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From: Taylor Blau <me@ttaylorr.com>
To: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Cc: git@vger.kernel.org, Junio C Hamano <gitster@pobox.com>,
	Jeff King <peff@peff.net>,
	Jeff Hostetler <jeffhost@microsoft.com>,
	Elijah Newren <newren@gmail.com>,
	Jonathan Tan <jonathantanmy@google.com>,
	Johannes Schindelin <Johannes.Schindelin@gmx.de>
Subject: Re: [RFC PATCH 00/21] C99: show meaningful <file>:<line> in trace2 via macros
Date: Tue, 16 Nov 2021 13:43:59 -0500	[thread overview]
Message-ID: <YZP771pJl30ujluT@nand.local> (raw)
In-Reply-To: <RFC-cover-00.21-00000000000-20211115T220831Z-avarab@gmail.com>

On Mon, Nov 15, 2021 at 11:18:10PM +0100, Ævar Arnfjörð Bjarmason wrote:
> Since everyone's getting in on the C99 fun.
>
> Well, $subject and a bit more. This RFC series has bits and pieces
> from thing I've submitted before. I'd proposed to make variadic macros
> a hard dependency before in [1] because I wanted to get to the goal in
> $subject, perhaps the whole thing will be more convincing.
>
> This also includes the die_message() in a recent series of mine[2]
> that I abandoned.
>
> 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 find that to make tracing down errors in the test suite, and 21/21
> has a GIT_TEST_* mode to turn it on there (which fails a lot now, but
> I'm hoping I'll eventually get passing).
>
> But most importantly we've now got meaningful file/line numbers in
> trace2 error events. I.e. from all of them being some line in usage.c:
>
>     $ GIT_TRACE2_EVENT=/dev/stdout ~/g/git/git -c core.usageAddSource=false -c core.x=y config --get --bool core.x 2>&1 2>/dev/null|grep error | jq -r .
>     {
>       "event": "error",
>       "sid": "20211115T221343.534151Z-Hc2f5b994-P003f3980",
>       "thread": "main",
>       "time": "2021-11-15T22:13:43.537981Z",
>       "file": "usage.c",
>       "line": 65,
>       "msg": "bad boolean config value 'y' for 'core.x'",
>       "fmt": "bad boolean config value '%s' for '%s'"
>     }
>
> To:
>
>     $ GIT_TRACE2_EVENT=/dev/stdout ~/g/git/git -c core.usageAddSource=false -c core.x=y config --get --bool core.x 2>&1 2>/dev/null|grep error | jq -r .
>     {
>       "event": "error",
>       "sid": "20211115T221357.083824Z-Hc2f5b994-P003f4a82",
>       "thread": "main",
>       "time": "2021-11-15T22:13:57.087596Z",
>       "file": "config.c",
>       "line": 1241,
>       "msg": "bad boolean config value 'y' for 'core.x'",
>       "fmt": "bad boolean config value '%s' for '%s'"
>     }

Neat. This is a use-case that has all of the value without putting it in
front of users all of the time. I like it.

> This is "RFC" mainly because there's a CI failure in 0061.2 with this,
> I still can't figure out what that's about (or if it's some fluke
> unrelated to this topic), but that has to be investigated.

Hmm. Putting the CI failures aside for a second, wouldn't we want to
hold off on something like this until we have flown the C99 weather
balloon for a while? If we suddenly start introducing C99-isms into the
code while brian's patch is still young, then we can suddenly no longer
say, "oh, just drop this #if because there are no other C99-specific
uses here", and instead compilers that don't support the newer standard
are out of luck.

That may have been already communicated elsewhere in this message and/or
throughout your patch series, so if I missed it, I apologize. Just
felt that it was worth stating the obvious before we go too far down the
wrong path.

