Schema dumping support for PostgreSQL oid type

Closes #27980

8 files changed, 33 insertions, 13 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index 49d6324a52..8e1ea7d023 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,4 +1,4 @@
-*   PostgreSQL: schema dumping support for PostgreSQL interval type.
+*   PostgreSQL: schema dumping support for interval and OID columns.
 
     *Ryuta Kamizono*
 
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid.rb
index 0e526f6201..4098250f3e 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid.rb
@@ -11,6 +11,7 @@ require "active_record/connection_adapters/postgresql/oid/inet"
 require "active_record/connection_adapters/postgresql/oid/json"
 require "active_record/connection_adapters/postgresql/oid/jsonb"
 require "active_record/connection_adapters/postgresql/oid/money"
+require "active_record/connection_adapters/postgresql/oid/oid"
 require "active_record/connection_adapters/postgresql/oid/point"
 require "active_record/connection_adapters/postgresql/oid/legacy_point"
 require "active_record/connection_adapters/postgresql/oid/range"
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/oid.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/oid.rb
new file mode 100644
index 0000000000..9c2ac08b30
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/oid.rb
@@ -0,0 +1,13 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Oid < Type::Integer # :nodoc:
+          def type
+            :oid
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb
index 372958b9be..11ea1e5144 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb
@@ -124,6 +124,10 @@ module ActiveRecord
           args.each { |name| column(name, :numrange, options) }
         end
 
+        def oid(*args, **options)
+          args.each { |name| column(name, :oid, options) }
+        end
+
         def point(*args, **options)
           args.each { |name| column(name, :point, options) }
         end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 89d595eef5..5ce61183cd 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -110,6 +110,7 @@ module ActiveRecord
         bit_varying: { name: "bit varying" },
         money:       { name: "money" },
         interval:    { name: "interval" },
+        oid:         { name: "oid" },
       }
 
       OID = PostgreSQL::OID #:nodoc:
@@ -452,7 +453,7 @@ module ActiveRecord
           register_class_with_limit m, "int2", Type::Integer
           register_class_with_limit m, "int4", Type::Integer
           register_class_with_limit m, "int8", Type::Integer
-          m.alias_type "oid", "int2"
+          m.register_type "oid", OID::Oid.new
           m.register_type "float4", Type::Float.new
           m.alias_type "float8", "float4"
           m.register_type "text", Type::Text.new
diff --git a/activerecord/test/cases/adapters/postgresql/datatype_test.rb b/activerecord/test/cases/adapters/postgresql/datatype_test.rb
index dc17a715e8..0725fde5ae 100644
--- a/activerecord/test/cases/adapters/postgresql/datatype_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/datatype_test.rb
@@ -33,7 +33,7 @@ class PostgresqlDataTypeTest < ActiveRecord::PostgreSQLTestCase
   end
 
   def test_data_type_of_oid_types
-    assert_equal :integer, @first_oid.column_for_attribute(:obj_id).type
+    assert_equal :oid, @first_oid.column_for_attribute(:obj_id).type
   end
 
   def test_time_values
diff --git a/activerecord/test/cases/schema_dumper_test.rb b/activerecord/test/cases/schema_dumper_test.rb
index ea860ef5de..68193af16c 100644
--- a/activerecord/test/cases/schema_dumper_test.rb
+++ b/activerecord/test/cases/schema_dumper_test.rb
@@ -286,6 +286,11 @@ class SchemaDumperTest < ActiveRecord::TestCase
       assert_match %r{t\.interval\s+"scaled_time_interval",\s+precision: 6$}, output
     end
 
+    def test_schema_dump_oid_type
+      output = dump_table_schema "postgresql_oids"
+      assert_match %r{t\.oid\s+"obj_id"$}, output
+    end
+
     if ActiveRecord::Base.connection.supports_extensions?
       def test_schema_dump_includes_extensions
         connection = ActiveRecord::Base.connection
diff --git a/activerecord/test/schema/postgresql_specific_schema.rb b/activerecord/test/schema/postgresql_specific_schema.rb
index a390a76a16..d6cc4e2d6e 100644
--- a/activerecord/test/schema/postgresql_specific_schema.rb
+++ b/activerecord/test/schema/postgresql_specific_schema.rb
@@ -33,11 +33,14 @@ ActiveRecord::Schema.define do
     t.interval :scaled_time_interval, precision: 6
   end
 
-  %w(postgresql_oids postgresql_timestamp_with_zones
-      postgresql_partitioned_table postgresql_partitioned_table_parent).each do |table_name|
-    drop_table table_name, if_exists: true
+  create_table :postgresql_oids, force: true do |t|
+    t.oid :obj_id
   end
 
+  drop_table 'postgresql_timestamp_with_zones', if_exists: true
+  drop_table 'postgresql_partitioned_table', if_exists: true
+  drop_table 'postgresql_partitioned_table_parent', if_exists: true
+
   execute "DROP SEQUENCE IF EXISTS companies_nonstd_seq CASCADE"
   execute "CREATE SEQUENCE companies_nonstd_seq START 101 OWNED BY companies.id"
   execute "ALTER TABLE companies ALTER COLUMN id SET DEFAULT nextval('companies_nonstd_seq')"
@@ -50,13 +53,6 @@ ActiveRecord::Schema.define do
   end
 
   execute <<_SQL
-  CREATE TABLE postgresql_oids (
-    id SERIAL PRIMARY KEY,
-    obj_id OID
-  );
-_SQL
-
-  execute <<_SQL
   CREATE TABLE postgresql_timestamp_with_zones (
     id SERIAL PRIMARY KEY,
     time TIMESTAMP WITH TIME ZONE