# `PhoenixKit.Migrations.Postgres.V70`
[🔗](https://github.com/BeamLabEU/phoenix_kit/blob/v1.7.165/lib/phoenix_kit/migrations/postgres/v70.ex#L1)

V70: Re-backfill UUID FK columns silently skipped in V56/V63.

## Background

V56 introduced UUID FK companion columns (via UUIDFKColumns) with a backfill
that populated each FK column from the corresponding source table's `uuid`
column.  Two bugs in V56/V63 could cause the backfill to be skipped silently:

1. **Type mismatch** — On databases where `phoenix_kit_email_logs.uuid` was
   created as `character varying` instead of the native PostgreSQL `uuid` type
   (because a manual migration pre-empted V40's proper ADD COLUMN), the
   backfill UPDATE fails with `ERROR 42804 datatype_mismatch`.

2. **Broken rescue** — V56's `backfill_uuid_fk` had a `rescue _ -> :ok` clause
   intended to swallow the error.  However, a failed PostgreSQL statement puts
   the connection's transaction in an aborted state (ERROR 25P02), so all
   subsequent execute/1 calls fail even though Elixir caught the exception.
   The first error (type mismatch) is reported; the migration rolls back; the
   DB stays at v55.  Alternatively, if the migration somehow succeeded, the
   backfill was still skipped and `email_log_uuid` rows were filled with
   random UUIDs by `UUIDFKColumns.add_constraints/1`'s NULL-fill fallback.

V63 had the same issue for `matched_email_log_uuid` without even a rescue.

## What This Migration Does

1. Converts `phoenix_kit_email_logs.uuid` to native `uuid` type if still
   `character varying` (root-cause fix).

2. Re-backfills `email_log_uuid` in `phoenix_kit_email_events`:
   - Rows whose `email_log_uuid` does NOT reference a real email log uuid
     (random UUID written by the NULL-fill fallback) are reset to NULL first.
   - Then the proper JOIN-based backfill is re-run.

3. Re-backfills `matched_email_log_uuid` in `phoenix_kit_email_orphaned_events`
   (same pattern as above).

All operations are idempotent — safe on every install, including fresh ones
where the columns were backfilled correctly from the start.

# `down`

# `up`

---

*Consult [api-reference.md](api-reference.md) for complete listing*