DecisionTables with collect hit policy overwite outputs

[edward-morgan]

Hi, and thanks for all your hard work on this project! I wanted to bring up a potential bug that our team has run into around Decision Tables with the collect hit policy.

Given a decision model like the following: edge-ordering.json

where decisionTable1 has a collect hit policy, the order that decisionTable1 and expression1 are connected to response dictates what is produced.

If decisionTable1 is connected first:

If expression1 is connected first:

This appears to be due to the overwriting strategy in merge_variables(), specifically if merging an array with an object. This problem seems somewhat similar to #90, but I wanted to bring it up separately since connecting nodes in a certain order will change what data are produced even though everything looks the same in the UI (and the internal graphs are structurally identical).

From reading the earlier discussion, I'm guessing the current strategy would be to fix this in the JDM with a Function node to coalesce the array:

/** @type {Handler} **/
export const handler = async (input) => {
  return {"collected": input};
};

Can this be fixed in the engine instead? Alternatively, I can put up a PR updating the README with a note mentioning this and the recommended workaround.

[ivanmiletic]

Hi, we are in process of releasing a new features that will solve your issue.

It will allow you to set output of nodes to some field or "path". Also it will allow us to do loops in certain nodes as well as passthrough data merge.

[stefan-gorules]

Hi, as this has been released I will move this to a discussion.

[jakeberg]

Was this fix added in 0.32.0 for the Node package?

[ivanmiletic]

Yes, you can scroll at the end of this page to check: https://docs.gorules.io/docs/loops#output-path

[edward-morgan]

That's great, thanks so much!

[stefan-gorules]

You are welcome! Forgot to mention here are the docs for your use case:
https://gorules.io/docs/user-manual/decision-modeling/data-flow
https://gorules.io/docs/user-manual/decision-modeling/loops

Most important properties will be outputPath and/or inputPath in your case.