ActiveSupport::TestCase teardown error: undefined method `keys' for nil

[searls]

Getting the following error. I've seen it four or five times but every time I've cleared it I haven't been able to create a minimal reproduction:

NoMethodError: undefined method `keys' for nil
    /Users/justin/.rbenv/versions/3.3.0/lib/ruby/gems/3.3.0/gems/dotenv-3.1.0/lib/dotenv/diff.rb:25:in `added'
    /Users/justin/.rbenv/versions/3.3.0/lib/ruby/gems/3.3.0/gems/dotenv-3.1.0/lib/dotenv/diff.rb:47:in `any?'
    /Users/justin/.rbenv/versions/3.3.0/lib/ruby/gems/3.3.0/gems/dotenv-3.1.0/lib/dotenv.rb:79:in `restore'
    /Users/justin/.rbenv/versions/3.3.0/lib/ruby/gems/3.3.0/gems/dotenv-3.1.0/lib/dotenv/autorestore.rb:21:in `block (3 levels) in <main>'
    /Users/justin/.rbenv/versions/3.3.0/lib/ruby/gems/3.3.0/bundler/gems/rails-9e01d93547e2/activesupport/lib/active_support/callbacks.rb:407:in `instance_exec'
    /Users/justin/.rbenv/versions/3.3.0/lib/ruby/gems/3.3.0/bundler/gems/rails-9e01d93547e2/activesupport/lib/active_support/callbacks.rb:407:in `block in make_lambda'
    /Users/justin/.rbenv/versions/3.3.0/lib/ruby/gems/3.3.0/bundler/gems/rails-9e01d93547e2/activesupport/lib/active_support/callbacks.rb:208:in `call'
    /Users/justin/.rbenv/versions/3.3.0/lib/ruby/gems/3.3.0/bundler/gems/rails-9e01d93547e2/activesupport/lib/active_support/callbacks.rb:563:in `block in invoke_after'
    /Users/justin/.rbenv/versions/3.3.0/lib/ruby/gems/3.3.0/bundler/gems/rails-9e01d93547e2/activesupport/lib/active_support/callbacks.rb:563:in `each'
    /Users/justin/.rbenv/versions/3.3.0/lib/ruby/gems/3.3.0/bundler/gems/rails-9e01d93547e2/activesupport/lib/active_support/callbacks.rb:563:in `invoke_after'
    /Users/justin/.rbenv/versions/3.3.0/lib/ruby/gems/3.3.0/bundler/gems/rails-9e01d93547e2/activesupport/lib/active_support/callbacks.rb:111:in `run_callbacks'
    /Users/justin/.rbenv/versions/3.3.0/lib/ruby/gems/3.3.0/bundler/gems/rails-9e01d93547e2/activesupport/lib/active_support/testing/setup_and_teardown.rb:46:in `after_teardown'

1 runs, 0 assertions, 0 failures, 1 errors, 0 skips

The issue appears to be with the ActiveSupport::TestCase support, in the teardown:

# lib/dotenv/autorestore.rb:21
# Restore ENV after each test
      teardown do
        Dotenv.restore

Which calls:

# lib/dotenv.rb
def restore(env = @diff&.a, safe: Thread.current == Thread.main)
    diff = Dotenv::Diff.new(b: env)
    return unless diff.any?

But at this point env is nil. I can see that @diff is set by:

# lib/dotenv.rb:66
def save
    instrument(:save) do |payload|
      @diff = payload[:diff] = Dotenv::Diff.new
    end
  end

But the above instrument(:save) block is never called, so @diffis never set. Whenany?is then called on theDotenv::Diffobject that has a nilb` value:

# lib/dotenv/diff.rb:47
# Returns true if any keys were added, removed, or changed
    def any?
      [added, removed, changed].any?(&:any?)
    end

All three of those added, removed, and changed methods will raise, because b is nil and they all call either b.slice or b.keys.

I'm not familiar with how dotenv works, so I don't know if the issue is that save isn't getting called, or if there's a missing guard clause to make this all nil-safe

System configuration

dotenv version: 3.1.0

Rails version:

I'm on the current tip of rails/rails#main: rails/rails@68b20b6

Just verified it also occurs on 7.1.3.2

Ruby version:

ruby 3.3.0 (2023-12-25 revision 5124f9ac75) [arm64-darwin23]

[searls]

Ah, I think I figured out how to repro: this happens when the test raises (in my case, I had a typo in a model, so loading the environment in the test_helper raised). That error gets swallowed, though, (for the sake of minitest's reporter, I imagine) and dotenv ends up at the top of the backtrace.

Dropping a random raise in any autoloaded class will do the trick:

class User < ApplicationRecord
  raise
end

[KapilSachdev]

This was happening because of hotwired/turbo-rails#587 in my case.

[bkeepers]

@searls I'm still having issue reproducing. Where are you referencing the User model to reproduce the error?

# app/models/failwhale.rb
class Failwhale
  raise
end


# test/test_helper.rb
ENV["RAILS_ENV"] ||= "test"
require_relative "../config/environment"
require "rails/test_help"

# I tried HERE first
# Failwhale

module ActiveSupport
  class TestCase
    # Run tests in parallel with specified workers
    parallelize(workers: :number_of_processors)

    # Setup all fixtures in test/fixtures/*.yml for all tests in alphabetical order.
    fixtures :all

    # and HERE
    # Failwhale
  end
end


class MyTest < ActiveSupport::TestCase
  setup do
    # and HERE
    # Failwhale
  end

  # And HERE
  test "a test case" do
    Failwhale
  end
end

In all cases, the error got was:

❯ rails test
app/models/failwhale.rb:2:in `<class:Failwhale>': unhandled exception
	from app/models/failwhale.rb:1:in `<main>'