From 56b36ce7f09e64278726e329d744ebc3422f21dd Mon Sep 17 00:00:00 2001
From: Khalim Conn-Kowlessar <kconnkowlessar@gmail.com>
Date: Tue, 14 Jul 2026 21:41:04 +0000
Subject: [PATCH] =?UTF-8?q?Resolve=20the=20PasHub=20PV=20Connection=20labe?=
 =?UTF-8?q?l=20to=20the=20gov-API=20credit-gate=20int=20=F0=9F=9F=A9?=
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"Not connected to electricity meter" -> 1 (zero Appendix M credit), "Connected
to dwellings electricity meter" -> 2; the raw string fell through the credit
gate's non-int branch to True, crediting a separately-metered array (issue
#1590 bug 3, fixture 499516101839 -6.9 SAP). Harness MAE 2.571 -> 2.538;
ceiling ratcheted to 2.55.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 .../tests/test_pashub_sap_accuracy.py         |  4 ++-
 datatypes/epc/domain/mapper.py                | 28 ++++++++++++++++++-
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/backend/documents_parser/tests/test_pashub_sap_accuracy.py b/backend/documents_parser/tests/test_pashub_sap_accuracy.py
index b22c44b31..df8dd1d91 100644
--- a/backend/documents_parser/tests/test_pashub_sap_accuracy.py
+++ b/backend/documents_parser/tests/test_pashub_sap_accuracy.py
@@ -87,7 +87,9 @@ _MIN_WITHIN_HALF: float = 0.12
 # Ratcheted 2.64 -> 2.58 by #1590 bug 1 (surveyed PV arrays now reach the
 # Appendix M input): observed MAE 2.571 — 507639151843's 13.5-SAP zero-PV-credit
 # under-rate closing.
-_MAX_SAP_MAE: float = 2.58
+# Ratcheted 2.58 -> 2.55 by #1590 bug 3 (PV Connection label -> gov-API int:
+# "Not connected" no longer silently credited): observed MAE 2.538.
+_MAX_SAP_MAE: float = 2.55
 
 _KNOWN_GAP_REASON = (
     "pashub `from_site_notes` mapper does not int-code a main-heating "
diff --git a/datatypes/epc/domain/mapper.py b/datatypes/epc/domain/mapper.py
index 638042178..abc3e31e2 100644
--- a/datatypes/epc/domain/mapper.py
+++ b/datatypes/epc/domain/mapper.py
@@ -367,7 +367,7 @@ class EpcPropertyDataMapper:
                 is_dwelling_export_capable=general.dwelling_export_capable,
                 wind_turbines_terrain_type=general.terrain_type,
                 electricity_smart_meter_present=general.electricity_smart_meter,
-                pv_connection=renewables.pv_connection,
+                pv_connection=_pashub_pv_connection_code(renewables.pv_connection),
                 photovoltaic_arrays=_pashub_pv_arrays(renewables),
                 photovoltaic_supply=(
                     PhotovoltaicSupply(
@@ -6699,6 +6699,32 @@ _ELMHURST_PV_OVERSHADING_TO_RDSAP: Dict[str, int] = {
 }
 
 
+# PasHub surveyed "PV Connection" label → the gov-API int enum the calculator's
+# Appendix M credit gate keys off (`_pv_connected_to_dwelling_meter`): 1 = PV
+# present but NOT connected to the dwelling's meter (zero credit — communal /
+# separately-metered), 2 = connected (credited). The gate treats any non-int as
+# "connected", so an unresolved label silently credits PV the dwelling doesn't
+# get to count (issue #1590 bug 3).
+_PASHUB_PV_CONNECTION_TO_GOV_API: Dict[str, int] = {
+    "Not connected to electricity meter": 1,
+    "Connected to dwellings electricity meter": 2,
+}
+
+
+def _pashub_pv_connection_code(connection_label: Optional[str]) -> Optional[int]:
+    """Resolve a PasHub surveyed PV Connection label to the gov-API int enum at
+    the mapper boundary (ADR-0015). Absent stays None (no PV lodged); a
+    non-empty label the lookup does not cover strict-raises
+    `UnmappedPasHubLabel` so the gap is fixed here, never silently credited
+    downstream."""
+    if not connection_label:
+        return None
+    code = _PASHUB_PV_CONNECTION_TO_GOV_API.get(connection_label)
+    if code is None:
+        raise UnmappedPasHubLabel("PV connection", connection_label)
+    return code
+
+
 def _pashub_pv_arrays(
     renewables: PasHubRenewables,
 ) -> Optional[List[PhotovoltaicArray]]: