[FLINK-5713] Protect against NPE in WindowOperator window cleanup

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Duplicate
• Affects Version/s: 1.2.0
• Fix Version/s: 1.2.1
• Component/s: API / DataStream
• Assignee: Aljoscha Krettek
• Reporter: Aljoscha Krettek
• Created: 05/Feb/17 14:29
• Updated: 21/Mar/17 14:25
• Resolved: 21/Mar/17 14:25

Description

Some (misbehaved) WindowAssigners can cause windows to be dropped from the merging window set while a cleanup timer is still active. This will trigger a NullPointerException when that timer fires.

Issue Links

• links to: GitHub Pull Request #3535