Merge pull request #51339 from gjtorikian/enable-n_plus_one_only-toggling

Allow one to set `strict_loading_mode` globally

activerecord/CHANGELOG.md

@@ -1,3 +1,9 @@
+*   Allow to configure `strict_loading_mode` globally or within a model.
+
+    Defaults to `:all`, can be changed to `:n_plus_one_only`.
+
+    *Garen Torikian*
+
 *   Add `ActiveRecord::Relation#readonly?`.
 
     Reflects if the relation has been marked as readonly.

activerecord/lib/active_record/core.rb

@@ -89,6 +89,7 @@ module ActiveRecord
       class_attribute :belongs_to_required_by_default, instance_accessor: false
 
       class_attribute :strict_loading_by_default, instance_accessor: false, default: false
+      class_attribute :strict_loading_mode, instance_accessor: false, default: :all
 
       class_attribute :has_many_inversing, instance_accessor: false, default: false
 
@@ -784,7 +785,7 @@ module ActiveRecord
 
         @primary_key         = klass.primary_key
         @strict_loading      = klass.strict_loading_by_default
-        @strict_loading_mode = :all
+        @strict_loading_mode = klass.strict_loading_mode
 
         klass.define_attribute_methods
       end

activerecord/test/cases/strict_loading_test.rb

@@ -98,6 +98,20 @@ class StrictLoadingTest < ActiveRecord::TestCase
     end
   end
 
+  def test_default_mode_is_all
+    developer = Developer.first
+    assert_predicate developer, :strict_loading_all?
+  end
+
+  def test_default_mode_can_be_changed_globally
+    developer = Class.new(ActiveRecord::Base) do
+      self.strict_loading_mode = :n_plus_one_only
+      self.table_name = "developers"
+    end.new
+
+    assert_predicate developer, :strict_loading_n_plus_one_only?
+  end
+
   def test_strict_loading
     Developer.all.each { |d| assert_not d.strict_loading? }
     Developer.strict_loading.each { |d| assert_predicate d, :strict_loading? }

guides/source/configuring.md

@@ -1284,6 +1284,12 @@ changed to `:log` to send violations to the logger instead of raising.
 Is a boolean value that either enables or disables strict_loading mode by
 default. Defaults to `false`.
 
+#### `config.active_record.strict_loading_mode`
+
+Sets the mode in which strict loading is reported. Defaults to `:all`. It can be
+changed to `:n_plus_one_only` to only report when loading associations that will
+lead to an N + 1 query.
+
 #### `config.active_record.warn_on_records_fetched_greater_than`
 
 Allows setting a warning threshold for query result size. If the number of