fix: prevents runtime error on undefined facets

[gerardosabetta]

It is not safe to assume that facets is going to be in the response

As discussed in this slack thread https://elasticstack.slack.com/archives/C018C7B9T5F/p1679935623878799

The backend for app search sometimes does not include a facets in the response. I'm able to reproduce when our product is deployed to a new environment and the document count is zero.

{"meta":{"alerts":[],"warnings":[],"precision":3,"page":{"current":1,"total_pages":1,"total_results":0,"size":0},"engine":{"name":"assessments-onprem","type":"default"},"request_id":"0c98a347-a054-49f2-b8dd-f433449791c7"},"results":[]}

[joemcelroy]

Thank you! Will need some unit tests to validate the change. Also added a comment

[gerardosabetta]

Any updates on this?

[joemcelroy]

The change looks good but the testcase is incorrect. What you want in the testcase is to validate that the request doesn't have the presence of facets object. I still see in the request fixture, the facets object thats populated with a facet configuration (which is expected with this testcase).

I think you should see this behavior (without the fix) with the following configuration:

const result = await client.search("dog", {
         ...config,
         filters: {
           license: "BSD"
         },
         facets: {
           dependencies: [{ type: "value", size: 3 }]
         },
         disjunctiveFacets: ["license"]
       });

The other way is to filter disjunctiveFacets array that are only present in facets objects too.

[gerardosabetta]

I don't think that's correct; I don't want to validate the request not having the presence of the facet object. It's the response what I really care about. That's why I do the assertion down below. This is really similar to the original request that produced the issue for me if you look back to the original slack thread.

[gerardosabetta]

The behavior doesn't reproduce by modifying the request as you suggested. It produces a different error:

Because Facet-Only request goes out to fetch the disjunctive "license" tag

[gerardosabetta]

@joemcelroy any updates?