Loss of significant error messages

[stavro]

Wrapping all calls to insert, update, etc causes valuable information to be lost about normal database transactions.

With a schema that uses Changeset.foreign_key_constraint/3 or Changeset.no_assoc_constraint, the messages are lost.

def prepare_delete(category) do
  category
  |> change
  |> no_assoc_constraint(:topics)
end



# Without using ExAudit.Repo

Category
|> Repo.get(id)
|> Category.prepare_delete
|> Repo.delete

# {:error,
#  #Ecto.Changeset<action: :delete, changes: %{},
#   errors: [topics: {"are still associated with this entry", []}],
#   data: #Category<>, valid?: false>}


# Using ExAudit.Repo

Category
|> Repo.get(id)
|> Category.prepare_delete
|> Repo.delete

# {:error, :rollback}

I realize this is not a straightforward (or even possible) thing to fix, but it should be very well documented that database errors and constraint messages are lost. I have a few places where there are multiple database-enforced constraints, and when using the provided Repo module, I have no way of knowing which constraint failed

[narrowtux]

Seems like Repo.transaction will return {:error, :rollback} all the time, I thought returning the original return value of the wrapped repo function would suffice. I'm looking into alternatives, since I really want everything to work like before.

[narrowtux]

In the hopes that Ecto.Multi will not lose the error messages, I rewrote my transaction code to use a multi. Now I've just got to write a test

[narrowtux]

Fixed in 0.3.1 @stavro