ConnectionNotEstablished when using connection on AR::Base abstract subclass

I’m using AR outside of Rails and calling establish_connection on an
ActiveRecord::Base abstract_class subclass (to protect my connection
in case anyone else is using AR). It was working just fine with AR
3.0.9, but I recently attempted to upgrade to AR 3.2.2. Now, when I
hit a “nested” query from a has_many, I get a
ActiveRecord::ConnectionNotEstablished. If I call
establish_connection on ActiveRecord::Base, instead of the DB abstract
subclass, everything works fine.

I’ve stripped out a minimal example below, which should be self-
contained, as well as a snippet that highlights the problem. Is this
a bug, or does my code need to change to support AR 3.2 (also fails on
3.1).

This is the offending code:

Employer.all.each do |employer|
  p employer.employees
end

Self-contained script:

#!/bin/env ruby

require 'sqlite3'
require 'active_record'
require 'logger'

ActiveRecord::Base.logger = Logger.new STDOUT

class DB < ActiveRecord::Base
  self.abstract_class = true
end
class Employer < DB
  has_many :employees
end
class Employee < DB
end

# If establish_connection is instead called on AR::Base, this

works fine.
DB.establish_connection(:adapter => “sqlite3”,
:database => “./db.sqlite”)

DB.connection.create_table(:employers) do |t|
  t.primary_key :id
end
DB.connection.create_table(:employees) do |t|
  t.primary_key :id
  t.integer :employer_id
end

Employer.create!.employees << Employee.create!

Employer.all.each do |employer|
  p employer.employees
end

Output:

D, [2012-03-02T16:22:36.852779 #14148] DEBUG -- :    (1.7ms)

