Fix copying column background migration to work with primary keys add…

…ed via `initialize_column_type_change`

Fixes #52.

CHANGELOG.md

@@ -1,5 +1,7 @@
 ## master (unreleased)
 
+- Fix copying column background migration to work with primary keys added via `initialize_column_type_change`
+
 ## 0.16.0 (2024-03-28)
 
 - Add support for asynchronous creation/removal of indexes

lib/online_migrations/background_migrations/copy_column.rb

@@ -25,10 +25,7 @@ def initialize(table_name, copy_from, copy_to, model_name = nil, type_cast_funct
       end
 
       def relation
-        model
-          .unscoped
-          .where(copy_to.index_with(nil))
-          .where.not(copy_from.index_with(nil))
+        model.unscoped
       end
 
       def process_batch(relation)

test/background_migrations/copy_column_test.rb

@@ -33,6 +33,19 @@ def test_relation
       assert_kind_of ActiveRecord::Relation, m.relation
     end
 
+    def test_relation_considers_all_rows
+      Project.update_all(id_for_type_change: 0) # is typically set via initialize_column_type_change
+
+      m = OnlineMigrations::BackgroundMigrations::CopyColumn.new(:projects, ["id"], ["id_for_type_change"])
+      m.process_batch(m.relation)
+
+      @project1.reload
+      @project2.reload
+
+      assert_equal @project1.id, @project1.id_for_type_change
+      assert_equal @project2.id, @project2.id_for_type_change
+    end
+
     def test_process_batch
       m = OnlineMigrations::BackgroundMigrations::CopyColumn.new(:projects, ["id"], ["id_for_type_change"], Project.name)
       m.process_batch(m.relation)