Issue with RSpec::Matchers.define_negated_matcher and active_support/core_ext/object/with.rb

[vimalloc]

Hello!

We are running into an issue that was introduced when upgrading from rails 7.0.8 to 7.1.1, which is triggered by the newly added Object#with method.

Steps to reproduce

• Define a negated matcher that can acceptswith (ex: enqueue_job.with('foo'))
• Attempt to run a test using both the negated matcher and with
• Notice we receive a wrong number of arguments error, and that the stacktrace indicates that it's trying to call Object#with, as defined in activesupport-7.1.1/lib/active_support/core_ext/object/with.rb

# frozen_string_literal: true

require "bundler/inline"

gemfile(true) do
  source "https://rubygems.org"
  git_source(:github) { |repo| "https://github.com/#{repo}.git" }
  gem "sqlite3"
  gem 'rails', '~> 7.1'
  gem 'rspec-rails'
end

require "rails/all"

ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
ActiveRecord::Base.logger = Logger.new(STDOUT)
ActiveJob::Base.queue_adapter = :test

require 'rspec/rails'
require 'rspec/autorun'

# This is the thing that is eventually leading to an ArgumentError being raised when it shouldn't
RSpec::Matchers.define_negated_matcher(:not_enqueue_job, :enqueue_job)

RSpec.describe 'downcase' do
  it 'works' do
    expect('Foo'.downcase).to eq('foo')
  end

  it 'does not enqueue a job' do
    expect { 'Foo'.downcase }.to not_enqueue_job.with('Bar')
  end
end

Expected behavior

The test passes.

Actual behavior

  1) downcase does not enqueue a job
     Failure/Error: expect { 'Foo'.downcase }.to not_enqueue_job.with('Bar')

     ArgumentError:
       wrong number of arguments (given 1, expected 0)
     # ./example_spec.rb:30:in `block (2 levels) in <top (required)>'

Notes:

This is happening with a few different matchers we use, not just the not_enqueue_job one. We are using these negated matchers because we have a lot of specs that assert a couple different things using .and <negated_matcher>.

Rspec-mocks ran into a similar issue as this: rspec/rspec-mocks#1530.

System configuration

Rails version:
7.1.1

Ruby version:
3.2.2

[byroot]

I'm trying to run your repro script, but it doesn't execute the tests, how do you do that?

[byroot]

Nevermind, it's just missing require "rspec/autorun"

[fatkodima]

I think, Object#with comes with this require

rails/railties/lib/rails/configuration.rb

Line 4 in 14294c0

require "active_support/core_ext/object"

Should we do only require "active_support/core_ext/object/deep_dup" here?

[vimalloc]

Nevermind, it's just missing require "rspec/autorun"

Doh, thank you. Sorry, I was running it using nvim-test, which just did the right thing for me 😅

[byroot]

@fatkodima that's not the issue. rspec-matchers should work even in the presence of Object#with.

[byroot]

Ok. I found the issue. not_enqueue_job returns a Rspec::Matchers::AliasedNegatedMatcher. That class relies on method_missing, so now that Object#with was introduced it no longer intercept .with.

The clean fix would be for it to inherit from BasicObject, I'll try to work on a patch for that.

As a quick workaround you can add:

Rspec::Matchers::AliasedNegatedMatcher.undef_method(:with)

In you spec_helper or something.

[vimalloc]

Awesome, that unblocked me! Thank you for looking at this! <3

[byroot]

Not quite production ready, but the clean fix will look something like that: rspec/rspec-expectations#1434

I'll try to polish it tomorrow.

Now if you don't mind, given this isn't a Rails bug, I'll close.