Re: [PATCH] am: fix condition check on fseek

From: Kristoffer Haugsbakk <kristofferhaugsbakk@fastmail.com>
Date: Sep 21, 2024, 19:52 UTC
Message-ID: <7601dcef-e256-4e20-bbd4-75955e5a45d5@app.fastmail.com>
In-Reply-To: <20240921150855.31574-1-RuffaloLavoisier@gmail.com>

On Sat, Sep 21, 2024, at 17:08, Ruffalo Lavoisier wrote:

Show 22 quoted lines

> if fseek() is success, return value is 0
>
> Signed-off-by: Ruffalo Lavoisier <RuffaloLavoisier@gmail.com>
> ---
>  builtin/am.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/builtin/am.c b/builtin/am.c
> index d8875ad402..a7727fd4ea 100644
> --- a/builtin/am.c
> +++ b/builtin/am.c
> @@ -589,7 +589,7 @@ static int is_mail(FILE *fp)
>  	regex_t regex;
>  	int ret = 1;
>
> -	if (fseek(fp, 0L, SEEK_SET))
> +	if (!fseek(fp, 0L, SEEK_SET))
>  		die_errno(_("fseek failed"));
>
>  	if (regcomp(&regex, header_regex, REG_NOSUB | REG_EXTENDED))
> --
> 2.46.1

I don’t get this change? The function returns false on success. true if it fails (not zero). You want the program to die if it returns non-zero.

It’s hard to wrap my head around… “false must mean “no errors” ”

If the original code has a bug then I don’t see how git-am(1) could work considering it presumably always checks ‘is_mail’.

-- 
Kristoffer