From ec03eb6fba7db37c1c74963a6ec4b37098146e1c Mon Sep 17 00:00:00 2001
From: Andy Clayton <andy@iso.io>
Date: Thu, 10 Mar 2022 09:50:32 -0600
Subject: [PATCH 1/2] restore 2.x config loading behavior

Attempt to restore 2.x config loading behavior where 1) per-model config blocks
only evaluate after all the models are loaded and associations are defined
while 2) initializer config block evaluates immediately so that routes are
configured correctly.

One remaining change compared to 2.x is RailsAdmin::Config#model no longer
returns the model when given a block. With the removal of LazyModel in e4ae669
it is tricky to both defer initialization and return the model class.

Fixes https://github.com/railsadminteam/rails_admin/issues/3490
---
 .rubocop.yml                                  |  2 +-
 lib/rails_admin.rb                            |  4 ++-
 lib/rails_admin/adapters/mongoid/extension.rb |  4 +--
 lib/rails_admin/config.rb                     | 32 +++++++++++++++----
 lib/rails_admin/engine.rb                     |  5 ---
 spec/rails_admin/config_spec.rb               | 24 ++++++++++++++
 6 files changed, 55 insertions(+), 16 deletions(-)

diff --git a/.rubocop.yml b/.rubocop.yml
index f9e7add9f9..812b176a02 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -118,7 +118,7 @@ Metrics/MethodLength:
   Max: 29 # TODO: Lower to 15
 
 Metrics/ModuleLength:
-  Max: 217 # TODO: Lower to 100
+  Max: 228 # TODO: Lower to 100
 
 Metrics/ParameterLists:
   Max: 8 # TODO: Lower to 4
diff --git a/lib/rails_admin.rb b/lib/rails_admin.rb
index 7f70d4d507..fee9e267d6 100644
--- a/lib/rails_admin.rb
+++ b/lib/rails_admin.rb
@@ -29,7 +29,9 @@ def self.config(entity = nil, &block)
     if entity
       RailsAdmin::Config.model(entity, &block)
     elsif block_given?
-      RailsAdmin::Config.apply(&block)
+      # Immediately evaluate non-model (initializer) config. It's needed to
+      # properly configure routes when there are custom actions.
+      yield RailsAdmin::Config
     else
       RailsAdmin::Config
     end
diff --git a/lib/rails_admin/adapters/mongoid/extension.rb b/lib/rails_admin/adapters/mongoid/extension.rb
index e669c693a5..3803525a24 100644
--- a/lib/rails_admin/adapters/mongoid/extension.rb
+++ b/lib/rails_admin/adapters/mongoid/extension.rb
@@ -11,9 +11,7 @@ module Extension
           self.nested_attributes_options = {}
           class << self
             def rails_admin(&block)
-              RailsAdmin.config do |config|
-                config.model(self, &block)
-              end
+              RailsAdmin.config(self, &block)
             end
 
             alias_method :accepts_nested_attributes_for_without_rails_admin, :accepts_nested_attributes_for
diff --git a/lib/rails_admin/config.rb b/lib/rails_admin/config.rb
index 531b6701b4..48c0426403 100644
--- a/lib/rails_admin/config.rb
+++ b/lib/rails_admin/config.rb
@@ -24,6 +24,7 @@ module Config
 
     # Variables to track initialization process
     @initialized = false
+    @initializing = false
     @deferred_blocks = []
 
     class << self
@@ -87,6 +88,9 @@ class << self
 
       # Finish initialization by executing deferred configuration blocks
       def initialize!
+        return if @initializing
+
+        @initializing = true
         @deferred_blocks.each { |block| block.call(self) }
         @deferred_blocks.clear
         @initialized = true
@@ -226,6 +230,7 @@ def default_search_operator=(operator)
 
       # pool of all found model names from the whole application
       def models_pool
+        initialize!
         (viable_models - excluded_models.collect(&:to_s)).uniq.sort
       end
 
@@ -238,7 +243,7 @@ def models_pool
       #
       # If a block is given it is evaluated in the context of configuration instance.
       #
-      # Returns given model's configuration
+      # Otherwise returns given model's configuration.
       #
       # @see RailsAdmin::Config.registry
       def model(entity, &block)
@@ -254,9 +259,24 @@ def model(entity, &block)
             entity.class.name.to_sym
           end
 
