Merge branch 'ds/sparse-updates-oob-access-fix'

The code to skip unmerged paths in the index when sparse checkout
is in use would have made out-of-bound access of the in-core index
when the last path was unmerged, which has been corrected.

* ds/sparse-updates-oob-access-fix:
  unpack-trees: avoid array out-of-bounds error
diff --git a/unpack-trees.c b/unpack-trees.c
index 1fe3764..02048df 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -562,11 +562,11 @@ static int warn_conflicted_path(struct index_state *istate,
 
 	add_rejected_path(o, WARNING_SPARSE_UNMERGED_FILE, conflicting_path);
 
-	/* Find out how many higher stage entries at same path */
-	while (++count < istate->cache_nr &&
-	       !strcmp(conflicting_path,
-		       istate->cache[i+count]->name))
-		/* do nothing */;
+	/* Find out how many higher stage entries are at same path */
+	while ((++count) + i < istate->cache_nr &&
+	       !strcmp(conflicting_path, istate->cache[count + i]->name))
+		; /* do nothing */
+
 	return count;
 }