Must not modify the_index.cache as it may be passed to realloc at some point.

The index cache is not static, growing as new entries are added. If
entries are added after prune_cache is called, cache will no longer
point at the base of the allocation, and realloc will not be happy.

I verified that this was the only place in the current source which
modified any index_state.cache elements aside from the alloc/realloc
calls in read-cache by changing the type of the element to 'struct
cache_entry ** const cache' and recompiling.

A more efficient patch would create a separate 'cache_base' value to
track the allocation and then fix things up when reallocation was
necessary, instead of the brute-force memmove used here.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin-ls-files.c b/builtin-ls-files.c
index 6c1db86e8056285cb25359d55f5ebf9dd0e6f489..171d449048d304b043ed33776fab4bf95434e30a 100644 (file)
--- a/builtin-ls-files.c
+++ b/builtin-ls-files.c
@@ -280,7 +280,8 @@ static void prune_cache(const char *prefix)
 
        if (pos < 0)
                pos = -pos-1;
-       active_cache += pos;
+       memmove(active_cache, active_cache + pos,
+               (active_nr - pos) * sizeof(struct cache_entry *));
        active_nr -= pos;
        first = 0;
        last = active_nr;