR != NULL) {
> > >       -        error_report_err(ERR);
> > >       -        exit(EC);
> > >       -    }
> > >       +    RET = FUN(ARG1, &error_fatal);
> > >       @@
> > >       identifier FUN;
> > >       expression RET, ARG1, ARG2, ERR, EC;
> > >       @@
> > >       -    RET = FUN(ARG1, ARG2, &ERR);
> > >       -    if (ERR != NULL) {
> > >       -        error_report_err(ERR);
> > >       -        exit(EC);
> > >       -    }
> > >       +    RET = FUN(ARG1, ARG2, &error_fatal);
> > >       @@
> > >       identifier FUN;
> > >       expression RET, ARG1, ARG2, ARG3, ERR, EC;
> > >       @@
> > >       -    RET = FUN(ARG1, ARG2, ARG3, &ERR);
> > >       -    if (ERR != NULL) {
> > >       -        error_report_err(ERR);
> > >       -        exit(EC);
> > >       -    }
> > >       +    RET = FUN(ARG1, ARG2, ARG3, &error_fatal);
> > >       @@
> > >       type T;
> > >       identifier FUN, RET;
> > >       expression ERR, EC;
> > >       @@
> > >       -    T RET = FUN(&ERR);
> > >       -    if (ERR != NULL) {
> > >       -        error_report_err(ERR);
> > >       -        exit(EC);
> > >       -    }
> > >       +    T RET = FUN(&error_fatal);
> > >       @@
> > >       type T;
> > >       identifier FUN, RET;
> > >       expression ARG1, ERR, EC;
> > >       @@
> > >       -    T RET = FUN(ARG1, &ERR);
> > >       -    if (ERR != NULL) {
> > >       -        error_report_err(ERR);
> > >       -        exit(EC);
> > >       -    }
> > >       +    T RET = FUN(ARG1, &error_fatal);
> > >       @@
> > >       type T;
> > >       identifier FUN, RET;
> > >       expression ARG1, ARG2, ERR, EC;
> > >       @@
> > >       -    T RET = FUN(ARG1, ARG2, &ERR);
> > >       -    if (ERR != NULL) {
> > >       -        error_report_err(ERR);
> > >       -        exit(EC);
> > >       -    }
> > >       +    T RET = FUN(ARG1, ARG2, &error_fatal);
> > >       @@
> > >       type T;
> > >       identifier FUN, RET;
> > >       expression ARG1, ARG2, ARG3, ERR, EC;
> > >       @@
> > >       -    T RET = FUN(ARG1, ARG2, ARG3, &ERR);
> > >       -    if (ERR != NULL) {
> > >       -        error_report_err(ERR);
> > >       -        exit(EC);
> > >       -    }
> > >       +    T RET = FUN(ARG1, ARG2, ARG3, &error_fatal);
> >
> > That's so cool!
>
> I'm afraid my sledgehammer approach to Coccinelle would make its
> inventors wince...
>
> > Isn't it the time to have our own Coccinelle directory
> > with scripts like this?
>
> Could do that if there's interest.
>
> >                          And to make them part of make check?
>
> I'm afraid that's not practical.  spatch solves a difficult problem, and
> takes its own sweet time to do it.

So it takes a long time to run. We could make it depend on an environment 
variable,
so at least the maintainers will run it :)

My point is, now we *could* have a guarantee that if anyone uses the old
way, we can catch it in time. It can be easily lost in the review process.

Anyway, it was only a thought.
Thanks,
Marcel


> > Is a pity to have them lost into a git comment...