Re: [PATCH 1/2] git-compat-util: introduce MEMZERO_ARRAY() macro

From: René Scharfe <l.s.r@web.de>
Date: Dec 12, 2025, 13:02 UTC
Message-ID: <f02b628f-b9d7-4436-88ee-3255e02cb0f3@web.de>
In-Reply-To: <xmqqtsxxg0z4.fsf@gitster.g>

On 12/11/25 4:18 AM, Junio C Hamano wrote:

Show 13 quoted lines

> Toon Claes <toon@iotcl.com> writes:
> 
>> +@@
>> +- memset(ptr, \( 0x0 \| 0 \), n * \( sizeof(T)
>> +-                                 \| sizeof(*ptr)
>> +-                                 \) )
>> ++ MEMZERO_ARRAY(ptr, n)
> 
> Shouldn't we be also catching
> 
> 	memset(array, '\0', sizeof(array[0]) * ARRAY_SIZE(array));
> 
> in addition to "0" and "0x0"?

Good idea to match "sizeof(ptr[...])", even though we currently don't have matching code.

Good idea also to match "'\0'". There's code with that pattern in compat/regex/.

You can drop "0x0", though, "0" matches it already (at least for me, I have "spatch version 1.3-dirty compiled with OCaml version 5.1.1" from Homebrew).

If you put parentheses around "n" in the pre-image then Coccinelle will remove them if present and still match code without them. They are no longer needed without the multiplication. Their removal would improve the result for ewah/bitmap.c.

René