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





On 15/07/17 21:11, René Scharfe wrote:
> 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.
> 
> Signed-off-by: Rene Scharfe <l.s.r@xxxxxx>
> ---
>  builtin/ls-files.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> 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)

My patch looked like:

-       if (!prefix)
+       if (!prefix || !istate->cache || istate->cache_nr == 0)

... which is probably a bit 'belt-n-braces'. ;-)

ATB,
Ramsay Jones