rename_table renames primary key index name

Formerly, `rename_table` only renamed primary key index name if the
column's data type was sequential (serial, etc in PostgreSQL). The
problem with that is tables whose primary keys had other data types
(e.g. UUID) maintained the old primary key name. So for example,
if the `cats` table has a UUID primary key, and the table is renamed to
`felines`, the primary key index will still be called `cats_pkey`
instead of `felines_pkey`. This PR corrects it.

activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb

@@ -377,14 +377,15 @@ module ActiveRecord
           clear_cache!
           execute "ALTER TABLE #{quote_table_name(table_name)} RENAME TO #{quote_table_name(new_name)}"
           pk, seq = pk_and_sequence_for(new_name)
-          if seq && seq.identifier == "#{table_name}_#{pk}_seq"
-            new_seq = "#{new_name}_#{pk}_seq"
+          if pk
             idx = "#{table_name}_pkey"
             new_idx = "#{new_name}_pkey"
-            execute "ALTER TABLE #{seq.quoted} RENAME TO #{quote_table_name(new_seq)}"
             execute "ALTER INDEX #{quote_table_name(idx)} RENAME TO #{quote_table_name(new_idx)}"
+            if seq && seq.identifier == "#{table_name}_#{pk}_seq"
+              new_seq = "#{new_name}_#{pk}_seq"
+              execute "ALTER TABLE #{seq.quoted} RENAME TO #{quote_table_name(new_seq)}"
+            end
           end
-
           rename_table_indexes(table_name, new_name)
         end
 

activerecord/test/cases/migration/rename_table_test.rb

@@ -79,10 +79,33 @@ module ActiveRecord
           assert_equal ConnectionAdapters::PostgreSQL::Name.new("public", "octopi_#{pk}_seq"), seq
         end
 
+        def test_renaming_table_renames_primary_key
+          connection.create_table :cats, id: :uuid, default: "uuid_generate_v4()"
+          rename_table :cats, :felines
+
+          assert connection.table_exists? :felines
+          refute connection.table_exists? :cats
+
+          primary_key_name = connection.select_values(<<-SQL.strip_heredoc, "SCHEMA")[0]
+            SELECT c.relname
+              FROM pg_class c
+              JOIN pg_index i
+                ON c.oid = i.indexrelid
+             WHERE i.indisprimary
+               AND i.indrelid = 'felines'::regclass
+          SQL
+
+          assert_equal "felines_pkey", primary_key_name
+        ensure
+          connection.drop_table :cats, if_exists: true
+          connection.drop_table :felines, if_exists: true
+        end
+
         def test_renaming_table_doesnt_attempt_to_rename_non_existent_sequences
           connection.create_table :cats, id: :uuid, default: "uuid_generate_v4()"
           assert_nothing_raised { rename_table :cats, :felines }
           assert connection.table_exists? :felines
+          refute connection.table_exists? :cats
         ensure
           connection.drop_table :cats, if_exists: true
           connection.drop_table :felines, if_exists: true