[PATCH v2] virProcessGetStatInfo: add a comment describing why we can not report error

[Ani Sinha]

Pinging again in case there is any interest ..

On Tue, Jan 25, 2022 at 4:34 PM Ani Sinha <ani at anisinha.ca> wrote:
>
> ping ...
>
> On Fri, 21 Jan 2022, Ani Sinha wrote:
>
> > virProcessGetStatInfo() currently is unable to report error conditions because
> > that breaks libvirt's public best effort APIs. We add a comment in the function
> > to indicate this. Adding comment here prevents others from going down the path
> > of reporting error conditions in this functions in the future. It also reminds
> > us that at some point in the future we need to fix the code so that this
> > limitations no longer exists.
> >
> > Please also see commit
> > 105dace22cc7 ("Revert "report error when virProcessGetStatInfo() is unable to parse data"")
> >
> > Signed-off-by: Ani Sinha <ani at anisinha.ca>
> > ---
> >  src/util/virprocess.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> >
> > diff --git a/src/util/virprocess.c b/src/util/virprocess.c
> > index b559a4257e..9422829b8b 100644
> > --- a/src/util/virprocess.c
> > +++ b/src/util/virprocess.c
> > @@ -1784,6 +1784,12 @@ virProcessGetStatInfo(unsigned long long *cpuTime,
> >          virStrToLong_ullp(proc_stat[VIR_PROCESS_STAT_STIME], NULL, 10, &systime) < 0 ||
> >          virStrToLong_l(proc_stat[VIR_PROCESS_STAT_RSS], NULL, 10, &rss) < 0 ||
> >          virStrToLong_i(proc_stat[VIR_PROCESS_STAT_PROCESSOR], NULL, 10, &cpu) < 0) {
> > +        /* This function can not report error at present. Reporting error here
> > +         * causes some of libvirt's best effort public APIs to fail. This
> > +         * resuts in external API behavior change. Until we can fix this in
> > +         * a way so that public API behavior remains unchanged, we can only
> > +         * write a warning log here.
> > +         */
> >          VIR_WARN("cannot parse process status data");
> >      }
> >
> > --
> > 2.25.1
> >
> >