curator CURATOR-609 - ModeledCache attempts to deserialize empty ZNodes on deletion, resulting in exceptions

On event type NODE_REMOVED, an additional check was added to ensure that the ZNode actually contains data before attempting to deserialize it into a model.

If no model is present for the ZNode, the accept callback is not called (as this is not a valid ModeledFramework object).

This is already accounted for with events NODE_ADDED/NODE_UPDATED, as there was already a check for null data in the node.

Note: Triggering this bug via a unit test is quite easy, however detecting it is difficult as the exception is thrown by a Curator sub-thread. Therefore I did not add a matching unit test (though ensured all existing unit tests pass).

Aug 05 '21 15:08 Ryan0751

This issue was targeted 5.2.1 I am postponing to 5.2.2, I am sorry

Mar 14 '22 08:03 eolivelli

@Ryan0751 Any interest to continue this ? I think you can construct a test with ModeledCacheListener.handleException. TestCachedModeledFramework should be the right place. I can take care of it in case you are not available. We are evaluating this and plan to conclude (merge or not) this before next release.

Apr 06 '23 15:04 kezhuw

I will take another look!

Apr 07 '23 11:04 Ryan0751

I have gone ahead and added a unit test for this.

Apr 08 '23 12:04 Ryan0751

Thanks for your contribution @Ryan0751! It reminds me of one of my PRs merged after two years in apache/flink 🤣

Apr 11 '23 14:04 tisonkun

Merging...

Thank you @Ryan0751!

Apr 12 '23 02:04 tisonkun