compact_array: Fix ubsan error (#284)

Do not `memcpy` or `deallocate` if `old_capacity == 0`. `Array() == nullptr` in this case, so `memcpy` is UB. Fixes #283 .
google · Nov 28, 2022 · e15d00b · e15d00b
1 parent 254c136
commit e15d00b
Showing 1 changed file with 4 additions and 2 deletions.
diff --git a/src/s2/util/gtl/compact_array.h b/src/s2/util/gtl/compact_array.h
@@ -413,8 +413,10 @@ class compact_array_base {
     value_allocator_type allocator;
 
     T* new_ptr = allocator.allocate(capacity());
-    memcpy(new_ptr, Array(), old_capacity * sizeof(T));
-    allocator.deallocate(Array(), old_capacity);
+    if (old_capacity != 0) {
+      memcpy(new_ptr, Array(), old_capacity * sizeof(T));
+      allocator.deallocate(Array(), old_capacity);
+    }
 
     SetArray(new_ptr);
   }