ESQL: Fail in AggregateFunction when LogicPlan is not an Aggregate

[kanoshiou]

Trigger Verifier failure in AggregateFunction if the LogicPlan is not an Aggregate.

Closes #124311

[elasticsearchmachine]

Pinging @elastic/es-analytical-engine (Team:Analytics)

[ivancea]

buildkite test this

[ivancea]

Thanks for your contribution! It looks good!
About the RRF command (First comment 👀), I'll ping @ioanatia in case she sees something I don't, as she knows the command far better, and so they know about this change.
Otherwise, after it's changed to work with RRF and the tests pass, it should be fine!

[ivancea]

Could you add another test with multiple aggs in the same WHERE/EVAL, or both in the same query with an agg each?
You can test it like here:

elasticsearch/x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/analysis/VerifierTests.java

Lines 1010 to 1015 in a8be56f

	public void testNotFoundFieldInNestedFunction() {
	assertEquals("""
	1:30: Unknown column [missing]
	line 1:43: Unknown column [not_found]
	line 1:23: Unknown column [avg]""", error("from test | stats c = avg by missing + 1, not_found"));
	}

I'm asking this because the RRF test sends many repeated errors (Because each "subblan" of the RRF has the same source). It shouldn't happen here at all, but just as a double-check

[kanoshiou]

Thank you for reviewing @ivancea @ioanatia !😊

The branch has been updated. Please take a look when you have a moment.

[ivancea]

buildkite test this

[alex-spies]

Thanks a lot @kanoshiou ! This LGTM. I only have a final test suggestion that I think we should implement before merging this.

[alex-spies]

I think we should add test cases where an aggregate function ends up in the ROW command. The following currently gives 500:

row language_code = count(2)

While supremely paranoid, we could also throw in test cases for dissect and grok, like row x = 1 | dissect avg(1) "foo" and similarly with grok. (This doesn't give 500 on current main.)

[kanoshiou]

Thank you for reviewing! I’ve added the tests in c7d867c.

[alex-spies]

Thanks @kanoshiou , let's !

[ivancea]

buildkite test this

[ivancea]

🚀

[elasticsearchmachine]

💔 Backport failed

Status	Branch	Result
❌	8.x	Commit could not be cherrypicked due to conflicts
❌	9.0	Commit could not be cherrypicked due to conflicts

You can use sqren/backport to manually backport by running backport --upstream elastic/elasticsearch --pr 124446