query: is_*_namespace: input must be hashable? #421

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1. ev-br commented on Apr 19, 2026

   

   ev-br

   on Apr 19, 2026

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   Is this a problem?

   Modules are hashable, unless under torch.compile IIUC, so I suppose it is related to #411, which you fixed in gh-413.

   Here's a quick poking around session with torch.compile below. It looks like Dynamo special-cases @lru_cache so that it compiles at least, but there's some rough edge with resource management (cf the printed backtrace on exit). No idea how severe it is though, so probably some more investigation is in order.

   In [1]: from array_api_compat import is_numpy_namespace, is_torch_namespace, is_jax_namespace
   
   In [2]: def foo(x, xp): 
      ...:     x = x*x
      ...:     return x, is_torch_namespace(xp), is_numpy_namespace(xp)
      ...: 
   
   In [4]: import torch
   
   In [5]: bar = torch.compile(fullgraph=True)(foo)
   
   In [6]: bar(torch.arange(3), torch)
   Out[6]: (tensor([0, 1, 4]), True, False)
   
   In [7]: exit()
   Exception ignored in: <function ExactWeakKeyDictionary.__setitem__.<locals>.<lambda> at 0x7fde1cd06340>
   Traceback (most recent call last):
     File "/home/br/miniforge3/envs/scipy-dev/lib/python3.12/site-packages/torch/_dynamo/utils.py", line 908, in <lambda>
       self.refs[idx] = weakref.ref(key, lambda ref: self._remove_id(idx))
                                                     ^^^^^^^^^^^^^^^^^^^^
     File "/home/br/miniforge3/envs/scipy-dev/lib/python3.12/site-packages/torch/_dynamo/utils.py", line 1928, in _remove_id
       hook()
     File "/home/br/miniforge3/envs/scipy-dev/lib/python3.12/site-packages/torch/_dynamo/utils.py", line 1912, in __call__
       del self.scope[self.name]
           ~~~~~~~~~~^^^^^^^^^^^
   KeyError: '__builtins_dict___0'
   

   ---

   Two more comments/questions:

   • we could use module names for cache keys, similar to ENH: array_namespace: support torch.compile #413; cf Raymond Hettinger's answer at
     https://stackoverflow.com/questions/30730983/make-lru-cache-ignore-some-of-the-function-arguments which suggests an auxilliary function. Will probably want to see if this
     • helps with the KeyError above;
     • has a measurable perf impact; IIRC @crusaderky added caching to improve perf on some workloads in ENH: cache helper functions #308, what were they?
   • not all is_*_namespace functions are decorated with @lru_cache; e.g. is_jax_namespace is not. Was this deliberate?
2. lucascolley commented on Apr 19, 2026

   

   lucascolley

   on Apr 19, 2026

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   Modules are hashable

   ah, okay, this might be a bug in the type-checker I was using, sorry. DetachHead/basedpyright#1779