#with cannot be used with strings in 6.1

[dark-panda]

Steps to reproduce

Using #with with strings instead of relations stopped working between Rails 6.0 and 6.1. Specifically, the following commit caused the break:

596469d

In Rails 6.0, you could do things like

popular_posts_from_cte = Post.with("popular_posts AS (SELECT * FROM posts WHERE views_count > 100)").from("popular_posts AS posts")

However, that broke in Rails 6.1 with the following exception as there is no case to handle strings in the case statement:

TypeError: no implicit conversion of nil into String

A patch to fix the issue is forth coming.

Expected behavior

The SQL should generate when strings are used in #with values.

Actual behavior

A TypeError is raised.

System configuration

Rails version: 6.1.3.2

Ruby version: 2.7.3

[HParker]

A patch to fix the issue is forth coming.

Thanks for taking on this patch @dark-panda! I look forward to reading it ❤️

I am a bit confused though, I didn't know there was a with method on model classes.

I don't seem to have it in a new rails app.

Article.method(:with)
NameError: undefined method `with' for class `#<Class:Article(id: integer, title: string, created_at: datetime, updated_at: datetime, user_id: integer)>'
from (pry):6:in `method'

Where is that method coming from? Is it another gem, or maybe I am doing something silly.

[ghiculescu]

@HParker looks like it comes from here https://github.com/rails/rails/blob/main/activerecord/lib/arel/select_manager.rb#L223, I think https://github.com/vlado/activerecord-cte enhances it.

[eileencodes]

Technically arel is a private API, I don't know if we want to allow strings in the with API.

[HParker]

Ah, so without activerecord-cte I have to do Article.all.arel.with("select 1"). activerecord-cte Seems to use a lot of arel. I wonder if activerecord-cte could be patched to handle strings instead of making a change in rails 🤔 .

[rafaelfranca]

In this case I think it is fine since Arel used to work in this way and a new feature to arel we introduced broke it.

[dark-panda]

This was discovered while I was writing a patch for activerecord-cte to fix a kinda-sorta-related issue with the gem. That PR is up at vlado/activerecord-cte#3. Basically, all specs were working when testing against Rails 5.2 and 6.0 but then one particular test was failing in 6.1.