[BEAM-3510] Python Runner API serialization for CombinePerKey drops arguments to CombineFn

• Type: Bug
• Status: Resolved
• Priority: P2
• Resolution: Fixed
• Affects Version/s: 2.2.0
• Fix Version/s: 2.3.0
• Component/s: sdk-py-core
• Assignee: Robert Bradshaw
• Reporter: Charles Chen
• Created: 22/Jan/18 20:08
• Updated: 16/May/20 13:30
• Resolved: 23/Jan/18 00:12

Description

Currently, the Runner API serialization for CombinePerKey drops the args and kwargs that are passed at runtime to the CombineFn.  We should fix this issue so that the Runner API round-trip preserves semantics.