Re: [RFC PATCH 00/21] C99: show meaningful <file>:<line> in trace2 via macros

[Taylor Blau <me@ttaylorr.com>]

On Tue, Nov 16, 2021 at 07:58:01PM +0100, Ævar Arnfjörð Bjarmason wrote:
> On Tue, Nov 16 2021, Taylor Blau wrote:
> >> At the end of this series we expose a config variable to have
> >> usage/die/warning emit line numbers. I.e. going from:
> >>
> >>     $ git -c core.usageAddSource=false -c core.x=y config --get --bool core.x
> >>     fatal: bad boolean config value 'y' for 'core.x'
> >>
> >> To:
> >>
> >>     $ git -c core.usageAddSource=false -c core.x=y config --get --bool core.x
> >>     fatal: config.c:1241: bad boolean config value 'y' for 'core.x'
> >
> > Just picking on this output change in particular. I agree that this is
> > easier for folks hacking on Git to trace down errors. But I'm not sure
> > that I could say then same about users, who will likely treat this extra
> > output as noise.
> >
> > Now we may find it helpful if they include it in a bug report, but I
> > feel reasonably comfortable saying that the value there is pretty
> > marginal. I don't find it all that problematic to grep for a specific
> > error string, and usually find myself in the right place.
>
> I wouldn't suggest exposing this to users, except perhaps as part of
> some "how to submit a bugreport" instructions. It's thoroughly optional.
>
> I thought it was easy enough to do with the preceding steps since all
> the data is there, and would help my workflow a lot.
>
> If you've got the file/line number like that you can make it clickable
> in your terminal/compile mode, e.g. Emacs's M-x compile. Saves time over
> having to grep manually select the string, grep for it etc.
>
> Anyway, I can certainly live with peeling this patch off the end and
> just stopping at the trace2 data for now, if you/others feel strongly
> about it.

I don't feel strongly, and I was just noting that it seemed like users
would treat this extra information more often as noise than anything
else.

When you talk about making it optional, do you mean through
configuration / an environment variable, or by including / not including
the patch? In other words, the latter seems much more like us making a
decision on whether or not to include line numbers rather than
presenting a new option to users, though I may be misunderstanding.

> As noted in 02/21 we're hard depending on this particular C99 feature
> already fon a few releases now, the only change on that front in this
> series is to stop committing to maintaining the non-C99 codepaths.

> We've already had hard dependencies on various bits of C99 for years now
> without any trouble, and I wouldn't expect any problems on this front
> either.

Interesting; so this and others are likely part of MSVC's kind-of
support for C99 features? In other words, that MSVC supports some
features from C99 (and we are depending on a subset of those) but not
all features so that it could reasonably be called a spec-compliant
compiler for the C99 standard? If so, makes sense.

Thanks,
Taylor