Migration generated when adding a reference can't be rolled back about ash_postgres

[zachdaniel]

Very strange. I'll have to look into both of these when I get a chance.

[zachdaniel]

I believe I've just found and fixed the other issue as well :)

[sevenseacat]

Interestingly, I actually needed a migration to fix two references and they were generated differently -

  def down do
    # This one will work
    drop constraint(:instance_logs, "instance_logs_instance_id_fkey")

    alter table(:instance_logs) do
      modify :instance_id,
             references(:instances,
               column: :id,
               prefix: "public",
               name: "instance_logs_instance_id_fkey",
               type: :uuid
             )

      # I don't even know where this came from, the column has not changed
      modify :associated_email, :text
    end

    # This one won't work
    alter table(:experiments) do
      modify :organisation_id,
             references(:organisations,
               column: :id,
               prefix: "public",
               name: "experiments_organisation_id_fkey",
               type: :uuid
             )
    end

    drop constraint(:experiments, "experiments_organisation_id_fkey")
  end

[zachdaniel]

Interesting...so I think what might be happening is a non deterministic sorting. I was having trouble with the original sorting algorithm so I switched it to use digraph, and without the proper dependency, it could sometimes come out in the right order and sometimes in the wrong. Thanks for the report :) will take a look

[zachdaniel]

      # I don't even know where this came from, the column has not changed
      modify :associated_email, :text

This is concerning.

[sevenseacat]

That one might be a separate issue - I have a field associated_email which is text, and I added an association that also uses it as a possible lookup field. (The email might match a valid user, but might not.)

    belongs_to :user, MyApp.Accounts.User do
      api MyApp.Accounts
      source_attribute :associated_email
      destination_attribute :email
    end

Adding the association is what caused the migration to add modify :associated_email, :text to both up and down.

[zachdaniel]

Could it be because the default field type for belongs_to is :uuid? Is the up migration changing the field type to :uuid? You might want attribute_type :string.

[sevenseacat]

Maybe. No, both, are setting it to text -

  def up do
    alter table(:instance_logs) do
      modify :associated_email, :text
    end
  end

  def down do
    alter table(:instance_logs) do
      modify :associated_email, :text
    end
  end

[zachdaniel]

Pushing a fix for the unrollback-able migration. Still not sure on the unnecessary attribute migration, but we'll just have to leave that for another issue :)