From: René Scharfe <l.s.r@web.de>
Date: Sun, 16 Jul 2017 11:06:45 GMT
Subject: Re: [PATCH] ls-files: don't try to prune an empty index
Message-ID: <e91c204d-0bcb-9614-b62d-cd87c03b92e1@web.de>
In-Reply-To: <20170716104114.7tfcuilsy3ab74n6@sigill.intra.peff.net>

Am 16.07.2017 um 12:41 schrieb Jeff King:
> On Sat, Jul 15, 2017 at 10:11:20PM +0200, 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.
> 
> Makes sense. We could use MOVE_ARRAY() here, but this is a sensible
> short-circuit to the whole function.
> 
> Looks like a good solution.
> 
>> 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?

I didn't, but perhaps I messed up the order of patches?  MOVE_ARRAY
patch 2 touches the same file, but I wouldn't expect the two changes to
conflict.  So not sure what's going on.

René