Merge pull request rails#27561 from fishbrain/count-all-in-has-many-a…

…ssociation

Use `count(:all)` in HasManyAssociation#count_records

activerecord/CHANGELOG.md

@@ -1,3 +1,8 @@
+*   Use `count(:all)` in `HasManyAssociation#count_records` to prevent invalid
+    SQL queries for association counting.
+
+    *Klas Eskilson*
+
 *   Fix to invoke callbacks when using `update_attribute`.
 
     *Mike Busch*

activerecord/lib/active_record/associations/has_many_association.rb

@@ -61,7 +61,7 @@ def count_records
           count = if reflection.has_cached_counter?
             owner._read_attribute(reflection.counter_cache_column).to_i
           else
-            scope.count
+            scope.count(:all)
           end
 
           # If there's nothing in the database and @target has no new records

activerecord/test/cases/associations/has_many_associations_test.rb

@@ -2502,6 +2502,14 @@ def self.name
     assert_equal [first_bulb, second_bulb], car.bulbs
   end
 
+  test "association size calculation works with default scoped selects when not previously fetched" do
+    firm = Firm.create!(name: "Firm")
+    5.times { firm.developers_with_select << Developer.create!(name: "Developer") }
+
+    same_firm = Firm.find(firm.id)
+    assert_equal 5, same_firm.developers_with_select.size
+  end
+
   test "prevent double insertion of new object when the parent association loaded in the after save callback" do
     reset_callbacks(:save, Bulb) do
       Bulb.after_save { |record| record.car.bulbs.load }

activerecord/test/models/company.rb

@@ -85,6 +85,8 @@ class Firm < Company
 
   has_many :association_with_references, -> { references(:foo) }, class_name: "Client"
 
+  has_many :developers_with_select, -> { select("id, name, first_name") }, class_name: "Developer"
+
   has_one :lead_developer, class_name: "Developer"
   has_many :projects