From: Kristoffer Haugsbakk <kristofferhaugsbakk@fastmail.com>
Date: Mon, 04 May 2026 08:55:16 GMT
Subject: Re: [PATCH] name-rev: fix an 'may be used uninitialized' error
Message-ID: <592c01fd-1e1b-4850-adf1-77fffdf71321@app.fastmail.com>
In-Reply-To: <xmqqv7d4ou3m.fsf@gitster.g>

Hi Junio

On Mon, May 4, 2026, at 03:13, Junio C Hamano wrote:
> Ramsay Jones <ramsay@ramsayjones.plus.com> writes:
>
>> Today's seen branch fails to build (with DEVELOPER=1), like so:
>>
>>       CC builtin/name-rev.o
>>   builtin/name-rev.c: In function ‘cmd_format_rev’:
>>   builtin/name-rev.c:885:28: error: ‘commit’ may be used uninitialized [-Werror=maybe-uninitialized]
>>     885 |                         if (!commit) {
>>         |                            ^
>>   builtin/name-rev.c:867:40: note: ‘commit’ was declared here
>>     867 |                         struct commit *commit;
>>         |                                        ^~~~~~
>>   cc1: all warnings being treated as errors
>>   make: *** [Makefile:2932: builtin/name-rev.o] Error 1
>> ...
>> diff --git a/builtin/name-rev.c b/builtin/name-rev.c
>> index b941e93834..5b7f7a00e5 100644
>> --- a/builtin/name-rev.c
>> +++ b/builtin/name-rev.c
>> @@ -882,6 +882,8 @@ int cmd_format_rev(int argc,
>>  			peeled = deref_tag(the_repository, object, scratch_buf.buf, 0);
>>  			if (peeled && peeled->type == OBJ_COMMIT)
>>  				commit = (struct commit *)peeled;
>> +			else
>> +				commit = NULL;
>>  			if (!commit) {
>>  				fprintf(stderr, "Could not get commit for %s. Skipping.\n",
>>  					*argv);
>
> Why not
>
> 			if (peeled && peeled->type == OBJ_COMMIT) {
> 				commit = (struct commit *)peeled;
> 			} else {
> 				fprintf(stderr, "... skipping ...");
> 				continue;
> 			}
>
> 			get_format_rev(commit, &format_pp, &scratch);
>
> or even
>
> 			if (!peeled || peeled->type != OBJ_COMMIT) {
> 				fprintf(stderr, "... skipping ...");
> 				continue;
> 			}
>
> 			get_format_rev((struct commit *)peeled->type,
> 					&format_pp, &scratch);
>
> and dropping the variable "struct commit *commit" altogether?

I see that you added this as one of two “SQUASH???” commits on your
kh/name-rev-custom-format branch. I will squash both of them in for the
next round.

Thanks to both of you.