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

From: René Scharfe <l.s.r@web.de>
Date: Jul 15, 2017, 20:11 UTC
Message-ID: <bbc51fb0-70ce-3b02-274b-31b5dc035e29@web.de>

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@web.de>
---
  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)

-- 
2.13.3