Re: [PATCH v9 9/9] cocci: allow padding with `strbuf_addf()`

From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Jan 7, 2022, 13:03 UTC
Message-ID: <nycvar.QRO.7.76.6.2201071401240.339@tvgsbejvaqbjf.bet>
In-Reply-To: <8dafb2b3779715aa277eb825a94af87b72f3e093.1641440700.git.dyroneteng@gmail.com>

Hi Teng,

On Thu, 6 Jan 2022, Teng Long wrote:

Show 10 quoted lines

> A convenient way to pad strings is to use something like
> `strbuf_addf(&buf, "%20s", "Hello, world!")`.
>
> However, the Coccinelle rule that forbids a format `"%s"` with a
> constant string argument cast too wide a net, and also forbade such
> padding.
>
> The original rule was introduced by commit:
>
>     https://github.com/git/git/commit/28c23cd4c3902449aff72cb9a4a703220be0d6ac

Doing this in 9/9 is too late, by this time you already introduced the code site that requires this workaround.

At the same time, I wonder why you want to defend spinning up the full-blown `printf()` machinery just to pad text that you can easily pad yourself. It sounds like a lot of trouble to me to introduce this patch and then use an uncommon method to pad a fixed string at runtime. Too much trouble for my liking.

Ciao, Dscho

Show 24 quoted lines

>
> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> Signed-off-by: Teng Long <dyroneteng@gmail.com>
> ---
>  contrib/coccinelle/strbuf.cocci | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/contrib/coccinelle/strbuf.cocci b/contrib/coccinelle/strbuf.cocci
> index d9ada69b43..2d6e0f58fc 100644
> --- a/contrib/coccinelle/strbuf.cocci
> +++ b/contrib/coccinelle/strbuf.cocci
> @@ -44,7 +44,7 @@ struct strbuf *SBP;
>
>  @@
>  expression E1, E2;
> -format F =~ "s";
> +format F =~ "^s$";
>  @@
>  - strbuf_addf(E1, "%@F@", E2);
>  + strbuf_addstr(E1, E2);
> --
> 2.33.0.rc1.1794.g2ae0a9cb82
>
>