auto_increment is the only column to be returned after insert for D…

…Bs with no `RETURNING` support

c2c861f wasn't a sufficient fix for tables that
have more than just one auto populated column but the database doesn't support `RETURNING` statement.

This commit ensures that mysql adapters will only consider `auto_increment` columns to be
returned after insert which also implies that only one column can be returned after insert.

activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb

@@ -174,6 +174,10 @@ def supports_insert_returning?
         mariadb? && database_version >= "10.5.0"
       end
 
+      def return_value_after_insert?(column) # :nodoc:
+        supports_insert_returning? ? column.auto_populated? : column.auto_increment?
+      end
+
       def get_advisory_lock(lock_name, timeout = 0) # :nodoc:
         query_value("SELECT GET_LOCK(#{quote(lock_name.to_s)}, #{timeout})") == 1
       end

activerecord/test/cases/persistence_test.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require "cases/helper"
+require "models/auto_id"
 require "models/aircraft"
 require "models/dashboard"
 require "models/clothing_item"
@@ -38,6 +39,22 @@ def test_populates_non_primary_key_autoincremented_column
     assert_not_nil topic.attributes["id"]
   end
 
+  def test_populates_autoincremented_id_pk_regardless_of_its_position_in_columns_list
+    auto_populated_column_names = AutoId.columns.select(&:auto_populated?).map(&:name)
+
+    # It's important we test a scenario where tables has more than one auto populated column
+    # and the first column is not the primary key. Otherwise it will be a regular test not asserting this special case.
+    assert auto_populated_column_names.size > 1
+    assert_not_equal AutoId.primary_key, auto_populated_column_names.first
+
+    record = AutoId.create!
+    last_id = AutoId.last.id
+
+    assert_not_nil last_id
+    assert last_id > 0
+    assert_equal last_id, record.id
+  end
+
   def test_populates_non_primary_key_autoincremented_column_for_a_cpk_model
     order = Cpk::Order.create(shop_id: 111_222)
 

activerecord/test/schema/schema.rb

@@ -105,8 +105,14 @@
   end
 
   create_table :auto_id_tests, force: true, id: false do |t|
-    t.primary_key :auto_id
     t.integer     :value
+    default_func = if ActiveRecord::TestCase.current_adapter?(:SQLite3Adapter)
+      -> { "(CAST(40 AS INTEGER) + CAST(2 AS INTEGER))" }
+    else
+      -> { "(40 + 2)" }
+    end
+    t.integer     :default_func_value, default: default_func
+    t.primary_key :auto_id
   end
 
   create_table :binaries, force: true do |t|