Re: [PATCH] ls-files: don't try to prune an empty index

From: Jeff King <peff@peff.net>
Date: Jul 16, 2017, 10:41 UTC
Message-ID: <20170716104114.7tfcuilsy3ab74n6@sigill.intra.peff.net>
In-Reply-To: <bbc51fb0-70ce-3b02-274b-31b5dc035e29@web.de>

On Sat, Jul 15, 2017 at 10:11:20PM +0200, René Scharfe wrote:

Show 5 quoted lines

> Exit early when asked to prune an index that contains no
> entries to begin with.  This avoids pointer arithmetic on
> istate->cache, which is possibly NULL in that case.
> 
> Found with Clang's UBSan.

Makes sense. We could use MOVE_ARRAY() here, but this is a sensible short-circuit to the whole function.

Looks like a good solution.

Show 13 quoted lines

> diff --git a/builtin/ls-files.c b/builtin/ls-files.c
> index b8514a0029..adf572da68 100644
> --- a/builtin/ls-files.c
> +++ b/builtin/ls-files.c
> @@ -362,7 +362,7 @@ static void prune_index(struct index_state *istate,
>  	int pos;
>  	unsigned int first, last;
> 
> -	if (!prefix)
> +	if (!prefix || !istate->cache_nr)
>  		return;
>  	pos = index_name_pos(istate, prefix, prefixlen);
>  	if (pos < 0)

"git am" complained that this does not apply to its blobs. Did you hand-edit?

-Peff