Re: [PATCH] convert: fix handling of dashless UTF prefix in validate_encoding()

[Junio C Hamano <gitster@pobox.com>]

René Scharfe <l.s.r@web.de> writes:

> Strip "UTF" and an optional dash from the start of 'upper' without
> passing a NULL pointer to skip_prefix() in the second call, as it cannot
> handle that.

Did the original meant to say "skip UTF- from the beginning of upper
and store it to stripped, or if that cannot be done, skip UTF from
the beginning of upper and store it to stripped", but made the
second one scan the stripped instead of upper by mistake?

Changing it to "skip UTF from upper and store it to stripped, and if
the resulting stripped begins with dash, advance stripped to skip
that too" is certainly a right fix.  Fixing the second one to scan
upper would also make the result correct, but there is no point
scanning the same thing twice to skip the same leading "UTF"
substring.

Thanks.

>
> Signed-off-by: René Scharfe <l.s.r@web.de>
> ---
>  convert.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/convert.c b/convert.c
> index deb6f71b2d..25ac525d5f 100644
> --- a/convert.c
> +++ b/convert.c
> @@ -290,8 +290,8 @@ static int validate_encoding(const char *path, const char *enc,
>  			const char *stripped = NULL;
>  			char *upper = xstrdup_toupper(enc);
>  			upper[strlen(upper)-2] = '\0';
> -			if (!skip_prefix(upper, "UTF-", &stripped))
> -				skip_prefix(stripped, "UTF", &stripped);
> +			if (skip_prefix(upper, "UTF", &stripped))
> +				skip_prefix(stripped, "-", &stripped);
>  			advise(advise_msg, path, stripped);
>  			free(upper);
>  			if (die_on_error)
> @@ -310,8 +310,8 @@ static int validate_encoding(const char *path, const char *enc,
>  				"working-tree-encoding.");
>  			const char *stripped = NULL;
>  			char *upper = xstrdup_toupper(enc);
> -			if (!skip_prefix(upper, "UTF-", &stripped))
> -				skip_prefix(stripped, "UTF", &stripped);
> +			if (skip_prefix(upper, "UTF", &stripped))
> +				skip_prefix(stripped, "-", &stripped);
>  			advise(advise_msg, path, stripped, stripped);
>  			free(upper);
>  			if (die_on_error)
> --
> 2.23.0