Fixed #29545 -- Fixed using filter lookups againts nested subquery expressions.

[charettes]

This is necessary to allow filter lookups against nested subquery expressions to properly resolve their OuterRefs to Cols.

Thanks Oskar Persson for the simplified test case.

[felixxm]

@charettes Thanks 🚀

[OskarPersson]

Is there any chance we will see this in 2.2.5? I can't see it listed in the changelog

[felixxm]

@OskarPersson No, this patch doesn't qualify for a backport.

[OskarPersson]

Why is that? What makes a patch qualify for a backport or not, especially for a LTS?

[felixxm]

It is not a regression or a bug in a new feature.

[OskarPersson]

I'm sorry, but doesn't it collide with the documentation for the same release then? Isn't the following statement incorrect without this patch? Without it, it would crash.

Instances of OuterRef may be used in conjunction with nested instances of Subquery to refer to a containing queryset that isn’t the immediate parent.

https://docs.djangoproject.com/en/2.2/ref/models/expressions/#referencing-columns-from-the-outer-queryset

[felixxm]

First of all this works in most of cases, issue is only when resolving nested subqueries used in lhs. Secondly Subquery is not a feature added in Django 2.2 and this issue was in Django since 2.0.

[OskarPersson]

I see, guess I'll keep my workarounds for 3.0 then :)