Fix sequence name with abstract classes.

[ebeigarts]

With oracle-enhanced this test started to fail (I think it was after this commit):

  1) Error:
test_validate_straight_inheritance_uniqueness(UniquenessValidationTest):
OCIError: ORA-02289: sequence does not exist
    /Users/beigaedg/.rvm/gems/ruby-1.9.2-p290@rails/gems/ruby-oci8-2.0.6/lib/oci8/oci8.rb:288:in `exec'
    /Users/beigaedg/.rvm/gems/ruby-1.9.2-p290@rails/gems/ruby-oci8-2.0.6/lib/oci8/oci8.rb:116:in `exec'
    /Users/beigaedg/code/oracle-enhanced/lib/active_record/connection_adapters/oracle_enhanced_oci_connection.rb:469:in `exec'
    /Users/beigaedg/code/oracle-enhanced/lib/active_record/connection_adapters/oracle_enhanced_oci_connection.rb:172:in `select'
    /Users/beigaedg/code/oracle-enhanced/lib/active_record/connection_adapters/oracle_enhanced_connection.rb:83:in `select_one'
    /Users/beigaedg/code/oracle-enhanced/lib/active_record/connection_adapters/oracle_enhanced_connection.rb:89:in `select_value'
    /Users/beigaedg/code/oracle-enhanced/lib/active_record/connection_adapters/oracle_enhanced_adapter.rb:761:in `next_sequence_value'
    /Users/beigaedg/code/rails/activerecord/lib/active_record/relation.rb:47:in `insert'
    /Users/beigaedg/code/rails/activerecord/lib/active_record/persistence.rb:316:in `create'
    /Users/beigaedg/code/rails/activerecord/lib/active_record/timestamp.rb:57:in `create'
    /Users/beigaedg/code/rails/activerecord/lib/active_record/callbacks.rb:268:in `block in create'
    /Users/beigaedg/code/rails/activesupport/lib/active_support/callbacks.rb:393:in `_run_create_callbacks'
    /Users/beigaedg/code/rails/activesupport/lib/active_support/callbacks.rb:81:in `run_callbacks'
    /Users/beigaedg/code/rails/activerecord/lib/active_record/callbacks.rb:268:in `create'
    /Users/beigaedg/code/rails/activerecord/lib/active_record/persistence.rb:297:in `create_or_update'
    /Users/beigaedg/code/rails/activerecord/lib/active_record/callbacks.rb:264:in `block in create_or_update'
    /Users/beigaedg/code/rails/activesupport/lib/active_support/callbacks.rb:393:in `_run_save_callbacks'
    /Users/beigaedg/code/rails/activesupport/lib/active_support/callbacks.rb:81:in `run_callbacks'
    /Users/beigaedg/code/rails/activerecord/lib/active_record/callbacks.rb:264:in `create_or_update'
    /Users/beigaedg/code/rails/activerecord/lib/active_record/persistence.rb:37:in `save'
    /Users/beigaedg/code/rails/activerecord/lib/active_record/validations.rb:50:in `save'
    /Users/beigaedg/code/rails/activerecord/lib/active_record/attribute_methods/dirty.rb:22:in `save'
    /Users/beigaedg/code/rails/activerecord/lib/active_record/transactions.rb:241:in `block (2 levels) in save'
    /Users/beigaedg/code/rails/activerecord/lib/active_record/transactions.rb:295:in `block in with_transaction_returning_status'
    /Users/beigaedg/code/rails/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb:190:in `transaction'
    /Users/beigaedg/code/rails/activerecord/lib/active_record/transactions.rb:208:in `transaction'
    /Users/beigaedg/code/rails/activerecord/lib/active_record/transactions.rb:293:in `with_transaction_returning_status'
    /Users/beigaedg/code/rails/activerecord/lib/active_record/transactions.rb:241:in `block in save'
    /Users/beigaedg/code/rails/activerecord/lib/active_record/transactions.rb:252:in `rollback_active_record_state!'
    /Users/beigaedg/code/rails/activerecord/lib/active_record/transactions.rb:240:in `save'
    /Users/beigaedg/code/rails/activerecord/lib/active_record/base.rb:533:in `create'
    /Users/beigaedg/code/rails/activerecord/test/cases/validations/uniqueness_validation_test.rb:269:in `test_validate_straight_inheritance_uniqueness'
    /Users/beigaedg/.rvm/gems/ruby-1.9.2-p290@rails/gems/mocha-0.9.12/lib/mocha/integration/mini_test/version_142_to_172.rb:27:in `run'
    /Users/beigaedg/code/rails/activesupport/lib/active_support/testing/setup_and_teardown.rb:35:in `block in run'
    /Users/beigaedg/code/rails/activesupport/lib/active_support/callbacks.rb:415:in `_run_setup_callbacks'
    /Users/beigaedg/code/rails/activesupport/lib/active_support/callbacks.rb:81:in `run_callbacks'
    /Users/beigaedg/code/rails/activesupport/lib/active_support/testing/setup_and_teardown.rb:34:in `run'

I also added a new test case which failed also on PostgreSQL.

PostgreSQL:

  1) Error:
test_sequence_name_with_abstract_class(BasicsTest):
NoMethodError: undefined method `split' for nil:NilClass
    /Users/beigaedg/code/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb:897:in `default_sequence_name'
    /Users/beigaedg/code/rails/activerecord/lib/active_record/base.rb:736:in `reset_sequence_name'
    /Users/beigaedg/code/rails/activerecord/lib/active_record/base.rb:725:in `sequence_name'
    /Users/beigaedg/code/rails/activerecord/lib/active_record/base.rb:727:in `sequence_name'
    ./test/cases/base_test.rb:1609:in `test_sequence_name_with_abstract_class'
    /Users/beigaedg/.rvm/gems/ruby-1.9.2-p290@rails/gems/mocha-0.9.12/lib/mocha/integration/mini_test/version_142_to_172.rb:27:in `run'
    /Users/beigaedg/code/rails/activesupport/lib/active_support/testing/setup_and_teardown.rb:35:in `block in run'
    /Users/beigaedg/code/rails/activesupport/lib/active_support/callbacks.rb:415:in `_run_setup_callbacks'
    /Users/beigaedg/code/rails/activesupport/lib/active_support/callbacks.rb:81:in `run_callbacks'
    /Users/beigaedg/code/rails/activesupport/lib/active_support/testing/setup_and_teardown.rb:34:in `run'

Oracle:

  1) Failure:
test_sequence_name_with_abstract_class(BasicsTest) [./test/cases/base_test.rb:1611]:
<"projects_seq"> expected but was
<"_seq">.

[jonleighton]

Thanks for reporting the bug. I think perhaps we should be using base_class here. E.g. something like:

def sequence_name
  if base_class == self
    @seqence_name ||= reset_sequence_name
  else
    (@sequence_name ||= nil) || base_class.sequence_name
  end
end

Could you look into that please?

[ebeigarts]

Yes, it works, I also updated my pull request.

[agarbutt]

This seems to break code where an inheritance tree defines both a table_name_prefix and defines a sequence pattern for all models inheriting from this tree.

Given:

class A < B
end

class B < ActiveRecord::Base
  self.abstract_class = true
  self.table_name_prefix = 'core.'
  self.sequence_name = :autogenerated
end

The queries will work correctly, but because of the behavior of base_class, when the connection asks for the sequence_name, base_class returns A and not B. A then resets the sequence_name and it is no longer pulled from the super, instead, you get a sequence name 'core.a_seq'

Seems we are missing a test case where the sequence_name is set in the base class and is retained in the subclass.

Are there any suggestions for work arounds?