Re: [PATCH 2/2] diff-no-index: release prefixed filenames

["René Scharfe" <l.s.r@web.de>]

Am 07.09.22 um 12:03 schrieb Johannes Schindelin:
> Hi René,
>
> On Tue, 6 Sep 2022, René Scharfe wrote:
>
>> diff --git a/diff-no-index.c b/diff-no-index.c
>> index a3683d8a04..35809f26d7 100644
>> --- a/diff-no-index.c
>> +++ b/diff-no-index.c
>> @@ -245,6 +245,7 @@ int diff_no_index(struct rev_info *revs,
>>  	int i, no_index;
>>  	int ret = 1;
>>  	const char *paths[2];
>> +	char *to_free[2] = { 0 };
>>  	struct strbuf replacement = STRBUF_INIT;
>>  	const char *prefix = revs->prefix;
>>  	struct option no_index_options[] = {
>> @@ -274,7 +275,7 @@ int diff_no_index(struct rev_info *revs,
>>  			 */
>>  			p = file_from_standard_input;
>>  		else if (prefix)
>> -			p = prefix_filename(prefix, p);
>> +			p = to_free[i] = prefix_filename(prefix, p);
>>  		paths[i] = p;
>>  	}
>>
>> @@ -308,6 +309,8 @@ int diff_no_index(struct rev_info *revs,
>>  	ret = diff_result_code(&revs->diffopt, 0);
>>
>>  out:
>> +	for (i = 0; i < 2; i++)
>> +		free(to_free[i]);
>
> Heh. That's long-hand for
>
> 	free(to_free[0]);
> 	free(to_free[1]);

Had that before, but it's repetitive and more importantly this loop
matches the first one.

> If you do want to have that loop, please replace the hard-coded 2 by
> `ARRAY_SIZE(to_free)`.

The two is hard-coded in other places explicitly as well and implied in
fixup_paths().  The root cause is not any array size but the design
decision to require exactly two things to compare.  A reader would need
to know that.  We could sure use ARRAY_SIZE(paths) in the declaration
of to_free and ARRAY_SIZE(to_free) in the loop to at least not add more
instances of that magic number and make the code understandable without
seeing the bigger picture.

> Otherwise, both patches look fine to me.
>
> Thanks!
> Dscho
>
>>  	strbuf_release(&replacement);
>>  	return ret;
>>  }
>> --
>> 2.37.2
>>