Postgres adapter does not cast ActiveSupport::Duration to interval in array condition

[aramgre]

When passing an ActiveSupport::Duration to an Active Record where query on Postgres, it will be converted to an ISO 8601 string in a hash condition on an interval column, but not in an array condition.

For interval columns, it would be convenient to be able to pass ActiveSupport::Duration in either hash or array conditions. However, some applications probably depend on the existing behavior to pass ActiveSupport::Duration as a numeric type so any change might have to be opt-in.

Steps to reproduce

# frozen_string_literal: true

require "bundler/inline"

gemfile(true) do
  source "https://rubygems.org"

  git_source(:github) { |repo| "https://github.com/#{repo}.git" }

  gem "rails", github: "rails/rails", branch: "main"
  gem "pg"
  gem "byebug"
end

require "active_record"
require "minitest/autorun"
require "logger"

# docker run --rm -e POSTGRES_PASSWORD=postgres -p 9999:5432 postgres
ActiveRecord::Base.establish_connection("postgres://postgres:postgres@localhost:9999/postgres")
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :movies, force: true do |t|
    t.interval :runtime
  end
end

class Movie < ActiveRecord::Base
end

class BugTest < Minitest::Test
  def test_duration
    Movie.create!(runtime: 2.hours)
    Movie.create!(runtime: 90.minutes)
    Movie.create!(runtime: 3.hours + 30.minutes)

    # SELECT COUNT(*) FROM "movies" WHERE "movies"."runtime" < $1  [["runtime", "PT3H"]]
    assert_equal 2, Movie.where(runtime: ...3.hours).count

    # SELECT COUNT(*) FROM "movies" WHERE (runtime < 10800)
    # ActiveRecord::StatementInvalid: PG::UndefinedFunction: ERROR:  operator does not exist: interval < integer
    assert_equal 2, Movie.where('runtime < ?', 3.hours).count
  end
end

Expected behavior

When passing a duration in an array condition, it should be converted to a valid interval input (e.g., ISO 8601)

https://www.postgresql.org/docs/current/datatype-datetime.html#DATATYPE-INTERVAL-INPUT

Actual behavior

The duration get converted to an integer seconds which Postgres can't cast to an interval.

System configuration

Rails version:
Using rails 7.1.0.alpha from https://github.com/rails/rails.git (at main@6a55aff)
Ruby version:
ruby 2.7.1p83 (2020-03-31 revision a0c7c23c9c) [x86_64-darwin19]

[ghiculescu]

@aramgre I see you made a commit for this aramgre@785f1a6 did you want to make a PR?

[aramgre]

@ghiculescu opened a PR here #44438. However, I'm not sure of the process for breaking changes, please let me know if I need to include a deprecation notice in the PR or create a separate PR with the deprecation notice, etc.