[ZOOKEEPER-3314] Document the possibility of MultiCallback receiving a null pointer

• Type: Improvement
• Status: Resolved
• Priority: Trivial
• Resolution: Fixed
• Affects Version/s: 3.4.7, 3.4.8, 3.4.9, 3.4.10, 3.5.0, 3.5.1, 3.5.2, 3.5.3, 3.4.11, 3.5.4, 3.4.12, 3.4.13
• Fix Version/s: 3.6.0
• Labels: pull-request-available
• Flags: Patch
• Assignee: Steven McDonald
• Reporter: Steven McDonald
• Created: 15/Mar/19 11:38
• Updated: 10/Apr/19 00:27
• Resolved: 09/Apr/19 12:37

Description

A MultiCallback can receive a null pointer on failure, rather than a list of org.apache.zookeeper.OpResult.ErrorResult as documented. This is evident from the implementation.

This causes NullPointerExceptions in Kafka 2.1.x (see KAFKA-7898). Kafka 2.0.x does not use the async multi interface, and Kafka 2.2.x handles the null pointer case.

However, this is enough of a hazard that it should be documented. I have a patch for that which I will try to attach in a moment (JIRA won't allow me to attach it now for some reason).

Issue Links

• links to: GitHub Pull Request #884