[GitHub] [tvm] comaniac commented on a change in pull request #7175: [AutoTVM-FIX] avoid unexpected value(1) of search space when get length for uninitiated search space

[GitBox <gi...@apache.org>]

comaniac commented on a change in pull request #7175:
URL: https://github.com/apache/tvm/pull/7175#discussion_r549814017



##########
File path: python/tvm/autotvm/task/space.py
##########
@@ -836,7 +836,7 @@ def _add_new_transform(self, space_class, name, axes, policy, **kwargs):
         return [Axis(None, i) for i in range(space_class.get_num_output(axes, policy, **kwargs))]
 
     def __len__(self):
-        if self._length is None:
+        if self._length is None and len(self.space_map.values()) != 0:
             self._length = int(np.prod([len(x) for x in self.space_map.values()]))
         return self._length

Review comment:
       I found that this change is incorrect. `__len__` has to return an integer, but in this case it will return `None`. 
   
   ```suggestion
           if not self.space_map:
               return 0
           if self._length is None:
               self._length = int(np.prod([len(x) for x in self.space_map.values()]))
           return self._length
   ```




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