[Bug]: uc_tag_sync ignores standalone uc_table / uc_column semantic links (only reads data_contract_schema + asset)

[mvkonchits-db]

Summary

uc_tag_sync propagates a concept's IRI to a UC governed tag ONLY when the concept is linked via a data_contract_schema or an asset entity. A concept linked directly to a physical object with entity_type = 'uc_table' (or uc_column, uc_schema, uc_catalog) is silently skipped — no tag is written, no error.

Evidence (verified on FEVM valcon-demo)

src/backend/src/workflows/uc_tag_sync/uc_tag_sync.py has two readers:

• read_contracts_and_links — joins entity_semantic_links with WHERE el.entity_type = 'data_contract_schema' (approx L216).
• read_assets_and_links — joins entity_semantic_links with WHERE esl.entity_type = 'asset' (approx L383) and WHERE at.name IN ('Table','View').

Neither reads links whose entity_type is uc_table / uc_column / uc_schema / uc_catalog.

Repro:

1. Link a concept directly to a UC table: POST /api/semantic-links/ {entity_id: "main.finance.fact_expenses", entity_type: "uc_table", iri: "urn:glossary:finance/opex-spend"}.
2. GET /api/knowledge/tag-delivery-stats reports it as eligible (eligible: 1) — the app's read model counts uc_table links.
3. Run uc_tag_sync → log shows Found 0 datasets from contracts / Found 0 datasets from assets / Processing 0 datasets / Summary: updated=0. The eligible link is never tagged.

By contrast, the SAME concept linked via an asset row (asset_type Table, location = demo_catalog.e2e_import.fct_revenue) tags correctly: the job writes ontos_semantic_opex_spend = urn:glossary:finance/opex-spend on the table (verified via information_schema.table_tags).

Impact

• The Enrich tag-delivery read model and the sync job disagree: the UI shows a uc_table-linked concept as eligible/pending forever, but the job never delivers it. Confusing and looks like a broken sync.
• Users who link concepts straight to physical UC objects (a natural, common action) get no tags.

Suggested fix

Add a reader path for direct physical links (entity_type IN ('uc_table','uc_column','uc_schema','uc_catalog')) where entity_id is (or resolves to) the UC FQN, and feed those into the same DatasetTagInfo aggregation the asset/contract paths use. The tag key/value formats already exist (semantic_assignment config). Alternatively, make tag-delivery-stats count only the entity types the job can actually deliver, so the read model and the job agree — but delivering uc_table links is the better fix.

Notes

• Not a regression from the concept-versioning work — the versioning changes never touched this job; this gap predates them. Surfaced while validating that versioning did not break UC tag propagation (it did not — the asset-linked path tags end to end cleanly).