While trying to fix#16433, we made the middleware deletions always
happen at the end. While this works for the case of deleting the
Rack::Runtime middleware, it makes operations like the following
misbehave.
```ruby
gem "bundler", "< 1.16"
begin
require "bundler/inline"
rescue LoadError => e
$stderr.puts "Bundler version 1.10 or later is required. Please update your Bundler"
raise e
end
gemfile(true) do
source "https://rubygems.org"
git_source(:github) { |repo| "https://github.com/#{repo}.git" }
gem "rails", github: "rails/rails"
end
require "action_controller/railtie"
class TestApp < Rails::Application
config.root = __dir__
secrets.secret_key_base = "secret_key_base"
config.logger = Logger.new($stdout)
Rails.logger = config.logger
middleware.insert_after ActionDispatch::Session::CookieStore, ::Rails::Rack::Logger, config.log_tags
middleware.delete ::Rails::Rack::Logger
end
require "minitest/autorun"
require "rack/test"
class BugTest < Minitest::Test
include Rack::Test::Methods
def test_returns_success
get "/"
assert last_response.ok?
end
private
def app
Rails.application
end
end
```
In the case ☝️ the ::Rails::Rack::Logger would be deleted instead of
moved, because the order of middleware stack building execution will be:
```ruby
[:insert, ActionDispatch::Session::CookieStore, [::Rails::Rack::Logger]]
[:delete, ::Rails::Rack::Logger, [config.log_tags]]
```
This is pretty surprising and hard to reason about behaviour, unless you
go spelunking into the Rails configuration code.
I have a few solutions in mind and all of them have their drawbacks.
1. Introduce a `Rails::Configuration::MiddlewareStackProxy#delete!` that
delays the deleted operations. This will make `#delete` to be executed
in order. The drawback here is backwards incompatible behavior and a new
public method.
2. Just revert to the old operations. This won't allow people to delete
the `Rack::Runtime` middleware.
3. Legitimize the middleware moving with the new `#move_after` and
`#move_before` methods. This does not breaks any backwards
compatibility, but includes 2 new methods to the middleware stack.
I have implemented `3.` in this pull request.
Happy holidays! 🎄
40fc1651ad