Unable to handle foreign key constraint errors on deleting

[cbishopvelti]

Elixir version

1.18.1

Database and Version

{:exqlite, "0.29.0"} {:ecto_sqlite3, "0.18.1"}

Ecto Versions

3.12.1

Database Adapter and Versions (postgrex, myxql, etc)

{:exqlite, "0.29.0"} {:ecto_sqlite3, "0.18.1"}

Current behavior

Create a two tables,
create table(:venue) do
end
create table(:event) do
add :venue_id, references(
:venue
on_delete: :restrict
)
end
Try and delete a venue:
Venue |> Ecto.Changeset.change() |> Ecto.Changeset.no_assoc_constraint(:event) |> Repo.delete()
I get a runtime error:

#PID<0.750.0> running Phoenix.Endpoint.SyncCodeReloadPlug (connection #PID<0.749.0>, stream id 1) terminated
Server: 127.0.0.1:4000 (http)
Request: POST /api/graphql
** (exit) an exception was raised:
    ** (Ecto.ConstraintError) constraint error when attempting to delete struct:

    * nil (foreign_key_constraint)

If you would like to stop this constraint violation from raising an
exception and instead add it as an error to your changeset, please
call `foreign_key_constraint/3` on your changeset with the constraint
`:name` as an option.

The changeset defined the following constraints:

    * "event_venue_id_fkey" (foreign_key_constraint)

Expected behavior

The error should go into the changeset.

There doesn't appear to be a way to match against "* nil (foreign_key_constraint)" as if I add the opt name: nil, it will use the default generated fk name.

[v0idpwn]

Hi, @cbishopvelti, thanks for reporting.

This is due to a limitation in exqlite/ecto_sqlite3. It's tracked here: elixir-sqlite/ecto_sqlite3#124 and someone commented a workaround that maybe works for you.

[josevalim]

Thank you @v0idpwn, please refer to the ecto_sqlite3 issue then. If there is something that needs to be done on Ecto @warmwaffles, please let us know!

[warmwaffles]

I believe this is mostly all in sqlite's realm. I'll need to play with the error returns and figure out if there is a way to make this play nicely with the other adapters. I don't have the link, but on sqlite's forum there were a few places the FK error formatting should be changed but upstream won't because it's been formatted the way it has for years.