-        @registry[key] ||= RailsAdmin::Config::Model.new(entity)
-        @registry[key].instance_eval(&block) if block && @registry[key].abstract_model
-        @registry[key]
+        # When a block is provided defer evaluation until initialize so that:
+        #
+        # 1) performing configuration in the initializer does not attempt to
+        #    autoload model classes, and
+        # 2) model config blocks run after models are fully loaded and
+        #    associations are defined.
+        #
+        # Do not defer when called without a block as the model must be returned.
+        if block
+          RailsAdmin::Config.apply do
+            m = model(entity)
+            m.instance_eval(&block) if @registry[key].abstract_model
+          end
+          nil
+        else
+          initialize!
+          @registry[key] ||= RailsAdmin::Config::Model.new(entity)
+        end
       end
 
       def asset_source
@@ -318,6 +338,8 @@ def models
       #
       # @see RailsAdmin::Config.registry
       def reset
+        @initialized = @initializing = false
+        @deferred_blocks.clear
         @compact_show_view = true
         @browser_validations = true
         @authenticate = nil
@@ -356,10 +378,8 @@ def reset_model(model)
 
       # Perform reset, then load RailsAdmin initializer again
       def reload!
-        @initialized = false
         reset
         load RailsAdmin::Engine.config.initializer_path
-        initialize!
       end
 
       # Get all models that are configured as visible sorted by their weight and label.
diff --git a/lib/rails_admin/engine.rb b/lib/rails_admin/engine.rb
index 788071eff6..b462fb557d 100644
--- a/lib/rails_admin/engine.rb
+++ b/lib/rails_admin/engine.rb
@@ -68,11 +68,6 @@ class Engine < Rails::Engine
         ERROR
       end
 
-      RailsAdmin::Config.initialize!
-
-      # Force route reload, since it doesn't reflect RailsAdmin action configuration yet
-      app.reload_routes!
-
       RailsAdmin::Version.warn_with_js_version
     end
   end
diff --git a/spec/rails_admin/config_spec.rb b/spec/rails_admin/config_spec.rb
index 521515960c..bf1f27dd04 100644
--- a/spec/rails_admin/config_spec.rb
+++ b/spec/rails_admin/config_spec.rb
@@ -327,6 +327,24 @@ class TestController < ActionController::Base; end
       end
     end
 
+    context 'when a block is not provided' do
+      let(:model) { described_class.model(Team) }
+      it 'returns the model config' do
+        expect(model).to be_a(RailsAdmin::Config::Model)
+      end
+    end
+
+    context 'when a block is provided' do
+      let(:model) do
+        described_class.model(Team) do
+          field :fans
+        end
+      end
+      it 'does not return the model config' do
+        expect(model).to be_nil
+      end
+    end
+
     context 'when model expanded' do
       before do
         described_class.model(Team) do
@@ -387,6 +405,7 @@ class TestController < ActionController::Base; end
       end
     end
     before { RailsAdmin::Config.instance_variable_set(:@initialized, false) }
+    before { RailsAdmin::Config.instance_variable_set(:@initializing, false) }
     after do
       RailsAdmin::Config.instance_variable_set(:@initialized, true)
       RailsAdmin::Config.instance_variable_set(:@deferred_blocks, [])
@@ -445,6 +464,11 @@ class TestController < ActionController::Base; end
       expect(RailsAdmin::Config.model(Team).fields.find { |f| f.name == :color }.type).to eq :color
     end
 
+    it 'does not immediately apply model configuration' do
+      expect(RailsAdmin::Config).not_to receive(:initialize!)
+      RailsAdmin::Config.reload!
+    end
+
     it "applies the initializer's configuration first, then models' configurations" do
       # simulate the situation that Team model is loaded in the middle of processing RailsAdmin initializer
       allow_any_instance_of(RailsAdmin::Config::Model).to receive(:include_all_fields).and_wrap_original do |method|

From e2ec3b9f3ecacae217709a5c26d50663641715ad Mon Sep 17 00:00:00 2001
From: Andy Clayton <andy@iso.io>
Date: Mon, 14 Mar 2022 14:18:52 -0500
Subject: [PATCH 2/2] maintain 3.x deferred initializer block config

In 3.x the initializer config blocks are intentionally deferred to allow
referencing model classes without quoting. Here is a first pass at keeping that
behavior on top of ec03eb6f. It could probably use a little cleanup but here's
an idea of an approach for feedback.

