Ecto Fragment Macro help

Hi, I’m trying to create an ecto fragment to update a set of records but I’m running into some issues, would be very thankful if someone can explain me what I’m doing wrong here.

I have a schema for a user resource:

defmodule User.Scroll do
  use Ecto.Schema

  schema("user_scrolls") do
    belongs_to :user, User

    field :scroll_id,          :integer
    field :from_type,          User.Scroll.FromType
    field :from_id,            :id
    field :only_owner,         :boolean, default: false

    field :locked,             :boolean, default: false
    field :locked_by,          {:array, :string}, default: []

    field :locked_duel,        :id
    field :locked_chaos_brawl, :id
    field :locked_tournament,  :id
    field :locked_open,        :binary_id
    field :locked_until,       :utc_datetime_usec
    field :borrowed,           :boolean, default: false
    field :borrowed_from,      :id

    timestamps(type: :utc_datetime_usec)
  end
end

This record is updated at some point and ends up getting in the following state:

iex(59244833@o.local)1> [s] = User.Scroll |> where([s], s.locked) |> Db.Repo.all
[debug] QUERY OK source="user_scrolls" db=1.1ms queue=0.7ms idle=1752.8ms
SELECT u0."id", u0."user_id", u0."scroll_id", u0."from_type", u0."from_id", u0."only_owner", u0."locked", u0."locked_by", u0."locked_duel", u0."locked_chaos_brawl", u0."locked_tournament", u0."locked_open", u0."locked_until", u0."borrowed", u0."borrowed_from", u0."inserted_at", u0."updated_at" FROM "user_scrolls" AS u0 WHERE (u0."locked") []
[
  %User.Scroll{
    __meta__: #Ecto.Schema.Metadata<:loaded, "user_scrolls">,
    borrowed: false,
    borrowed_from: nil,
    from_id: 1,
    from_type: :regular,
    id: 2,
    inserted_at: ~U[2020-08-17 10:23:27.469625Z],
    locked: true,
    locked_by: ["open-duel-5ade3b99-5e50-4069-bb08-ddf4a8bf9d97::1"],
    locked_chaos_brawl: nil,
    locked_duel: nil,
    locked_open: "5ade3b99-5e50-4069-bb08-ddf4a8bf9d97",
    locked_tournament: nil,
    locked_until: nil,
    only_owner: true,
    scroll_id: 28,
    updated_at: ~U[2020-08-17 10:23:27.469625Z],
    user: #Ecto.Association.NotLoaded<association :user is not loaded>,
    user_id: 1
  }
]

The relevant pieces here are the locked_by and locked_open fields.
The string in the locked_by array field is generated through:

defmodule Shared.Locks do
  def generate_locked_by(:open_duel, od_id, user_id) do
    "open-duel-#{od_id}::#{user_id}"
  end
end

I then have a function that runs an update query using a macro:

def unblock_players_resources(players_ids, %Open{id: od_id, type: :PLAYGROUND}) do
    User.Scroll
    |> where([s], s.user_id in ^players_ids and s.locked and s.locked_open == ^od_id)
    |> update([s], set: [locked_by: remove_from_blocked_by(field(s, :locked_by), :open_duel, players_ids, od_id), locked_open: nil])
    |> Db.Repo.update_all([])
end

And the remove_from_blocked_by macro is defined as:

defmodule Macros.Resources do
  defmacro remove_from_blocked_by(field, type, player_1, od_id) do
    quote do
      fragment("array_remove(?, ?)", unquote(field), ^Shared.Locks.generate_locked_by(unquote(type), unquote(od_id), unquote(player_1)))
    end
  end
end

This generates the following query:

[debug] QUERY OK source="user_scrolls" db=1.1ms queue=0.9ms idle=1898.3ms
UPDATE "user_scrolls" AS u0 SET "locked_by" = array_remove(u0."locked_by", $1), "locked_open" = NULL WHERE ((u0."user_id" = ANY($2) AND u0."locked") AND (u0."locked_open" = $3)) [<<111, 112, 101, 110, 45, 100, 117, 101, 108, 45, 53, 97, 100, 101, 51, 98, 57, 57, 45, 53, 101, 53, 48, 45, 52, 48, 54, 57, 45, 98, 98, 48, 56, 45, 100, 100, 102, 52, 97, 56, 98, 102, 57, 100, 57, 55, 58, 58, 1>>, [1], <<90, 222, 59, 153, 94, 80, 64, 105, 187, 8, 221, 244, 168, 191, 157, 151>>]

So it seems the first argument ($1) is being passed as binary where I would expect it to be a string. I’ve tried to use also type(^Shared.Locks.generate_locked_by....., :string) but it ends up in the same form.

If from psql I execute this query it correctly removes the element from the array:

awars_dev=# SELECT * from user_scrolls AS s WHERE s.locked;
 id | user_id | scroll_id | from_type | from_id | locked |                      locked_by                      | locked_duel | locked_chaos_brawl | locked_tournament | locked_open | locked_until | borrowed | borrowed_from | only_owner |        inserted_at         |         updated_at         
----+---------+-----------+-----------+---------+--------+-----------------------------------------------------+-------------+--------------------+-------------------+-------------+--------------+----------+---------------+------------+----------------------------+----------------------------
  2 |       1 |        28 | regular   |       1 | t      | {open-duel-5ade3b99-5e50-4069-bb08-ddf4a8bf9d97::1} |             |                    |                   |             |              | f        |               | t          | 2020-08-17 10:23:27.469625 | 2020-08-17 10:23:27.469625
(1 row)

awars_dev=# UPDATE user_scrolls AS s SET locked_by = array_remove(locked_by, 'open-duel-5ade3b99-5e50-4069-bb08-ddf4a8bf9d97::1') WHERE s.locked;
UPDATE 1

The %Open{} struct id is a binary id, it’s correctly cast in the unblock_players_resources() query, as it finds a record and updates correctly the locked_open field, but somehow I can’t get the macro fragment for the array_remove to be a varchar/string of the form "open-duel-f184133f-a996-4883-a129-8b307c6a6634::1" instead it’s always being set as a binary.
I’ve also tried in the fragment to use type(^Shared.Locks.generate_locked_by(unquote(type), unquote(od_id), unquote(player_1)), :string) to no avail, the result is the same query.

Does anyone have any idea on how I can get this working or what I’m doing wrong? Thanks