fix(3-M.b): apply_enrichment always attaches _enriched for declared adapters

Coordless events such as removal tombstones with null lat/lon, from adapters that declare enrichment_locations, previously fell off the loop without writing _enriched and carried no geocoder bundle at all, violating the every-event-carries-_enriched design rule. Add a post-loop fallback that resolves the null location to an all-null bundle per enricher. Adapters with no enrichment_locations remain skipped.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/central/supervisor.py

@@ -76,9 +76,12 @@ async def apply_enrichment(
 
     No-op when the adapter declares no enrichment_locations or no enrichers
     are registered. Uses the first (lat_path, lon_path) tuple that resolves to
-    a non-null coordinate pair in event.data. Each enricher's result is keyed
-    by enricher.name. Mutates the data dict in place (Event is frozen, but its
-    data dict is not — this avoids a model_copy on every published event).
+    a non-null coordinate pair in event.data. If no declared pair resolves to
+    coordinates, still attaches an all-null bundle so that every event from an
+    enriched adapter carries _enriched (consumers get a stable field set).
+    Each enricher's result is keyed by enricher.name. Mutates the data dict in
+    place (Event is frozen, but its data dict is not — this avoids a
+    model_copy on every published event).
     """
     if not enrichment_locations or not enrichers:
         return
@@ -93,6 +96,15 @@ async def apply_enrichment(
             enriched[enricher.name] = await enricher.enrich(location)
         event.data["_enriched"] = enriched
         return
+    # No declared pair resolved to coordinates. Still attach _enriched: each
+    # enricher resolves the null location to its own all-null bundle (per the
+    # never-raise contract), so coordless events (e.g. removal tombstones)
+    # carry the same shape as enriched ones.
+    null_location = {"lat": None, "lon": None}
+    enriched = {}
+    for enricher in enrichers:
+        enriched[enricher.name] = await enricher.enrich(null_location)
+    event.data["_enriched"] = enriched
 
 # Stream subject mappings -- derived from the registry; every stream is included
 # (META too: supervisor must create it in JetStream even though archive skips it).

tests/test_apply_enrichment_coordless.py

@@ -0,0 +1,78 @@
+"""Regression tests for apply_enrichment's coordless path.
+
+Design principle: every event from an adapter that declares enrichment_locations
+must carry data["_enriched"] — populated when coordinates resolve, an all-null
+bundle when they don't (e.g. removal tombstones with no lat/lon). Adapters that
+declare no enrichment_locations are still skipped entirely.
+"""
+
+from datetime import datetime, timezone
+from typing import Any
+
+import pytest
+
+from central.config_models import EnrichmentConfig
+from central.enrichment.cache import EnrichmentCache
+from central.enrichment.geocoder import GeocoderEnricher, all_null_bundle
+from central.models import Event, Geo
+from central.supervisor import apply_enrichment, build_enrichers
+
+
+def _make_event(data: dict[str, Any]) -> Event:
+    return Event(
+        id="evt-1",
+        adapter="usgs_quake",
+        category="quake.event.test",
+        time=datetime(2026, 1, 1, tzinfo=timezone.utc),
+        geo=Geo(),
+        data=data,
+    )
+
+
+class _PopulatingBackend:
+    """Deterministic backend that resolves any real coords to a fixed place."""
+
+    async def reverse(self, lat: float, lon: float) -> dict[str, Any]:
+        return {**all_null_bundle(), "city": "Boise", "state": "ID"}
+
+
+@pytest.mark.asyncio
+async def test_coordless_event_with_declared_locations_gets_null_bundle(tmp_path):
+    """An event whose declared coord paths are all None still gets _enriched."""
+    cache = EnrichmentCache(tmp_path / "enrichment_cache.db")
+    enrichers = build_enrichers(EnrichmentConfig(), cache)
+    event = _make_event(
+        {"latitude": None, "longitude": None, "reason": "fallen_off_current_service"}
+    )
+    assert "_enriched" not in event.data
+
+    await apply_enrichment(event, [("latitude", "longitude")], enrichers)
+
+    assert event.data["_enriched"]["geocoder"] == all_null_bundle()
+
+
+@pytest.mark.asyncio
+async def test_event_with_coords_still_enriches_normally(tmp_path):
+    """The coord-bearing path is unchanged: the backend is consulted and its
+    resolved fields land in the bundle."""
+    cache = EnrichmentCache(tmp_path / "enrichment_cache.db")
+    enricher = GeocoderEnricher(_PopulatingBackend(), cache=cache)
+    event = _make_event({"latitude": 43.0, "longitude": -116.0})
+
+    await apply_enrichment(event, [("latitude", "longitude")], [enricher])
+
+    bundle = event.data["_enriched"]["geocoder"]
+    assert bundle["state"] == "ID"
+    assert bundle["city"] == "Boise"
+
+
+@pytest.mark.asyncio
+async def test_adapter_with_no_enrichment_locations_still_skipped(tmp_path):
+    """Adapters declaring no enrichment_locations are skipped — no _enriched."""
+    cache = EnrichmentCache(tmp_path / "enrichment_cache.db")
+    enrichers = build_enrichers(EnrichmentConfig(), cache)
+    event = _make_event({"latitude": 43.0, "longitude": -116.0})
+
+    await apply_enrichment(event, [], enrichers)
+
+    assert "_enriched" not in event.data