Count query for fetchPage is incorrect for queries with raw select and groupBy

[squgeim]

Introduction

For a query that contains a raw select and is grouped by those columns, the count query generated by fetchPage is incorrect and fails. This issues was introduced in our system after we upgraded Bookshelf from 0.10.3 to 1.2.0, and knex from 0.13.0 to 0.21.12.

Issue Description

We have queries that extracts year and month from a single date column. We then group them by year and month and select some aggregate functions. When we do fetchPage, the count query generate selects count(distinct("year", "month")) directly from the table, which fails because these columns do not exist.

I am not sure about the implementation so can't comment on what the fix would be, but it clear that this worked as expected in the older version so it should be a bug.

Steps to reproduce issue

This is a simplified query that replicates the bug (Postgres):

AvgTouchesToEnroll.query((qb) => {
  qb.where('user_id', query.userId);
  qb.select(
    knex.raw(
      'extract(year from date) :: integer as year, extract(month from date) :: integer as month, sum(avg_touches) as avg_touches, sum(count) as count'
    )
  );
  qb.groupBy('year');
  qb.groupBy('month');
}).fetchPage({
  page: query.page,
  pageSize: query.pageSize,
});

The generated count query and error is:

select count(distinct("year", "month")) from "average_touches_to_enroll" where "user_id" = $1 - column "year" does not exist

Expected behaviour

It should return the requested page with pagination data.

Actual behaviour

It fails with an SQL error.