[BEAM-9755] infer_return_type does not infer as expected in Python 3.8

• Type: Sub-task
• Status: Resolved
• Priority: P2
• Resolution: Fixed
• Fix Version/s: Not applicable
• Component/s: sdk-py-core
• Assignee: yoshiki obata
• Reporter: yoshiki obata
• Created: 14/Apr/20 13:21
• Updated: 16/May/20 14:08
• Resolved: 27/Apr/20 14:48

Description

apache_beam.typehints.trivial_inference.infer_return_type does not return type as expected in Python 3.8.
And this cause testDictComprehensionSimple (apache_beam.typehints.trivial_inference_test.TrivialInferenceTest) FAIL.

• Python 3.7.7

   >> from apache_beam.typehints.trivial_inference import infer_return_type
   >> infer_return_type(lambda _list: {'a': 1 for _ in _list}, [], debug=False, depth=5)
   Dict[str, int]

• Python 3.8.2

   >> from apache_beam.typehints.trivial_inference import infer_return_type
   >> infer_return_type(lambda _list: {'a': 1 for _ in _list}, [], debug=False, depth=5)
   Dict[int, str]

   

CPython bytecode changes[1] may affect.

 [1] https://docs.python.org/3/whatsnew/3.8.html