[CI] EsqlClientYamlIT test {p0=esql/190_lookup_join/alias-repeated-index} failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-intake #23566 / 8.19.0_bwc-snapshots
• elasticsearch-intake #23567 / 8.19.0_bwc-snapshots

Reproduction Line:

./gradlew ":x-pack:plugin:esql:qa:server:mixed-cluster:v8.19.0#yamlRestTest" -Dtests.class="org.elasticsearch.xpack.esql.qa.mixed.EsqlClientYamlIT" -Dtests.method="test {p0=esql/190_lookup_join/alias-repeated-index}" -Dtests.seed=A53CADAE04ADF1C -Dtests.bwc=true -Dtests.locale=ff-Latn-GN -Dtests.timezone=Asia/Ulan_Bator -Druntime.java=24

Applicable branches:
main

Reproduces locally?:
N/A

Failure History:
See dashboard

Failure Message:

java.lang.AssertionError: Failure at [esql/190_lookup_join:204]: expected [2xx] status code but api [esql.query] returned [500 Internal Server Error] [{"error":{"root_cause":[{"type":"esql_illegal_argument_exception","reason":"Aliases and index patterns are not allowed for LOOKUP JOIN []","stack_trace":"org.elasticsearch.xpack.esql.EsqlIllegalArgumentException: Aliases and index patterns are not allowed for LOOKUP JOIN []\n\tat org.elasticsearch.xpack.esql.enrich.LookupFromIndexService$TransportRequest.writeTo(LookupFromIndexService.java:193)\n\tat org.elasticsearch.server@8.19.0-SNAPSHOT/org.elasticsearch.transport.OutboundHandler.serializeMessageBody(OutboundHandler.java:372)\n\tat org.elasticsearch.server@8.19.0-SNAPSHOT/org.elasticsearch.transport.OutboundHandler.serialize(OutboundHandler.java:313)\n\tat org.elasticsearch.server@8.19.0-SNAPSHOT/org.elasticsearch.transport.OutboundHandler.sendMessage(OutboundHandler.java:233)\n\tat org.elasticsearch.server@8.19.0-SNAPSHOT/org.elasti
[truncated]

Issue Reasons:

• [main] 2 consecutive failures in test test {p0=esql/190_lookup_join/alias-repeated-index}
• [main] 2 consecutive failures in step 8.19.0_bwc-snapshots
• [main] 2 consecutive failures in pipeline elasticsearch-intake
• [main] 2 failures in test test {p0=esql/190_lookup_join/alias-repeated-index} (100.0% fail rate in 2 executions)
• [main] 2 failures in step 8.19.0_bwc-snapshots (100.0% fail rate in 2 executions)
• [main] 2 failures in pipeline elasticsearch-intake (100.0% fail rate in 2 executions)

Note:
This issue was created using new test triage automation. Please report issues or feedback to es-delivery.

[elasticsearchmachine]

This has been muted on branch main

Mute Reasons:

• [main] 2 consecutive failures in test test {p0=esql/190_lookup_join/alias-repeated-index}
• [main] 2 consecutive failures in step 8.19.0_bwc-snapshots
• [main] 2 consecutive failures in pipeline elasticsearch-intake
• [main] 2 failures in test test {p0=esql/190_lookup_join/alias-repeated-index} (100.0% fail rate in 2 executions)
• [main] 2 failures in step 8.19.0_bwc-snapshots (100.0% fail rate in 2 executions)
• [main] 2 failures in pipeline elasticsearch-intake (100.0% fail rate in 2 executions)

Build Scans:

• elasticsearch-intake #23566 / 8.19.0_bwc-snapshots
• elasticsearch-intake #23567 / 8.19.0_bwc-snapshots

[elasticsearchmachine]

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

[alex-spies]

I'm confused; for 8.19 before the backport of #128519, this test shouldn't even have run - and after the backport, it should've passed.

@luigidellaquila , could you please take a look?

[luigidellaquila]

Checking

[luigidellaquila]

Apparently the problem is a newline in the yaml file

---

"Alias as lookup index":

vs

---
"Alias as lookup index":

That's enough to make the test ignore the capabilities.
I'm fixing the tests now