Using Papertrail's attribute_name_was - ruby-on-rails

Question

I have a request that makes several changes to the same record, however I only need to store a version when one of the attributes changes from false to true. I tried the following:
has_paper_trail on: [:update],
only: {
redone: Proc.new { |srv|
srv.redone == true && srv.redone_was == false
},
}
But I am still getting versions on changes that do not involve the redone attribute changing from false to true... This is an excerpt from the log:
(0.7ms) BEGIN
SQL (11.3ms) UPDATE "servicings" SET "redone" = $1, "redo_reason" = $2, "updated_at" = $3 WHERE "servicings"."id" = $4 [["redone", false], ["redo_reason", nil], ["updated_at", 2018-07-19 22:46:15 UTC], ["id", 218762]]
SQL (9.7ms) INSERT INTO "versions" ("item_type", "item_id", "event", "object", "object_changes", "created_at") VALUES ($1, $2, $3, $4, $5, $6) RETURNING "id" [["item_type", "Servicing"], ["item_id", 218762], ["event", "update"], ["object", "---\nid: 218762\nwork_order_id: 7462\narea_id: 16563\nhigh_priority: false\ncompleted_at: \ncreated_at: 2018-07-10 19:45:36.245612000 Z\nupdated_at: 2018-07-19 22:14:11.143007000 Z\nassignee_id: 90\nclaimed_by_id: \ncompleted_by_id: 90\noccupied_at: \ndeleted_at: \nstatus: open\napproval_status: \nredone: true\nunable_reason: \nredo_reason: testing paper_trail\napproving_user_id: \napproving_user_name: \napproved_at: \n"], ["object_changes", "---\nredone:\n- true\n- false\nredo_reason:\n- testing paper_trail\n- \nupdated_at:\n- 2018-07-19 22:14:11.143007000 Z\n- 2018-07-19 22:46:15.680447100 Z\n"], ["created_at", 2018-07-19 22:46:15 UTC]]
(5.6ms) COMMIT
(2.0ms) BEGIN
(0.8ms) COMMIT
(1.5ms) BEGIN
SQL (9.1ms) UPDATE "servicings" SET "updated_at" = $1, "status" = $2 WHERE "servicings"."id" = $3 [["updated_at", 2018-07-19 22:46:15 UTC], ["status", "completed"], ["id", 218762]]
SQL (2.8ms) INSERT INTO "versions" ("item_type", "item_id", "event", "object", "object_changes", "created_at") VALUES ($1, $2, $3, $4, $5, $6) RETURNING "id" [["item_type", "Servicing"], ["item_id", 218762], ["event", "update"], ["object", "---\nid: 218762\nredone: false\nredo_reason: \nwork_order_id: 7462\narea_id: 16563\nhigh_priority: false\ncompleted_at: \ncreated_at: 2018-07-10 19:45:36.245612000 Z\nupdated_at: 2018-07-19 22:46:15.680447100 Z\nassignee_id: 90\nclaimed_by_id: \ncompleted_by_id: 90\noccupied_at: \ndeleted_at: \nstatus: open\napproval_status: \nunable_reason: \napproving_user_id: \napproving_user_name: \napproved_at: \n"], ["object_changes", "---\nupdated_at:\n- 2018-07-19 22:46:15.680447100 Z\n- 2018-07-19 22:46:15.981721300 Z\nstatus:\n- open\n- completed\n"], ["created_at", 2018-07-19 22:46:15 UTC]]
(8.7ms) COMMIT
WorkOrder Load (15.1ms) SELECT "work_orders".* FROM "work_orders" WHERE "work_orders"."deleted_at" IS NULL AND "work_orders"."id" = $1 LIMIT $2 [["id", 7462], ["LIMIT", 1]]
(1.2ms) BEGIN
SQL (16.3ms) UPDATE "servicings" SET "completed_at" = $1, "updated_at" = $2 WHERE "servicings"."id" = $3 [["completed_at", 2018-07-19 22:46:16 UTC], ["updated_at", 2018-07-19 22:46:16 UTC], ["id", 218762]]
SQL (7.5ms) INSERT INTO "versions" ("item_type", "item_id", "event", "object", "object_changes", "created_at") VALUES ($1, $2, $3, $4, $5, $6) RETURNING "id" [["item_type", "Servicing"], ["item_id", 218762], ["event", "update"], ["object", "---\nid: 218762\nredone: false\nredo_reason: \nwork_order_id: 7462\narea_id: 16563\nhigh_priority: false\ncompleted_at: \ncreated_at: 2018-07-10 19:45:36.245612000 Z\nupdated_at: 2018-07-19 22:46:15.981721300 Z\nassignee_id: 90\nclaimed_by_id: \ncompleted_by_id: 90\noccupied_at: \ndeleted_at: \nstatus: completed\napproval_status: \nunable_reason: \napproving_user_id: \napproving_user_name: \napproved_at: \n"], ["object_changes", "---\ncompleted_at:\n- \n- 2018-07-19 22:46:16.111954100 Z\nupdated_at:\n- 2018-07-19 22:46:15.981721300 Z\n- 2018-07-19 22:46:16.150183500 Z\n"], ["created_at", 2018-07-19 22:46:16 UTC]]
(2.7ms) COMMIT
What could I be doing wrong?

Answer 1

It's probably because PaperTrail's callback executes after the update. If that's the case, redone_was will always be equal to the current redone value.
You should store your redone_was value somewhere before updating.
class Klass
attr_accessor :old_redone_value
before_save :store_old_redone_value
has_paper_trail on: [:update],
only: {
redone: Proc.new { |srv|
srv.redone == true && srv.old_redone_value == false
},
}
def store_old_redone_value
self.old_redone_value = redone_was
end
end
That's the idea. It's not the best solution, and might not work -- but, it'll lead you somewhere.