Re: [PATCH] Fix deletion of last character in levenshtein distance

From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Nov 19, 2008, 00:53 UTC
Message-ID: <alpine.DEB.1.00.0811190151000.30769@pacific.mpi-cbg.de>
In-Reply-To: <20081118185326.12721.71576.stgit@arrakis.enst.fr>

Hi,

On Tue, 18 Nov 2008, Samuel Tardieu wrote:

Show 10 quoted lines

> diff --git a/levenshtein.c b/levenshtein.c
> index db52f2c..98fea72 100644
> --- a/levenshtein.c
> +++ b/levenshtein.c
> @@ -25,7 +25,7 @@ int levenshtein(const char *string1, const char *string2,
>  					row2[j + 1] > row0[j - 1] + w)
>  				row2[j + 1] = row0[j - 1] + w;
>  			/* deletion */
> -			if (j + 1 < len2 && row2[j + 1] > row1[j + 1] + d)
> +			if (row2[j + 1] > row1[j + 1] + d)

I do not understand: does row2 have more entries than len2? In any case, you will _have_ to guard against accessing elements outside the reserved memory.

You'll have to be more convincing to make me agree that this is a good change, and I am pretty certain that other people are less familiar with that particular part of Git's source code than me.

Ciao, Dscho