apply_valid_rows only matched {:ok, _} and {:error, %Changeset{}}, so when
Radio.create_contact returned {:error, :duplicate, existing} — the race
window where preview flagged a row as new but another writer inserts the
same contact before the worker picks up the chunk — the reduce callback
crashed with FunctionClauseError. Oban retried the chunk, rolling back
the Postgrex transaction and surfacing the DBConnection errors the
operator was seeing.
Treat :duplicate as a silent skip: the row is already in the DB, there
is nothing to insert, and the counter should not double-count the existing
contact as an error either.
Graham McIntire
3cb367c898