select sqlite_version()
D, [2012-03-02T16:22:36.854577 #14148] DEBUG – : (1.3ms)
CREATE TABLE “employers” (“id” INTEGER PRIMARY KEY AUTOINCREMENT NOT
NULL)
D, [2012-03-02T16:22:36.857462 #14148] DEBUG – : (2.0ms)
CREATE TABLE “employees” (“id” INTEGER PRIMARY KEY AUTOINCREMENT NOT
NULL, “employer_id” integer)
D, [2012-03-02T16:22:36.879564 #14148] DEBUG – : (0.1ms)
begin transaction
D, [2012-03-02T16:22:36.884458 #14148] DEBUG – : SQL (3.1ms)
INSERT INTO “employers” VALUES(NULL)
D, [2012-03-02T16:22:36.885693 #14148] DEBUG – : (0.8ms)
commit transaction
D, [2012-03-02T16:22:36.956479 #14148] DEBUG – : (0.1ms)
begin transaction
D, [2012-03-02T16:22:36.964279 #14148] DEBUG – : SQL (5.8ms)
INSERT INTO “employees” (“employer_id”) VALUES (?) [[“employer_id”,
nil]]
D, [2012-03-02T16:22:36.965657 #14148] DEBUG – : (0.9ms)
commit transaction
D, [2012-03-02T16:22:36.966902 #14148] DEBUG – : (0.1ms)
begin transaction
D, [2012-03-02T16:22:36.969294 #14148] DEBUG – : (0.5ms)
UPDATE “employees” SET “employer_id” = 1 WHERE “employees”.“id” = 1
D, [2012-03-02T16:22:36.972066 #14148] DEBUG – : (2.3ms)
commit transaction
D, [2012-03-02T16:22:36.973350 #14148] DEBUG – : Employer Load
(0.3ms) SELECT “employers”.
FROM “employers”
/Users/mlartz/.rvm/gems/ruby-1.9.3-p0@tmp/gems/activerecord-3.2.2/
lib/active_record/connection_adapters/abstract/connection_pool.rb:
374:in retrieve_connection': ActiveRecord::ConnectionNotEstablished (ActiveRecord::ConnectionNotEstablished) from /Users/mlartz/.rvm/gems/ruby-1.9.3-p0@tmp/gems/ activerecord-3.2.2/lib/active_record/connection_adapters/abstract/ connection_specification.rb:168:inretrieve_connection’
from /Users/mlartz/.rvm/gems/ruby-1.9.3-p0@tmp/gems/
activerecord-3.2.2/lib/active_record/connection_adapters/abstract/
connection_specification.rb:142:in connection' from /Users/mlartz/.rvm/gems/ruby-1.9.3-p0@tmp/gems/ activerecord-3.2.2/lib/active_record/associations/alias_tracker.rb: 75:inconnection’
from /Users/mlartz/.rvm/gems/ruby-1.9.3-p0@tmp/gems/
activerecord-3.2.2/lib/active_record/associations/alias_tracker.rb:
54:in initial_count_for' from /Users/mlartz/.rvm/gems/ruby-1.9.3-p0@tmp/gems/ activerecord-3.2.2/lib/active_record/associations/alias_tracker.rb: 12:inblock in initialize’
from /Users/mlartz/.rvm/gems/ruby-1.9.3-p0@tmp/gems/
activerecord-3.2.2/lib/active_record/associations/alias_tracker.rb:
29:in yield' from /Users/mlartz/.rvm/gems/ruby-1.9.3-p0@tmp/gems/ activerecord-3.2.2/lib/active_record/associations/alias_tracker.rb: 29:indefault’
from /Users/mlartz/.rvm/gems/ruby-1.9.3-p0@tmp/gems/
activerecord-3.2.2/lib/active_record/associations/alias_tracker.rb:
29:in aliased_name_for' from /Users/mlartz/.rvm/gems/ruby-1.9.3-p0@tmp/gems/ activerecord-3.2.2/lib/active_record/associations/alias_tracker.rb: 17:inaliased_table_for’
from /Users/mlartz/.rvm/gems/ruby-1.9.3-p0@tmp/gems/
activerecord-3.2.2/lib/active_record/associations/join_helper.rb:15:in
block in construct_tables' from /Users/mlartz/.rvm/gems/ruby-1.9.3-p0@tmp/gems/ activerecord-3.2.2/lib/active_record/associations/join_helper.rb:14:ineach’
from /Users/mlartz/.rvm/gems/ruby-1.9.3-p0@tmp/gems/
activerecord-3.2.2/lib/active_record/associations/join_helper.rb:14:in
construct_tables' from /Users/mlartz/.rvm/gems/ruby-1.9.3-p0@tmp/gems/ activerecord-3.2.2/lib/active_record/associations/association_scope.rb: 37:inadd_constraints’
from /Users/mlartz/.rvm/gems/ruby-1.9.3-p0@tmp/gems/
activerecord-3.2.2/lib/active_record/associations/association_scope.rb:
31:in scope' from /Users/mlartz/.rvm/gems/ruby-1.9.3-p0@tmp/gems/ activerecord-3.2.2/lib/active_record/associations/association.rb:98:inassociation_scope’
from /Users/mlartz/.rvm/gems/ruby-1.9.3-p0@tmp/gems/
activerecord-3.2.2/lib/active_record/associations/association.rb:87:in
scoped' from /Users/mlartz/.rvm/gems/ruby-1.9.3-p0@tmp/gems/ activerecord-3.2.2/lib/active_record/associations/ collection_association.rb:380:infind_target’
from /Users/mlartz/.rvm/gems/ruby-1.9.3-p0@tmp/gems/
activerecord-3.2.2/lib/active_record/associations/
collection_association.rb:333:in load_target' from /Users/mlartz/.rvm/gems/ruby-1.9.3-p0@tmp/gems/ activerecord-3.2.2/lib/active_record/associations/collection_proxy.rb: 44:inload_target’
from /Users/mlartz/.rvm/gems/ruby-1.9.3-p0@tmp/gems/
activerecord-3.2.2/lib/active_record/associations/collection_proxy.rb:
87:in method_missing' from test.rb:38:inp’
from test.rb:38:in block in <main>' from test.rb:37:ineach’
from test.rb:37:in `’

Any ideas?