Re: [PATCH 2/4] format-patch: fix a bug in option exclusivity and add a test to t4014

[Dragan Simic <dsimic@manjaro.org>]

Hello Patrick,

On 2024-04-17 08:27, Patrick Steinhardt wrote:
> On Wed, Apr 17, 2024 at 05:32:42AM +0200, Dragan Simic wrote:
>> Fix a bug that allows --rfc and -k options to be specified together 
>> when
>> executing "git format-patch".  This bug was introduced back in the 
>> commit
>> e0d7db7423a9 ("format-patch: --rfc honors what --subject-prefix 
>> sets"),
>> about eight months ago, but it has remained undetected so far, 
>> presumably
>> because of no associated test coverage.
>> 
>> Add a new test to the t4014 that covers the mutual exclusivity of the 
>> --rfc
>> and -k command-line options for "git format-patch", for future 
>> coverage.
>> 
>> Signed-off-by: Dragan Simic <dsimic@manjaro.org>
>> ---
>>  builtin/log.c           | 5 ++++-
>>  t/t4014-format-patch.sh | 4 ++++
>>  2 files changed, 8 insertions(+), 1 deletion(-)
>> 
>> diff --git a/builtin/log.c b/builtin/log.c
>> index c0a8bb95e983..e5a238f1cf2c 100644
>> --- a/builtin/log.c
>> +++ b/builtin/log.c
>> @@ -2050,8 +2050,11 @@ int cmd_format_patch(int argc, const char 
>> **argv, const char *prefix)
>>  	if (cover_from_description_arg)
>>  		cover_from_description_mode = 
>> parse_cover_from_description(cover_from_description_arg);
>> 
>> -	if (rfc)
>> +	/* Also mark the subject prefix as modified, for later checks */
>> +	if (rfc) {
>>  		strbuf_insertstr(&sprefix, 0, "RFC ");
>> +		subject_prefix = 1;
>> +	}
> 
> As an alternative fix, can we drop `subject_prefix` and replace it with
> `sprefix.len` instead? It seems to merely be a proxy value for that
> anyway, and if we didn't have that variable then the bug would not have
> been possible to begin with.

Thanks for your feedback!

I'll think about it, and I'll come back a bit later with an update.

>>  	if (reroll_count) {
>>  		strbuf_addf(&sprefix, " v%s", reroll_count);
>> diff --git a/t/t4014-format-patch.sh b/t/t4014-format-patch.sh
>> index e37a1411ee24..e22c4ac34e6e 100755
>> --- a/t/t4014-format-patch.sh
>> +++ b/t/t4014-format-patch.sh
>> @@ -1397,6 +1397,10 @@ test_expect_success '--rfc is argument order 
>> independent' '
>>  	test_cmp expect actual
>>  '
>> 
>> +test_expect_success '--rfc and -k cannot be used together' '
>> +	test_must_fail git format-patch -1 --stdout --rfc -k >patch
>> +'
>> +
>>  test_expect_success '--from=ident notices bogus ident' '
>>  	test_must_fail git format-patch -1 --stdout --from=foo >patch
>>  '
>>