Transaction strategy configured with symbol(connection name) does not work

(I will post my suggestion next to this report.)

Summary

When we add another database to a cleaner by specifying a symbol (connection name) with the :transaction strategy, it does not open a transaction.

Look at the reproduction below. Even though the cleaner is configured to clean :db => :bar with the transaction strategy, the transaction is not opened*.

(*In fact, a transaction is opened on ActiveRecord::Base.connection instead.)

Reproduction

#!/usr/bin/env ruby

require "bundler/inline"

gemfile(true) do
  source 'https://rubygems.org'
  gem 'rails', '~> 7.0.0'
  gem 'sqlite3'
  gem 'rspec'
  gem 'database_cleaner-active_record', git: "https://github.com/DatabaseCleaner/database_cleaner-active_record.git", ref: "aafa5b2"
end

require "yaml"

ActiveRecord::Base.configurations = YAML.load(<<~YAML)
  foo:
    adapter: sqlite3
    database: ":memory:"
  bar:
    adapter: sqlite3
    database: ":memory:"
YAML

RSpec.describe do
  before do
    ActiveRecord::Base.establish_connection :foo

    class Bar < ActiveRecord::Base
      establish_connection :bar
    end
  end

  it "should open a transaction on Bar" do
    cleaner = DatabaseCleaner::Cleaners.new
    cleaner[:active_record, :db => :bar].strategy = :transaction
    cleaner.cleaning do
      # expected: true
      #      got: false
      expect(Bar.connection.transaction_open?).to eq(true)
    end
  end

  it "should not open a transaction on ActiveRecord::Base where we removed it from cleaner" do
    cleaner = DatabaseCleaner::Cleaners.new
    cleaner[:active_record].strategy = nil
    cleaner[:active_record, :db => :bar].strategy = :transaction
    cleaner.cleaning do
      # expected: false
      #      got: true
      expect(ActiveRecord::Base.connection.transaction_open?).to eq(false)
    end
  end
end

Suggested Solution

In the reproduction above, try replacing all the :db => :bar with :db => Bar. The test passes.

Looking into the database_cleaner/active_record/base.rb, it is managing to obtain the ActiveRecord class from a given connection name.

It makes the code have too much responsibility and very complex. That is, it is reading ActiveRecord::Base.configurations, reading config/database.yml, and searching through connection pools and ActiveRecord classes.

This complexity can easily bring bugs such as #10, #18 and #97.

Though it is a breaking change... if we make the cleaner only accept an ActiveRecord class object as a value for :db option, doesn't database_cleaner/active_record/base.rb become far simpler and reduce the possibility of bugs so much?

I've been hitting a similar issue when using a dual database setup, one is postgresql, the other is clickhouse.
The former is cleaned with transaction and the latter via truncation.

When using symbol as the database name, the first spec content is never rolled back and is part of the state in the subsequent specs, causing failures down the line.

I haven't found the underlying issue (yet) but the solution mentionned here is a workaround. I've replaced

  pg_cleaner = DatabaseCleaner[:active_record, db: :postgres]
  ch_cleaner = DatabaseCleaner[:active_record, db: :clickhouse]

by

  pg_cleaner = DatabaseCleaner[:active_record, db: APostgresModel]
  ch_cleaner = DatabaseCleaner[:active_record, db: AClickHouseModel]

and everything works as expected now

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Transaction strategy configured with symbol(connection name) does not work #100

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Transaction strategy configured with symbol(connection name) does not work #100

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kaorukobo commented on Mar 2, 2024

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elthariel commented on Jun 2, 2026

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