Chained associated against pg_scope and regular scope fail

[doits]

This PR only adds failing tests for now. (New PR based of master in comparison to #241)

Looks like the error has the same symptoms like #235 but a different cause ... here it seems to be the automatic table aliasing done by rails. Let me explain.

If you simply do Person.joins(:houses).to_sql, everything is fine:

Person.joins(:houses).to_sql

SELECT \"with_model_people_41998\".* FROM \"with_model_people_41998\"
INNER JOIN \"with_model_houses_41998\"
ON \"with_model_houses_41998\".\"person_id\" = \"with_model_people_41998\".\"id\"

But if you introduce a second join to the same table, even by a string option, it automatically aliases the first join. (the following query is invalid sql but shows what rails does):

Person.joins(:houses).joins(
"INNER JOIN \"with_model_houses_41998\" ON"
).to_sql

SELECT \"with_model_people_41998\".* FROM \"with_model_people_41998\"
INNER JOIN \"with_model_houses_41998\" \"houses_with_model_people_41998\"
ON \"houses_with_model_people_41998\".\"person_id\" = \"with_model_people_41998\".\"id\"
INNER JOIN \"with_model_houses_41998\" ON

Interesting thing is, that if you change the join string to INNER JOI ... (so only remove the N from JOIN) or remove the last N ("INNER JOIN \"with_model_houses_41998\" O), no alias is created:

Person.joins(:houses).joins(
"INNER JOIN \"with_model_houses_41998\" O"
).to_sql

SELECT \"with_model_people_41998\".* FROM \"with_model_people_41998\"
INNER JOIN \"with_model_houses_41998\"
ON \"with_model_houses_41998\".\"person_id\" = \"with_model_people_41998\".\"id\"
INNER JOIN \"with_model_houses_41998\" O

The problem lies in the fact that this table aliasing is also done when the join is happening in a subquery:

Person.joins(:houses).joins(
"INNER JOIN (select * from something INNER JOIN \"with_model_houses_41998\" ON) table_alias"
).to_sql

SELECT \"with_model_people_41998\".* FROM \"with_model_people_41998\"
INNER JOIN \"with_model_houses_41998\" \"houses_with_model_people_41998\"
ON \"houses_with_model_people_41998\".\"person_id\" = \"with_model_people_41998\".\"id\"
INNER JOIN (select * from something INNER JOIN \"with_model_houses_41998\" ON) table_alias

I'm not sure, but this sub query should not change the outer query and the table aliasing done by rails is unnecessary (or not?).

A solution on the pg_search side is simply to do table aliasing in the subquery by itself:

Person.joins(:houses).joins(
"INNER JOIN (select * from something INNER JOIN \"with_model_houses_41998\" \"pg_table_alias\" ON) table_alias"
).to_sql

SELECT \"with_model_people_41998\".* FROM \"with_model_people_41998\"
INNER JOIN \"with_model_houses_41998\"
ON \"with_model_houses_41998\".\"person_id\" = \"with_model_people_41998\".\"id\"
INNER JOIN (select * from something INNER JOIN \"with_model_houses_41998\" \"pg_table_alias\" ON) table_alias

But this means the join must be done by hand in association.rb or at least I do not know any way to specify a table alias manually in .joins().

So main question are:

• Is automatic table aliasing done by rails / activerecord because of a join in a subquery unnecessary? If yes, maybe report this to the rails team and they can remove it ...
• Can pg_search set a table alias manually in the subquery join to stop automatic table aliasing?
• Or is it much simpler to fix and the problem lies elsewhere?