Auto-completion wrongly suggesting size field when using terms agg within composite agg

[vladpro25]

Closes: #53112

Describe the issue:

[Console] Auto-completion wrongly suggesting size field when using terms agg within composite agg

Steps to reproduce

Using Dev Tools autocomplete:

1. Create a composite aggregation
2. Use terms aggregation as source
   (e.g., follow this tutorial: https://www.elastic.co/blog/composite-aggregations-elasticsearch-pizza-delivery-metrics)

Final result

terms aggregation within composite aggregation does not allow for size field.

Confirmation

[vladpro25]

@elasticmachine merge upstream

[elasticmachine]

Pinging @elastic/kibana-stack-management (Team:Stack Management)

[yuliacech]

Hi @vladpro25, thank you so much for opening this PR!
If I understand correctly, your suggested change will remove size parameter from terms aggregation. But the linked issue requests to remove size fromterms aggregation only when it's used as a source in composite aggregation. Could you please confirm with the Elasticsearch team that size parameter can't be used when terms is a source for composite aggregation? I was not able to find this in the docs.
Terms aggregation docs
Composite aggregation docs

[kibana-ci]

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Metrics [docs]

✅ unchanged

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream

cc @vladpro25

[alexwizp]

@vladpro25 it's definitely wrong fix. size should be reverted for terms aggregation.

@yuliacech I've tried execute composite aggregation locally and looks like ES doesn't supports that case:

But not sure that it's too easy to understand that we are inside of composite agg. @vladpro25 let's discuss it offline tomorrow

[yuliacech]

Thanks for checking this, @alexwizp! I opened this docs issue elastic/elasticsearch#81431 to add this information to the Elasticsearch guide.

[yuliacech]

Hi @vladpro25, the current assumption in the code is that aggregations behave the same when used alone and when used as a source for other aggregations, like terms is used inside composite aggregation. This makes excluding size param from the terms aggregation only when used as a source difficult.