Merge branch 'kl/attr-read-attr-fromindex-msan-workaround' into next

Code clarification to avoid an appearance of using an uninitialized
variable.

* kl/attr-read-attr-fromindex-msan-workaround:
  attr: fix msan issue in read_attr_from_index

attr.c

@@ -865,7 +865,8 @@ static struct attr_stack *read_attr_from_index(struct index_state *istate,
 		stack = read_attr_from_blob(istate, &istate->cache[sparse_dir_pos]->oid, relative_path, flags);
 	} else {
 		buf = read_blob_data_from_index(istate, path, &size);
-		stack = read_attr_from_buf(buf, size, path, flags);
+		if (buf)
+			stack = read_attr_from_buf(buf, size, path, flags);
 	}
 	return stack;
 }