Rename SapEnergySource.mains_gas to gas_connection_available 🟩

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

domain/epc/property_overlays/main_fuel_overlay.py

@@ -32,8 +32,8 @@ _FUEL_CODES: dict[str, int] = {
 }
 
 # A "mains gas" main fuel asserts the dwelling has a mains-gas connection, so the
-# overlay must also flip `sap_energy_source.mains_gas` — not just the fuel code.
-# Without it the effective EPC says "fuel = mains gas" while `mains_gas` stays
+# overlay must also flip `sap_energy_source.gas_connection_available` — not just the fuel code.
+# Without it the effective EPC says "fuel = mains gas" while `gas_connection_available` stays
 # False, which (a) gates out the gas-boiler-upgrade Measure and (b) makes the
 # heating Generator read the dwelling as off-gas and wrongly offer HHRSH storage
 # (property 728513). Only the **private** mains-gas connection (code 26) sets it;
@@ -51,7 +51,7 @@ def fuel_overlay_for(
     code = _FUEL_CODES.get(main_fuel_value)
     if code is None:
         return None
-    mains_gas = True if main_fuel_value in _MAINS_GAS_FUEL_VALUES else None
+    gas_connection_available = True if main_fuel_value in _MAINS_GAS_FUEL_VALUES else None
     return EpcSimulation(
-        heating=HeatingOverlay(main_fuel_type=code, gas_connection_available=mains_gas)
+        heating=HeatingOverlay(main_fuel_type=code, gas_connection_available=gas_connection_available)
     )

domain/modelling/scoring/overlay_applicator.py

@@ -149,7 +149,7 @@ _SAP_HEATING_FIELDS: tuple[str, ...] = (
     "cylinder_thermostat",
     "immersion_heating_type",
 )
-_ENERGY_SOURCE_FIELDS: tuple[str, ...] = ("meter_type", "mains_gas")
+_ENERGY_SOURCE_FIELDS: tuple[str, ...] = ("meter_type", "gas_connection_available")
 
 
 def _is_off_peak_meter(meter_type: object) -> bool:

domain/modelling/simulation.py

@@ -154,7 +154,7 @@ class HeatingOverlay:
       (`water_heating_*`, cylinder size + insulation);
     - the top-level `EpcPropertyData` — `has_hot_water_cylinder`;
     - ``sap_energy_source`` — `meter_type` (an off-peak tariff for storage) and
-      `mains_gas` (cleared when the dwelling goes all-electric).
+      `gas_connection_available` (cleared when the dwelling goes all-electric).
 
     The values are **absolute target states**, not deltas (the bundle replaces
     the system regardless of the before). A `None` field means "leave the

domain/sap10_ml/tests/_fixtures.py

@@ -276,7 +276,7 @@ def make_minimal_sap10_epc(
     photovoltaic_arrays: Optional[list[PhotovoltaicArray]] = None,
     photovoltaic_supply_percent_roof_area: Optional[int] = None,
     pv_connection: Optional[int] = None,
-    mains_gas: bool = True,
+    gas_connection_available: bool = True,
     electricity_smart_meter_present: bool = False,
     gas_smart_meter_present: bool = False,
     is_dwelling_export_capable: bool = False,
@@ -319,7 +319,7 @@ def make_minimal_sap10_epc(
             list(sap_roof_windows) if sap_roof_windows is not None else None
         ),
         sap_energy_source=SapEnergySource(
-            gas_connection_available=mains_gas,
+            gas_connection_available=gas_connection_available,
             meter_type="Single",
             pv_connection=pv_connection,
             pv_battery_count=pv_battery_count,

domain/sap10_ml/tests/test_transform.py

@@ -1020,7 +1020,7 @@ def test_to_row_extracts_energy_source_booleans() -> None:
     # Arrange — gas + electricity smart meters, export capable
     epc = make_minimal_sap10_epc(
         energy_rating_current=82,
-        mains_gas=True,
+        gas_connection_available=True,
         electricity_smart_meter_present=True,
         gas_smart_meter_present=True,
         is_dwelling_export_capable=True,

tests/domain/epc/test_main_fuel_overlay.py

@@ -80,8 +80,8 @@ def test_community_mains_gas_is_a_distinct_fuel_code() -> None:
 
 def test_mains_gas_fuel_sets_the_mains_gas_connection_flag() -> None:
     # A "mains gas" fuel means the dwelling has a mains-gas connection, so the
-    # overlay must set sap_energy_source.mains_gas too — not only the fuel code.
-    # Without it the effective EPC says "fuel = mains gas" yet mains_gas=False,
+    # overlay must set sap_energy_source.gas_connection_available too — not only the fuel code.
+    # Without it the effective EPC says "fuel = mains gas" yet gas_connection_available=False,
     # which suppresses the gas-boiler-upgrade path and wrongly offers HHRSH
     # storage (the off-gas path). (Property 728513.)
     simulation = fuel_overlay_for("mains gas", 0)

tests/domain/modelling/test_heating_recommendation.py

@@ -190,9 +190,9 @@ def test_gas_boiler_house_yields_an_ashp_bundle() -> None:
         cylinder_insulation_type=1,
         cylinder_insulation_thickness_mm=50,
         cylinder_thermostat="Y",
-        gas_connection_availableater_cylinder=True,
+        has_hot_water_cylinder=True,
         meter_type="Single",
-        mains_gas=False,
+        gas_connection_available=False,
     )
 
 

tests/domain/modelling/test_overlay_applicator.py

@@ -336,11 +336,11 @@ def test_apply_folds_a_heating_overlay_across_all_five_locations() -> None:
             cylinder_insulation_thickness_mm=120,
             has_hot_water_cylinder=True,
             meter_type="18 Hour",
-            mains_gas=False,
+            gas_connection_available=False,
         )
     )
 
-    # Actgas_connection_available
+    # Act
     result: EpcPropertyData = apply_simulations(baseline, [simulation])
 
     # Assert — every targeted field routed to its home object.
@@ -413,11 +413,11 @@ def test_baseline_heating_is_not_mutated_by_a_heating_overlay() -> None:
                     main_heating_control=2404,
                     water_heating_code=903,
                     has_hot_water_cylinder=True,
-                    mains_gas=False,
+                    gas_connection_available=False,
                 )
             )
         ],
-    )gas_connection_available
+    )
 
     # Assert — the baseline's heating is untouched.
     assert baseline.sap_heating.main_heating_details[0].main_fuel_type == original_fuel