Round-trip a null Lodged Performance through persistence 🟩

The four lodged_* columns are nullable as a unit; from_domain writes them all
NULL when a predicted Property has no Lodged Performance, and to_domain
reconstructs lodged=None (lodged_sap_score is the read discriminator, mirroring
the bill block). The production lodged_* columns are FE-owned (Drizzle) and need
a companion ALTER ... DROP NOT NULL migration before the backend writes NULL.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

infrastructure/postgres/property_baseline_performance_table.py

@@ -48,12 +48,16 @@ class PropertyBaselinePerformanceModel(SQLModel, table=True):
     # Postgres won't coerce to the enum. Bind the native enums explicitly
     # (``create_type=False``: the types already exist). Values stay plain
     # strings on the domain side (``Epc(...)`` / the RebaselineReason Literal).
-    lodged_sap_score: int
-    lodged_epc_band: str = Field(
-        sa_column=Column(SAEnum(*_EPC_BANDS, name="epc", create_type=False), nullable=False)
+    # The four lodged_* columns are nullable as a unit: a predicted Property has no
+    # lodged cert, so it has no Lodged Performance (ADR-0004 amendment, #1361). They
+    # are written all-set or all-NULL; lodged_sap_score is the read discriminator.
+    lodged_sap_score: Optional[int] = None
+    lodged_epc_band: Optional[str] = Field(
+        default=None,
+        sa_column=Column(SAEnum(*_EPC_BANDS, name="epc", create_type=False), nullable=True),
     )
-    lodged_co2_emissions_t_per_yr: float
-    lodged_primary_energy_intensity_kwh_per_m2_yr: int
+    lodged_co2_emissions_t_per_yr: Optional[float] = None
+    lodged_primary_energy_intensity_kwh_per_m2_yr: Optional[int] = None
 
     effective_sap_score: int
     effective_epc_band: str = Field(
@@ -102,12 +106,17 @@ class PropertyBaselinePerformanceModel(SQLModel, table=True):
     def from_domain(
         cls, baseline: PropertyBaselinePerformance, property_id: int
     ) -> "PropertyBaselinePerformanceModel":
+        # A predicted Property has no Lodged Performance — the four lodged_* columns
+        # are all NULL then (ADR-0004 amendment, #1361).
+        lodged = baseline.lodged
         model = cls(
             property_id=property_id,
-            lodged_sap_score=baseline.lodged.sap_score,
-            lodged_epc_band=baseline.lodged.epc_band.value,
-            lodged_co2_emissions_t_per_yr=baseline.lodged.co2_emissions,
-            lodged_primary_energy_intensity_kwh_per_m2_yr=baseline.lodged.primary_energy_intensity,
+            lodged_sap_score=lodged.sap_score if lodged is not None else None,
+            lodged_epc_band=lodged.epc_band.value if lodged is not None else None,
+            lodged_co2_emissions_t_per_yr=lodged.co2_emissions if lodged is not None else None,
+            lodged_primary_energy_intensity_kwh_per_m2_yr=(
+                lodged.primary_energy_intensity if lodged is not None else None
+            ),
             effective_sap_score=baseline.effective.sap_score,
             effective_epc_band=baseline.effective.epc_band.value,
             effective_co2_emissions_t_per_yr=baseline.effective.co2_emissions,
@@ -139,12 +148,7 @@ class PropertyBaselinePerformanceModel(SQLModel, table=True):
 
     def to_domain(self) -> PropertyBaselinePerformance:
         return PropertyBaselinePerformance(
-            lodged=Performance(
-                sap_score=self.lodged_sap_score,
-                epc_band=Epc(self.lodged_epc_band),
-                co2_emissions=self.lodged_co2_emissions_t_per_yr,
-                primary_energy_intensity=self.lodged_primary_energy_intensity_kwh_per_m2_yr,
-            ),
+            lodged=self._read_lodged(),
             effective=Performance(
                 sap_score=self.effective_sap_score,
                 epc_band=Epc(self.effective_epc_band),
@@ -157,6 +161,23 @@ class PropertyBaselinePerformanceModel(SQLModel, table=True):
             bill=self._read_bill(),
         )
 
+    def _read_lodged(self) -> Optional[Performance]:
+        """The Lodged half, or None for a predicted Property whose four lodged_*
+        columns are NULL (ADR-0004 amendment, #1361). They are written as a unit
+        (`from_domain`), so lodged_sap_score is the discriminator and the other
+        three are non-null alongside it."""
+        if self.lodged_sap_score is None:
+            return None
+        assert self.lodged_epc_band is not None
+        assert self.lodged_co2_emissions_t_per_yr is not None
+        assert self.lodged_primary_energy_intensity_kwh_per_m2_yr is not None
+        return Performance(
+            sap_score=self.lodged_sap_score,
+            epc_band=Epc(self.lodged_epc_band),
+            co2_emissions=self.lodged_co2_emissions_t_per_yr,
+            primary_energy_intensity=self.lodged_primary_energy_intensity_kwh_per_m2_yr,
+        )
+
     def _read_bill(self) -> Optional[Bill]:
         """Reconstruct the Bill from the ``bill_*`` columns. The total is the
         not-None discriminator: a persisted bill always sets it, so its absence

tests/repositories/property_baseline/test_property_baseline_postgres_repository.py

@@ -83,6 +83,38 @@ def test_resaving_baseline_for_a_property_replaces_rather_than_duplicating(
     assert loaded == rerun
 
 
+def _predicted_baseline() -> PropertyBaselinePerformance:
+    """A predicted Property's baseline: no Lodged Performance (no cert to read one
+    off), only the Effective half established (ADR-0004 amendment, #1361)."""
+    return PropertyBaselinePerformance(
+        lodged=None,
+        effective=Performance(
+            sap_score=57, epc_band=Epc.D, co2_emissions=1.5, primary_energy_intensity=160
+        ),
+        rebaseline_reason="physical_state_changed",
+        space_heating_kwh=4200.0,
+        water_heating_kwh=1600.0,
+    )
+
+
+def test_predicted_baseline_round_trips_with_no_lodged_half(db_engine: Engine) -> None:
+    # Arrange — a predicted Property has no Lodged Performance; the four lodged_*
+    # columns persist as NULL and reconstruct as a None lodged half.
+    baseline = _predicted_baseline()
+    with Session(db_engine) as session:
+        PropertyBaselinePostgresRepository(session).save(baseline, property_id=13)
+        session.commit()
+
+    # Act
+    with Session(db_engine) as session:
+        loaded = PropertyBaselinePostgresRepository(session).get_for_property(13)
+
+    # Assert — the lodged half round-trips as None; the Effective half is intact.
+    assert loaded == baseline
+    assert loaded is not None
+    assert loaded.lodged is None
+
+
 def test_get_for_property_returns_none_when_absent(db_engine: Engine) -> None:
     # Arrange / Act
     with Session(db_engine) as session: