Unsupported EPC schema versions are skipped with a warning, not a crash

An unrecognised schema_type used to raise ValueError and abort the whole
call; now from_api_response logs a warning and returns None so one
unmapped cert doesn't break a batch. Schema 15.0 already has a mapper
(PR #1531) so it's unaffected; only genuinely unmapped versions skip.

datatypes/epc/domain/mapper.py

@@ -2946,11 +2946,12 @@ class EpcPropertyDataMapper:
         return [EpcPropertyDataMapper._map_energy_element(e) for e in elements]
 
     @staticmethod
-    def from_api_response(data: Dict[str, Any]) -> "EpcPropertyData":
+    def from_api_response(data: Dict[str, Any]) -> Optional["EpcPropertyData"]:
         """
         Dispatch to the correct schema mapper based on schema_type.
-        Supports RdSAP-Schema-21.0.0 and RdSAP-Schema-21.0.1 only.
+        Any `schema_type` not in the allow-list below (the schemas with a
-        Raises ValueError for unsupported schemas — add cases here as needed.
+        dedicated mapper) is logged as a warning and skipped — returns None
+        rather than raising, so one unrecognised cert doesn't break a batch.
         """
 
         data = _normalize_shower_outlets(data)
@@ -3053,7 +3054,12 @@ class EpcPropertyDataMapper:
                 "mapped to EpcPropertyData, which models a single dwelling."
             )
         else:
-            raise ValueError(f"Unsupported EPC schema: {schema!r}")
+            logger.warning(
+                "Unsupported EPC schema %r — skipping this EPC (uprn=%s)",
+                schema,
+                data.get("uprn"),
+            )
+            return None
 
         return _clear_basement_flag_when_system_built(
             _with_renewable_heat_incentive(

infrastructure/epc_client/epc_client_service.py

@@ -38,7 +38,7 @@ class EpcClientService:
         except (TypeError, ValueError):
             return None
 
-    def get_by_certificate_number(self, cert_num: str) -> EpcPropertyData:
+    def get_by_certificate_number(self, cert_num: str) -> Optional[EpcPropertyData]:
         raw = call_with_retry(lambda: self._fetch_certificate(cert_num))
         return EpcPropertyDataMapper.from_api_response(raw)
 

tests/infrastructure/epc_client/test_mapper_dispatcher.py

@@ -1,5 +1,3 @@
-import pytest
-
 from datatypes.epc.domain.mapper import EpcPropertyDataMapper
 from datatypes.epc.domain.epc_property_data import EpcPropertyData
 
@@ -23,9 +21,13 @@ def test_from_api_response_rdsap_21_0_1(rdsap_21_0_1_cert):
 
 
 # ---------------------------------------------------------------------------
-# Test 3: unknown schema_type → ValueError
+# Test 3: unknown schema_type → logged warning, None returned (not raised)
 # ---------------------------------------------------------------------------
 
-def test_from_api_response_unknown_schema_raises():
+def test_from_api_response_unknown_schema_returns_none(caplog):
-    with pytest.raises(ValueError, match="Unsupported EPC schema"):
+    with caplog.at_level("WARNING"):
-        EpcPropertyDataMapper.from_api_response({"schema_type": "RdSAP-Schema-99.0.0"})
+        result = EpcPropertyDataMapper.from_api_response(
+            {"schema_type": "RdSAP-Schema-99.0.0"}
+        )
+    assert result is None
+    assert "RdSAP-Schema-99.0.0" in caplog.text