Re: [PATCH] builtin/gc.c: fix -Wdeclaration-after-statement

[Johannes Schindelin <Johannes.Schindelin@gmx.de>]

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Hi Ævar,

On Tue, 15 Nov 2022, Johannes Schindelin wrote:

> On Tue, 15 Nov 2022, Ævar Arnfjörð Bjarmason wrote:
>
> > In 1f80129d61b (maintenance: add option to register in a specific
> > config, 2022-11-09) code was added which triggers a
> > "-Wdeclaration-after-statement" warning, which is on by default with
> > DEVELOPER=1.
> >
> > Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> > ---
> >
> > This landed in the latest "next" push-out, causing e.g this CI
> > failure:
> > https://github.com/git/git/actions/runs/3467538041/jobs/5792504315
>
> I looked at the same thing all morning, and found that
> https://lore.kernel.org/git/20221111231910.26769-1-ronan@rjp.ie/
> _probably_ was designed to fix the same issue (and I think you agree that
> that patch should be used instead of yours because it is more complete in
> fixing left-over issues).
>
> However, try as I might, I did not find out yet why it does not apply
> cleanly over here (I got side-tracked into range-diff'ing patches
> downloaded from the archive, which is quite the challenge and not even fun
> because `range-diff` requires commits, not emails, so I side-tracked
> myself into teaching `range-diff` to accept mbox arguments).
>
> Maybe you can adjust that patch so it applies cleanly?

Seems that the v2 of "maintenance: improve error reporting for
unregister" [*1*] was _partially_ folded into v3 of "maintenance: add
option to register in a specific config": At least the config change that
talks about `--config-file` inste of `--config` _is_ part of v3, and one
reason that the former patch does not apply cleanly on top of the latter
patch. Which is a bit funny because the former patch was sent out two days
_after_ the latter patch.

And it looks as if there is one more thing that needs to be forward-ported
from that no-longer-applying patch: the initialization of the configset,
otherwise we're potentially trying to clear an uninitialized data
structure.

This is the patch I am currently testing (on top of Git for Windows'
`shears/seen` branch:
https://github.com/git-for-windows/git/commit/cd7b86d19f):

-- snip --
diff --git a/builtin/gc.c b/builtin/gc.c
index 635f12499d68..a3f63880dfba 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -1569,6 +1569,7 @@ static int maintenance_unregister(int argc, const char **argv, const char *prefi
 	int found = 0;
 	struct string_list_item *item;
 	const struct string_list *list;
+	struct config_set cs;

 	argc = parse_options(argc, argv, prefix, options,
 			     builtin_maintenance_unregister_usage, 0);
@@ -1576,9 +1577,8 @@ static int maintenance_unregister(int argc, const char **argv, const char *prefi
 		usage_with_options(builtin_maintenance_unregister_usage,
 				   options);

-	struct config_set cs;
+	git_configset_init(&cs);
 	if (config_file) {
-		git_configset_init(&cs);
 		git_configset_add_file(&cs, config_file);
 		list = git_configset_get_value_multi(&cs, key);
 	} else {
-- snap --

Ævar, can you please have a thorough look and see whether there is
anything else we were missing before advancing this to `next`?

Thanks,
Dscho

Footnote *1*: https://lore.kernel.org/git/20221111231910.26769-1-ronan@rjp.ie/
Footnote *2*: https://lore.kernel.org/git/20221109190708.22725-3-ronan@rjp.ie/