Could someone explain this (transaction-related)?

rubyonrails-talk
1

Hi all,

I was testing, and found a nested transaction (which I know is bad), and there's something I don't understand. If an exception occurs during a transaction, it is supposed to roll back. In a nested transaction, where an exception is raised out of the 'inner' transaction, this doesn't occur. However, if I catch the exception and manually call 'connection.rollback_db_transaction', it works, e.g.:

Applicant.transaction do   a = Applicant.find(1)   begin     Applicant.transaction do       a.first_name = 'bar'       a.save!       raise "Foo" # This does not roll back the transaction...     end   rescue     Applicant.connection.rollback_db_transaction # But this will   end end

I don't see why it makes a difference if I call rollback_db_transaction in rescue. I thought that happened automatically. Looking at the source, I can't see where it happens.

Thanks if anyone can clear this up for me. I am trying to use transactional fixtures for all my tests, and this is a sticking point. If I can understand this, I think I can convert them all.

2

Hi all,

I was testing, and found a nested transaction (which I know is bad),
and there's something I don't understand. If an exception occurs during a transaction, it is supposed to roll back. In a nested transaction, where an exception is raised out of the 'inner' transaction, this doesn't occur. However, if I catch the exception and manually call 'connection.rollback_db_transaction', it works, e.g.:

Rails doesn't support nested transactions, so only the outer one is
actually doing anything, by rescuing the exception you are preventing
rails from doing the rollback.

Fred