See
https://github.com/railsadminteam/rails_admin/pull/3492#issuecomment-1064915362
for details.
---
 .rubocop.yml                                  |  4 +-
 lib/rails_admin.rb                            |  4 +-
 lib/rails_admin/config.rb                     | 64 +++++++++++++------
 lib/rails_admin/engine.rb                     |  5 ++
 .../config/initializers/rails_admin.rb        |  2 +-
 spec/rails_admin/config_spec.rb               | 29 +++++----
 spec/spec_helper.rb                           |  1 +
 7 files changed, 71 insertions(+), 38 deletions(-)

diff --git a/.rubocop.yml b/.rubocop.yml
index 812b176a02..030bae93ff 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -115,10 +115,10 @@ Metrics/CyclomaticComplexity:
 
 Metrics/MethodLength:
   CountComments: false
-  Max: 29 # TODO: Lower to 15
+  Max: 30 # TODO: Lower to 15
 
 Metrics/ModuleLength:
-  Max: 228 # TODO: Lower to 100
+  Max: 248 # TODO: Lower to 100
 
 Metrics/ParameterLists:
   Max: 8 # TODO: Lower to 4
diff --git a/lib/rails_admin.rb b/lib/rails_admin.rb
index fee9e267d6..f58f254ade 100644
--- a/lib/rails_admin.rb
+++ b/lib/rails_admin.rb
@@ -29,9 +29,7 @@ def self.config(entity = nil, &block)
     if entity
       RailsAdmin::Config.model(entity, &block)
     elsif block_given?
-      # Immediately evaluate non-model (initializer) config. It's needed to
-      # properly configure routes when there are custom actions.
-      yield RailsAdmin::Config
+      RailsAdmin::Config.apply_core(&block)
     else
       RailsAdmin::Config
     end
diff --git a/lib/rails_admin/config.rb b/lib/rails_admin/config.rb
index 48c0426403..431c7eeace 100644
--- a/lib/rails_admin/config.rb
+++ b/lib/rails_admin/config.rb
@@ -23,9 +23,12 @@ module Config
     DEFAULT_CURRENT_USER = proc {}
 
     # Variables to track initialization process
-    @initialized = false
-    @initializing = false
-    @deferred_blocks = []
+    @initialized_core = false
+    @initializing_core = false
+    @deferred_core_blocks = []
+    @initialized_models = false
+    @initializing_models = false
+    @deferred_model_blocks = []
 
     class << self
       # Application title, can be an array of two elements
@@ -86,22 +89,42 @@ class << self
       # Set where RailsAdmin fetches JS/CSS from, defaults to :sprockets
       attr_writer :asset_source
 
-      # Finish initialization by executing deferred configuration blocks
-      def initialize!
-        return if @initializing
+      # Finish initialization by executing deferred non-model configuration blocks
+      def initialize_core!
+        return if @initializing_core
 
-        @initializing = true
-        @deferred_blocks.each { |block| block.call(self) }
-        @deferred_blocks.clear
-        @initialized = true
+        @initializing_core = true
+        @deferred_core_blocks.each { |block| block.call(self) }
+        @deferred_core_blocks.clear
+        @initialized_core = true
       end
 
-      # Evaluate the given block either immediately or lazily, based on initialization status.
-      def apply(&block)
-        if @initialized
+      # Evaluate the given non-model block either immediately or lazily, based on initialization status.
+      def apply_core(&block)
+        if @initialized_core
           yield(self)
         else
-          @deferred_blocks << block
+          @deferred_core_blocks << block
+        end
+      end
+
+      # Finish initialization by executing deferred model configuration blocks
+      def initialize_models!
+        return if @initializing_models
+
+        initialize_core!
+        @initializing_models = true
+        @deferred_model_blocks.each { |block| block.call(self) }
+        @deferred_model_blocks.clear
+        @initialized_models = true
+      end
+
+      # Evaluate the given model block either immediately or lazily, based on initialization status.
+      def apply_model(&block)
+        if @initialized_models
+          yield(self)
+        else
+          @deferred_model_blocks << block
         end
       end
 
@@ -230,7 +253,7 @@ def default_search_operator=(operator)
 
       # pool of all found model names from the whole application
       def models_pool
-        initialize!
+        initialize_models!
         (viable_models - excluded_models.collect(&:to_s)).uniq.sort
       end
 
@@ -268,13 +291,13 @@ def model(entity, &block)
         #
         # Do not defer when called without a block as the model must be returned.
         if block
-          RailsAdmin::Config.apply do
+          RailsAdmin::Config.apply_model do
             m = model(entity)
             m.instance_eval(&block) if @registry[key].abstract_model
           end
           nil
         else
-          initialize!
+          initialize_models!
           @registry[key] ||= RailsAdmin::Config::Model.new(entity)
         end
       end
@@ -338,8 +361,10 @@ def models
       #
       # @see RailsAdmin::Config.registry
       def reset
-        @initialized = @initializing = false
-        @deferred_blocks.clear
+        @initialized_core = @initializing_core = false
+        @deferred_core_blocks.clear
+        @initialized_models = @initializing_models = false
+        @deferred_model_blocks.clear
         @compact_show_view = true
         @browser_validations = true
         @authenticate = nil
@@ -380,6 +405,7 @@ def reset_model(model)
       def reload!
         reset
         load RailsAdmin::Engine.config.initializer_path
+        initialize_core!
       end
 
