Expression in `in` is broken in 7.1.4 and 8.0.0

[blackst0ne]

I am upgrading a rails 4.2 application to 5.0.
I have some constructions based on arel which stopped working on arel 7.1.4 (rails 5.0.6).

I have tested them on these versions:

• 6.0.4 (rails 4.2.10) works.
• 7.1.4 (rails 5.0.6) doesn't work.
• 8.0.0 (rails 5.1.5) doesn't work.
• 9.0.0 (rails 5.2.0) works.

Code (simplified for readability) is this:

# Arel 6.0.4 and 9.0.0
> sql = Arel.sql(User.select(:id).to_sql)
=> "SELECT \"users\".\"id\" FROM \"users\""
> User.where(User.arel_table[:id].in(sql)).to_sql
=> "SELECT \"users\".* FROM \"users\" WHERE \"users\".\"id\" IN (SELECT \"users\".\"id\" FROM \"users\")"

# Arel 7.1.4 and 8.0.0
> sql = Arel.sql(User.select(:id).to_sql)
=> "SELECT \"users\".\"id\" FROM \"users\""
> User.where(User.arel_table[:id].in(sql)).to_sql
=> "SELECT \"users\".* FROM \"users\" WHERE \"users\".\"id\" IN (0)"

What can I do to get my code work again on 7.1.4 and 8.0.0 (as I'm going to upgrade to rails 5.1 later)?

[blackst0ne]

/cc @matthewd @rafaelfranca

[yorickpeterse]

For clarification: the Rails application in question is GitLab's Rails application.

[rafaelfranca]

First first step is trying to find which commit fixed it on 9.0. After that we can backport to the other versions.

[blackst0ne]

I checked locally. It seems Arel is not affected, everything is just fine. :thinking:

Checking ActiveRecord...

[matthewd]

Per #523, Arel development is moving to rails/rails.

If this issue is still relevant, please consider reopening it over there. (Note that the Rails repository does not accept feature request issues, and requires reproduction steps that rely on Active Record's documented API.)

[andsip]

First first step is trying to find which commit fixed it on 9.0. After that we can backport to the other versions.

I think this was fixed in 9.0.0 via b416fca3.