add_reference_concurrently with polymorphic option

[brigidspeed23]

Gem version: 0.19.4 Ruby version: 3.3.4 Rails version: 8.0.0.alpha

Hi !!

We're seeing some undesirable behaviour while running an add_reference_concurrently migration with the polymorphic flag enabled eg

class Btest1Migration < ActiveRecord::Migration[8.0]
  regions :all

  disable_ddl_transaction!

  def up
    add_reference_concurrently :automatic_break_templates, :pay_condition_settable, polymorphic: true
  end
end

When we run the migration the first time, it fails with error ERROR: column "pay_condition_settable_type" does not exist.

We can see from the raw SQL, that the migration only creates the _id column and isn't attempting to create the _type column:

This is the first issue: creation column _type is not attempted before creation of index.

Checking the table schema at this point and both the _id and _type columns and the index have not been added (as expected for the migration failing).

Running the migration a second time, and it also fails with error ERROR: column "pay_condition_settable_type" does not exist, however this time we can see from the raw SQL that the there is no attempt to create either the _id or _type column (although neither of these exist) prior to attempting to create the index:

This is the second issue: inconsistent behaviour of the migration between subsequent runs.

The first issue might be a fairly simple bug fix, but we'd be interested if anyone has any thoughts or insight on the second issue as well.

Many thanks in advance !!

[fatkodima]

Thanks for reporting! Yeah, so this is a bug. And the whole operation should be idempotent, so subsequent runs should be no-ops.

I will fix it and release a new version tomorrow.

[fatkodima]

Can you please confirm that the changes from master actually fixes your problem? And so I will release a new version.