Thanks,
Taylor

  parent reply	other threads:[~2021-11-16 18:44 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-15 22:18 [RFC PATCH 00/21] C99: show meaningful <file>:<line> in trace2 via macros Ævar Arnfjörð Bjarmason
2021-11-15 22:18 ` [RFC PATCH 01/21] git-compat-util.h: clarify GCC v.s. C99-specific in comment Ævar Arnfjörð Bjarmason
2021-11-15 22:18 ` [RFC PATCH 02/21] C99 support: hard-depend on C99 variadic macros Ævar Arnfjörð Bjarmason
2021-11-15 22:18 ` [RFC PATCH 03/21] usage.c: add a die_message() routine Ævar Arnfjörð Bjarmason
2021-11-15 22:18 ` [RFC PATCH 04/21] usage.c API users: use die_message() where appropriate Ævar Arnfjörð Bjarmason
2021-11-15 22:18 ` [RFC PATCH 05/21] usage.c + gc: add and use a die_message_errno() Ævar Arnfjörð Bjarmason
2021-11-15 22:18 ` [RFC PATCH 06/21] config API: don't use vreportf(), make it static in usage.c Ævar Arnfjörð Bjarmason
2021-11-15 22:18 ` [RFC PATCH 07/21] common-main.c: call exit(), don't return Ævar Arnfjörð Bjarmason
2021-11-15 22:18 ` [RFC PATCH 08/21] usage.c: add a non-fatal bug() function to go with BUG() Ævar Arnfjörð Bjarmason
2021-11-15 22:18 ` [RFC PATCH 09/21] parse-options.[ch] API: use bug() to improve error output Ævar Arnfjörð Bjarmason
2021-11-15 22:18 ` [RFC PATCH 10/21] receive-pack: use bug() and BUG_if_bug() Ævar Arnfjörð Bjarmason
2021-11-15 22:18 ` [RFC PATCH 11/21] cache-tree.c: " Ævar Arnfjörð Bjarmason
2021-11-15 22:18 ` [RFC PATCH 12/21] pack-objects: use BUG(...) not die("BUG: ...") Ævar Arnfjörð Bjarmason
2021-11-15 22:18 ` [RFC PATCH 13/21] strbuf.h: " Ævar Arnfjörð Bjarmason
2021-11-15 22:18 ` [RFC PATCH 14/21] usage API: create a new usage.h, move API docs there Ævar Arnfjörð Bjarmason
2021-11-15 22:18 ` [RFC PATCH 15/21] usage.[ch] API users: use report_fn, not hardcoded prototype Ævar Arnfjörð Bjarmason
2021-11-15 22:18 ` [RFC PATCH 16/21] usage.[ch] API: rename "warn" vars functions to "warning" Ævar Arnfjörð Bjarmason
2021-11-15 22:18 ` [RFC PATCH 17/21] usage.c: move usage routines around Ævar Arnfjörð Bjarmason
2021-11-15 22:18 ` [RFC PATCH 18/21] usage.c: move rename variables in " Ævar Arnfjörð Bjarmason
2021-11-15 22:18 ` [RFC PATCH 19/21] usage API: use C99 macros for {usage,usagef,die,error,warning,die}*() Ævar Arnfjörð Bjarmason
2021-12-27 19:32   ` Jeff Hostetler
2021-12-27 23:01     ` Ævar Arnfjörð Bjarmason
2021-12-28 16:32       ` Jeff Hostetler
2021-12-28 18:51         ` Elijah Newren
2021-12-28 23:48           ` Ævar Arnfjörð Bjarmason
2021-12-29  2:15             ` Elijah Newren
2021-12-28 23:42         ` Ævar Arnfjörð Bjarmason
2021-12-29 16:13         ` Jeff Hostetler
2021-11-15 22:18 ` [RFC PATCH 20/21] usage API: make the "{usage,fatal,error,warning,BUG}: " translatable Ævar Arnfjörð Bjarmason
2021-11-15 22:18 ` [RFC PATCH 21/21] usage API: add "core.usageAddSource" config to add <file>:<line> Ævar Arnfjörð Bjarmason
2021-11-16 18:43 ` Taylor Blau [this message]
2021-11-16 18:58   ` [RFC PATCH 00/21] C99: show meaningful <file>:<line> in trace2 via macros Ævar Arnfjörð Bjarmason
2021-11-16 19:36     ` Taylor Blau
2021-11-16 20:16       ` Ævar Arnfjörð Bjarmason

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