[BEAM-10517] DirectRunner multi step combine has questionable null / Map treatment

• Type: Bug
• Status: Resolved
• Priority: P1
• Resolution: Fixed
• Fix Version/s: 2.24.0
• Component/s: runner-direct
• Assignee: Kenneth Knowles
• Reporter: Kenneth Knowles
• Created: 16/Jul/20 20:55
• Updated: 20/Jul/20 17:59
• Resolved: 20/Jul/20 17:59

Description

When outputting accumulators in pre-combine, the direct runner iterates over a map of accumulators. However, since an accumulator can be null (such as in zetasketch) these accumulators will not be output.

Issue Links

• links to: GitHub Pull Request #12284