Fix superclass functional interface resolution in Painless

[jdconrad]

A recent change [1] to how we load our allow list changed the resolution for how Painless looks up methods of super classes. However, functional interface loading was not changed which caused a bug where a functional interface would not look at its super interfaces for the functional interface method [2].

This fixes the issue by going through each super interface until the functional interface method is found when the target interface doesn't have the functional interface method.

[1] #76955
[2] #81696

[elasticmachine]

Pinging @elastic/es-core-infra (Team:Core/Infra)

[elasticsearchmachine]

Hi @jdconrad, I've created a changelog YAML for you.

[elasticsearchmachine]

Hi @jdconrad, I've updated the changelog YAML for you.

[elasticsearchmachine]

Hi @jdconrad, I've updated the changelog YAML for you.

[jdconrad]

@elasticmachine run elasticsearch-ci/docs-check

[jdconrad]

@elasticmachine run elasticsearch-ci/part-1

[jdconrad]

@elasticmachine run elasticsearch-ci/part-1

[jdconrad]

@elasticmachine run elasticsearch-ci/docs-check

[elasticsearchmachine]

Hi @jdconrad, I've updated the changelog YAML for you.

[stu-elastic]

Can you add the following test?

    public void testUnaryOperator() {
        assertEquals("doremi", exec("List lst = ['abc', '123']; lst.replaceAll(f -> f.replace('abc', 'doremi')); lst.get(0);"));
        assertEquals("doremi", exec("def lst = ['abc', '123']; lst.replaceAll(f -> f.replace('abc', 'doremi')); lst.get(0);"));
    }

Can you thank @megglos and @TheFireCookie in the commit message?

We'll also have to write up a Known issues section in the 7.16 release notes

[elasticsearchmachine]

💚 Backport successful

Status	Branch	Result
✅	8.0
✅	7.16