       # Get all models that are configured as visible sorted by their weight and label.
diff --git a/lib/rails_admin/engine.rb b/lib/rails_admin/engine.rb
index b462fb557d..ef3042da21 100644
--- a/lib/rails_admin/engine.rb
+++ b/lib/rails_admin/engine.rb
@@ -68,6 +68,11 @@ class Engine < Rails::Engine
         ERROR
       end
 
+      RailsAdmin::Config.initialize_core!
+
+      # Force route reload, since it doesn't reflect RailsAdmin action configuration yet
+      app.reload_routes!
+
       RailsAdmin::Version.warn_with_js_version
     end
   end
diff --git a/spec/dummy_app/config/initializers/rails_admin.rb b/spec/dummy_app/config/initializers/rails_admin.rb
index 6f3d9b9ade..6f81505b39 100644
--- a/spec/dummy_app/config/initializers/rails_admin.rb
+++ b/spec/dummy_app/config/initializers/rails_admin.rb
@@ -2,7 +2,7 @@
 
 RailsAdmin.config do |c|
   c.asset_source = CI_ASSET
-  c.model 'Team' do
+  c.model Team do
     include_all_fields
     field :color, :color
   end
diff --git a/spec/rails_admin/config_spec.rb b/spec/rails_admin/config_spec.rb
index bf1f27dd04..6fadce48e3 100644
--- a/spec/rails_admin/config_spec.rb
+++ b/spec/rails_admin/config_spec.rb
@@ -395,8 +395,8 @@ class TestController < ActionController::Base; end
     end
   end
 
-  describe '.apply' do
-    subject { RailsAdmin::Config.apply(&block) }
+  describe '.apply_core' do
+    subject { RailsAdmin::Config.apply_core(&block) }
     let(:block) do
       proc do |config|
         config.model Team do
@@ -404,32 +404,35 @@ class TestController < ActionController::Base; end
         end
       end
     end
-    before { RailsAdmin::Config.instance_variable_set(:@initialized, false) }
-    before { RailsAdmin::Config.instance_variable_set(:@initializing, false) }
-    after do
-      RailsAdmin::Config.instance_variable_set(:@initialized, true)
-      RailsAdmin::Config.instance_variable_set(:@deferred_blocks, [])
-    end
+    after { RailsAdmin::Config.reset }
 
     it "doesn't evaluate the block immediately" do
       expect_any_instance_of(RailsAdmin::Config::Model).not_to receive(:register_instance_option)
       subject
     end
 
-    it 'evaluates block when initialize! is finished' do
+    it "doesn't evaluate the block when initialize_core! is finished" do
+      expect_any_instance_of(RailsAdmin::Config::Model).not_to receive(:register_instance_option).with('parameter')
+      subject
+      RailsAdmin::Config.initialize_core!
+    end
+
+    it 'evaluates block when initialize_models! is finished' do
       expect_any_instance_of(RailsAdmin::Config::Model).to receive(:register_instance_option).with('parameter')
       subject
-      RailsAdmin::Config.initialize!
+      RailsAdmin::Config.initialize_models!
     end
 
     it 'evaluates config block only once' do
       expect_any_instance_of(RailsAdmin::Config::Model).to receive(:register_instance_option).once.with('parameter')
       subject
-      RailsAdmin::Config.initialize!
-      RailsAdmin::Config.initialize!
+      RailsAdmin::Config.initialize_models!
+      RailsAdmin::Config.initialize_models!
     end
 
     context 'with a non-existent class' do
+      before { RailsAdmin::Config.reset }
+
       let(:block) do
         proc do |config|
           config.model UnknownClass do
@@ -465,7 +468,7 @@ class TestController < ActionController::Base; end
     end
 
     it 'does not immediately apply model configuration' do
-      expect(RailsAdmin::Config).not_to receive(:initialize!)
+      expect(RailsAdmin::Config).not_to receive(:initialize_models!)
       RailsAdmin::Config.reload!
     end
 
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index e4d9fa8feb..e728bc5d3d 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -93,6 +93,7 @@
     DatabaseCleaner.start
     RailsAdmin::Config.reset
     RailsAdmin::Config.asset_source = CI_ASSET
+    RailsAdmin::Config.initialize_core!
   end
 
   config.after(:each) do