Hello, thanks for this PR, it looks like a good change

Can you please:

• Rebase on master, there is a merge conflict
• Add a spec
• Provide more information like:
  • is this trying to solve an existing bug? If it is, any chance to better describe the bug?
  • is this a performance-only change

@tagliala thx for the review, addressed all points.

Provide more information like

This is trying to improve dev-local performance of using activeadmin with autoloading enabled; while resources get eager-loaded as part of the route injection, it doesn't really need to load the resources until the page is loaded.

This is trying to improve dev-local performance of using activeadmin with autoloading enabled; while resources get eager-loaded as part of the route injection, it doesn't really need to load the resources until the page is loaded.

Thanks. I did try to measure the performance gain, but I'm afraid I did not succeed (Rails 8.1 / Ruby 3.4 / Apple Silicon M1 Pro). I've tried to enable eager_load, and switch to classic mode instead of zeitwerk, but unfortunately I cannot see improvements or changes. Maybe it depends on the number of models? Any chance to provide a demo application on github to see improvements? Do you want me to create

PS: is this also related to #8782 ?

Also involving @javierjulio and @mgrunberg . This is like the rails change in class_name. I think this is somehow related to https://www.rubydoc.info/gems/rubocop-rails/RuboCop/Cop/Rails/ReflectionClassName rubocop/rubocop#6704

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.08%. Comparing base (0996891) to head (c7651ba).
⚠️ Report is 1 commits behind head on master.

@@           Coverage Diff           @@
##           master    #8848   +/-   ##
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  Coverage   99.08%   99.08%           
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  Files         139      139           
  Lines        4046     4046           
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  Hits         4009     4009           
  Misses         37       37           

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It's highly dependent on the size of the application and what you're doing at boot time. I've enabled this in our app as a monkeypatch, and the overall gains from reenabling autoloading (not only including activeadmin changes) amounted to ~10s saved when opening a console / running a spec touching 1-3 models.

And I can confirm it's related to what you linked.

@HoneyryderChuck thanks

I really would have the ability to test this by myself. I've tried against a different application with more models without success, I do not see benefits. Any chance to provide information about the Rails version used, the ruby version, some kind of time rspec ... commands to try?

Or maybe to edit https://github.com/activeadmin/demo.activeadmin.info to demonstrate the improvement

And I can confirm it's related to what you linked.

Is this change going to make #8782 unnecessary? Or, if both approaches are used, is this going to boost the performance even more?

@tagliala sorry haven't had the time to go back to this, as providing this minimal change is less overhead than providing a full blown app which measures the impact. I honestly believe that this is only noticeable in really big applications with convoluted boot time model logic, so the mileage always varies, and a reproduction will be of marginal value.

@tagliala from what you shared in Slack, the change makes sense and I think should be safe enough. Let's move the test case since as you shown we already have a spec for namespace registration. Thank you.

@javierjulio I've AI-generated a script to create thousands of models, and I'm still not able to replicate or see differences in loading time.

I've tested with 1k models

I've tested both config.eager_load values in development without seeing any difference when used with or without strings

I'm using demo.activeadmin.com as a base application on Apple Silicon M1 Pro.

The "solution" seems trivial, but it would be good to be able to understand the correct issue here.

Maybe it is a different version of Ruby or Rails? Classic and not zeitwerk mode?

Script:

#!/usr/bin/env ruby

require "fileutils"
require "active_support/inflector"

# CONFIGURABLE:
MODEL_PREFIX = "ExampleModel" # hardcoded for demo, could make configurable
MODEL_DIR = "app/models"
ADMIN_DIR = "app/admin"
MIGRATION_DIR = "db/migrate"

def usage
  puts "Usage: #{$0} <number_of_models>"
  exit 1
end

unless ARGV.size == 1 && ARGV[0] =~ /^\d+$/
  usage
end

num_models = ARGV[0].to_i
raise "Number must be > 0" if num_models < 1

models = (1..num_models).map { |i| "#{MODEL_PREFIX}#{i}" }

# 1. Remove previous models and active admin files for these models
models.each do |model|
  model_file = File.join(MODEL_DIR, "#{model.underscore}.rb")
  File.delete(model_file) if File.exist?(model_file)

  admin_file = File.join(ADMIN_DIR, "#{model.underscore}.rb")
  File.delete(admin_file) if File.exist?(admin_file)
end

# 2. Generate and run a migration to drop all the tables for these models
drop_migration_name = "drop_example_model_tables_#{Time.now.strftime('%Y%m%d%H%M%S')}"
drop_migration_file = File.join(MIGRATION_DIR, "#{Time.now.strftime('%Y%m%d%H%M%S')}_#{drop_migration_name}.rb")

drop_migration_content = <<~RUBY
  class #{drop_migration_name.camelize} < ActiveRecord::Migration[6.1]
    def change
      #{models.map { |model|
        "drop_table :#{model.underscore.pluralize} if table_exists?(:#{model.underscore.pluralize})"
      }.join("\n      ")}
    end
  end
RUBY

File.write(drop_migration_file, drop_migration_content)
puts "Generated migration to drop previous tables: #{drop_migration_file}"
system("bin/rails db:migrate") # runs the drop migration

# Remove the drop migration file after use (optional for idempotency)
File.delete(drop_migration_file) if File.exist?(drop_migration_file)

# 3. Generate model files
models.each do |model|
  model_file = File.join(MODEL_DIR, "#{model.underscore}.rb")
  File.write(model_file, <<~RUBY)
    class #{model} < ApplicationRecord
    end
  RUBY
  puts "Created model #{model_file}"
end

# 4. Generate migration to create tables
create_migration_name = "create_example_model_tables_#{Time.now.strftime('%Y%m%d%H%M%S')}"
create_migration_file = File.join(MIGRATION_DIR, "#{Time.now.strftime('%Y%m%d%H%M%S')}_#{create_migration_name}.rb")

create_migration_content = <<~RUBY
  class #{create_migration_name.camelize} < ActiveRecord::Migration[6.1]
    def change
      #{models.map { |model|
        <<~TABLE
          create_table :#{model.underscore.pluralize} do |t|
            t.string :name
            t.timestamps
          end
        TABLE
      }.join("\n      ")}
    end
  end
RUBY

File.write(create_migration_file, create_migration_content)
puts "Generated migration to create tables: #{create_migration_file}"
system("bin/rails db:migrate") # runs the create migration

# 5. Create ActiveAdmin config files
models.each do |model|
  admin_file = File.join(ADMIN_DIR, "#{model.underscore}.rb")
  File.write(admin_file, <<~RUBY)
    # frozen_string_literal: true

    ActiveAdmin.register #{model} do
    end
  RUBY
  puts "Created ActiveAdmin config: #{admin_file}"
end

puts "Done. Idempotent models and tables created for: #{models.join(', ')}"

1k models, Eager load: false, non-string

$ time rails runner 'puts "ok"'
ok

real	0m1.025s
user	0m0.733s
sys	0m0.286s

1k models, Eager load: false, strings

$ time rails runner 'puts "ok"'
ok

real	0m1.052s
user	0m0.733s
sys	0m0.312s