[BEAM-12465] Fix handling of nested typing.Generic type hints in Py3.7+

• Type: Improvement
• Status: Resolved
• Priority: P2
• Resolution: Fixed
• Fix Version/s: 2.32.0
• Component/s: sdk-py-core
• Assignee: Udi Meiri
• Reporter: Udi Meiri
• Created: 09/Jun/21 01:30
• Updated: 09/Jun/21 22:25
• Resolved: 09/Jun/21 22:25

Description

When Beam attempts to convert a type hint like `typing.Tuple[PCollection[int], PCollection[int]]` it will fail in Python 3.7+ with something like:

TypeError: Parameter to List hint must be a non-sequence, a type, or a TypeConstraint. PCollection[int] is an instance of _GenericAlias.

Issue Links

• links to: GitHub Pull Request #14975