Fix: return (None, None) when entity doc exists but feature view was …

…never written MongoDB stores all feature views for an entity in a single document. If FV 'driver_stats' is written, an entity doc exists for driver_1. A subsequent read for FV 'pricing' (never written) was previously returning (None, {all_features: ValueProto()}) - a truthy feature dict with all-empty protos - instead of the correct (None, None) sentinel. Feast and downstream callers use (None, None) to signal entity absence. A non-None feature dict means 'entity found, values are null', which causes different behaviour in the feature retrieval pipeline. Fix: after confirming the entity doc exists, also check that the feature view key is present in doc['features']. If absent, return (None, None) rather than a dict of empty protos. Adds test_convert_raw_docs_entity_exists_but_fv_not_written to cover the multi-feature-view colocation scenario identified in code review. Signed-off-by: Casey Clements <casey.clements@mongodb.com>
feast-dev · ntkathole · Mar 10, 2026 · Jan 20, 2026 · Jan 20, 2026 · Feb 12, 2026
commit dcb9072a4694b3c532674e3de1599b92ad79721c
@@ -365,6 +365,13 @@ def _convert_raw_docs_to_proto(
                 results.append((None, None))
                 continue
 
+            # Entity document exists (written by some other feature view), but
+            # this specific feature view was never written → treat as not found.
+            fv_features = doc.get("features", {}).get(table.name)
+            if fv_features is None:
+                results.append((None, None))
+                continue
+
             ts = doc.get("event_timestamps", {}).get(table.name)
 
             row_features = {

@@ -247,6 +247,31 @@ def test_convert_raw_docs_partial_doc():
     assert feats_out["missing_feat"] == ValueProto()  # null / not-set
 
 
+def test_convert_raw_docs_entity_exists_but_fv_not_written():
+    """Entity doc exists (written by another FV) but this FV was never written → (None, None).
+
+    MongoDB stores all feature views for the same entity in one document.
+    If FV "driver_stats" was written, an entity doc exists for driver_1.
+    A subsequent read for FV "pricing" (never written) must return (None, None),
+    not a truthy dict of empty ValueProtos.
+    """
+    pricing_fv = _make_fv("price")
+    ts = datetime(2024, 1, 1, tzinfo=timezone.utc)
+    ids = [b"driver_1"]
+    # doc was created by driver_stats, pricing key is absent entirely
+    docs = {
+        b"driver_1": {
+            "features": {"driver_stats": {"acc_rate": 0.9}},
+            "event_timestamps": {"driver_stats": ts},
+        }
+    }
+
+    results = MongoDBOnlineStore._convert_raw_docs_to_proto(ids, docs, pricing_fv)
+
+    assert len(results) == 1
+    assert results[0] == (None, None)
+
+
 def test_convert_raw_docs_ordering():
     """Result order matches the ids list regardless of dict insertion order in docs."""
     fv = _make_fv("score")