Operator-asked 2026-06-01 after the Dymkens orphan investigation
(Scribe plan #540). The pre-2030 sidecar-synthetic Source pattern
(`sidecar:<platform>:<slug>` enabled=false rows) existed solely to
satisfy `Post.source_id NOT NULL`, and leaked into the Subscriptions
UI as phantom subscriptions. Now the data model says what's true:
filesystem-imported content with no live subscription has NULL
source_id, full stop.
## Schema (alembic 0030)
- `post.artist_id` — NEW NOT NULL FK to artist (CASCADE). Backfilled
from source.artist_id in the migration. Indexed for the artist-filter
queries.
- `post.source_id` — NOT NULL → nullable; FK ondelete CASCADE → SET
NULL. Deleting a Source detaches its Posts instead of destroying
archived content (subscription ends, archive stays).
- `image_provenance.source_id` — same nullable + SET NULL.
- Partial unique index `uq_post_artist_external_id_null_source` on
(artist_id, external_post_id) WHERE source_id IS NULL — guards
filesystem-import dedup since the existing source-bound unique
ignores NULLs (Postgres treats NULL != NULL).
- Sidecar synthetic Sources deleted: NULL out FKs in post,
image_provenance first, then DELETE FROM source WHERE url LIKE
'sidecar:%'. The Dymkens cleanup.
## Model + service changes
- `Post.source_id` → `Mapped[int | None]`; new `Post.artist_id`
denormalized.
- `ImageProvenance.source_id` → `Mapped[int | None]`.
- Importer: `_source_for_sidecar` (synthetic-creating) →
`_lookup_source_for_sidecar` (returns None when no subscription).
`_find_or_create_post` takes required `artist_id`; matches on
(source_id, external_post_id) for source-bound posts or
(artist_id, external_post_id) for NULL-source posts.
- Service queries switched off the Source detour to use Post.artist_id
directly: post_feed_service.scroll/around/get_post (LEFT JOIN to
Source so NULL-source posts surface); artist_service date_row/
activity/post_count; provenance_service.for_image/for_post (LEFT
JOIN); gallery_service._provenance_exists_where_artist via
Post.artist_id instead of ImageProvenance.source_id → Source.
- `_to_dict` and provenance dict-builders emit `"source": null` for
NULL-source rows.
## Frontend
- `ProvenancePanel.vue` + `PostCard.vue`: render `e.source?.platform
?? 'filesystem import'` so NULL-source posts get a clear
"filesystem import" affordance instead of a NaN crash.
## Tests
- `test_importer_upsert_helpers`: removed the four synthetic-anchor
tests; added `_find_or_create_post_idempotent_with_null_source`
(dedup via the partial unique index) and
`_lookup_source_for_sidecar_returns_*` (existing-subscription +
none cases). The existing `_find_or_create_post_idempotent` now
also passes `artist_id` and asserts it.
- 8 other test files updated: every direct `Post(...)` construction
gains `artist_id=<artist>.id`. The `_seed_post` helper in
`test_post_feed_service` looks up artist_id from the source row so
callsites stay one-arg.
## Verification on deploy
After alembic 0030 runs:
- `SELECT COUNT(*) FROM source WHERE url LIKE 'sidecar:%'` → 0.
- `SELECT COUNT(*) FROM post WHERE source_id IS NULL` → count of
filesystem-imported posts (Dymkens + any other historical).
- Every `post.artist_id` non-null; consistent with source.artist_id
for source-bound rows.
- Subscriptions tab: no Dymkens phantom row.
- Artist detail → Posts/Gallery: Dymkens's content still reachable
via Post.artist_id.
- Provenance panel renders "filesystem import" chip for NULL-source
posts; PostCard same.
## Out of scope
- UI to manage/delete orphan NULL-source Posts. Data model is right;
UI follows if operator wants it.
bvandeusen
2f66de2928