Legacy property columns no longer resolve type or built form 🟩

ADR-0056 amended: override and EPC own type/form facts; a property with
neither is Unknown whatever the legacy columns say. Mirror columns removed.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

backend/app/modelling/property_filters.py

@@ -52,12 +52,12 @@ class _ComponentResolution:
     """How one filterable component (property_type / built_form) resolves at
     each ADR-0056 precedence level: which override row names it, how its RdSAP
     numeric codes map (text labels pass through as-is), and which columns hold
-    it on the EPC and the legacy property row."""
+    it on the EPC. The legacy property.property_type / built_form columns are
+    NOT consulted (ADR-0056 amendment — overrides own those facts)."""
 
     override_component: str
     codes: dict[str, str]
     epc_columns: tuple[str, ...]
-    legacy_column: str
 
 
 _PROPERTY_TYPE = _ComponentResolution(
@@ -71,7 +71,6 @@ _PROPERTY_TYPE = _ComponentResolution(
     },
     # A cert without the property_type column falls back to its dwelling_type.
     epc_columns=("property_type", "dwelling_type"),
-    legacy_column="property_type",
 )
 
 _BUILT_FORM = _ComponentResolution(
@@ -85,7 +84,6 @@ _BUILT_FORM = _ComponentResolution(
         "6": "Enclosed Mid-Terrace",
     },
     epc_columns=("built_form",),
-    legacy_column="built_form",
 )
 
 
@@ -94,12 +92,12 @@ def resolve_filtered_property_ids(
 ) -> list[FilteredProperty]:
     """Resolve *filters* against *portfolio_id* per ADR-0056: base set is the
     portfolio's rows with ``marked_for_deletion = false``; property_type /
-    built_form resolve override → lodged EPC → predicted EPC → legacy columns
-    → "Unknown". Filters AND-combine; an absent key is unconstrained."""
+    built_form resolve override → lodged EPC → predicted EPC → "Unknown".
+    Filters AND-combine; an absent key is unconstrained."""
     # IS NOT TRUE rather than = false: the FE schema defaults the flag, but a
     # NULL must never silently exclude a property.
     base_sql = (
-        "SELECT id, postcode, property_type, built_form FROM property"
+        "SELECT id, postcode FROM property"
         " WHERE portfolio_id = :portfolio_id"
         " AND marked_for_deletion IS NOT TRUE"
     )
@@ -109,14 +107,7 @@ def resolve_filtered_property_ids(
         params["postcodes"] = filters.postcodes
     base_sql += " ORDER BY id"
     candidates = [
-        _Candidate(
-            property_id=int(row[0]),
-            postcode=row[1],
-            legacy_values={
-                _PROPERTY_TYPE.legacy_column: row[2],
-                _BUILT_FORM.legacy_column: row[3],
-            },
-        )
+        _Candidate(property_id=int(row[0]), postcode=row[1])
         for row in session.connection().execute(text(base_sql), params)
     ]
 
@@ -142,7 +133,6 @@ def resolve_filtered_property_ids(
 class _Candidate:
     property_id: int
     postcode: Optional[str]
-    legacy_values: dict[str, Optional[str]]
 
 
 def _resolved_component_values(
@@ -150,7 +140,7 @@ def _resolved_component_values(
 ) -> dict[int, str]:
     """Each candidate's effective value for *component* per the ADR-0056
     precedence: override (building_part 0) → lodged EPC → predicted EPC →
-    legacy column → "Unknown"."""
+    "Unknown"."""
     property_ids = [c.property_id for c in candidates]
 
     override_rows = session.connection().execute(
@@ -186,7 +176,6 @@ def _resolved_component_values(
             by_override.get(c.property_id)
             or by_epc_source["lodged"].get(c.property_id)
             or by_epc_source["predicted"].get(c.property_id)
-            or c.legacy_values.get(component.legacy_column)
             or _UNKNOWN
         )
         for c in candidates

docs/adr/0056-modelling-run-filter-resolution-is-a-shared-contract-with-the-app-preview.md

@@ -40,9 +40,7 @@ lands in both codebases and amends this ADR.
       built_form: 1=Detached, 2=Semi-Detached, 3=End-Terrace, 4=Mid-Terrace,
       5=Enclosed End-Terrace, 6=Enclosed Mid-Terrace. Text passes through
       as-is;
-   3. else the legacy `property.property_type` / `property.built_form`
-      columns;
-   4. else **"Unknown"** — a selectable filter value meaning exactly this
+   3. else **"Unknown"** — a selectable filter value meaning exactly this
       bucket (no resolvable value at any level).
 4. An absent filter key is unconstrained; present keys combine with **AND**.
 
@@ -57,3 +55,11 @@ lands in both codebases and amends this ADR.
 - Drift risk is accepted and mitigated by this document; a cross-repo
   contract test (same fixture set, both implementations) is the natural
   follow-on if drift ever bites.
+
+## Amendment (2026-07-08): the legacy property columns are not consulted
+
+The original rule fell back to `property.property_type` / `property.built_form`
+before "Unknown". Those columns are legacy: the override layer owns
+user-supplied type/form facts, so a property with no override and no EPC is
+**"Unknown"** whatever the legacy columns say. The app's preview must apply
+the same amendment.

infrastructure/postgres/property_table.py

@@ -57,10 +57,7 @@ class PropertyRow(SQLModel, table=True):
     has_recommendations: Optional[bool] = Field(default=None)
     updated_at: Optional[datetime] = Field(default=None)
 
-    # Columns the Modelling Run filter resolution reads (ADR-0056): the base-set
-    # exclusion flag and the legacy type/form columns (the last resort before
-    # "Unknown" in the resolution precedence). NOT NULL / defaulted in the FE
-    # schema; nullable mirrors are safe — prod enforces the real constraints.
+    # The Modelling Run filter resolution's base-set exclusion flag (ADR-0056).
+    # The legacy property_type / built_form columns are deliberately NOT
+    # mirrored: overrides and EPCs own those facts (ADR-0056 amendment).
     marked_for_deletion: Optional[bool] = Field(default=None)
-    property_type: Optional[str] = Field(default=None)
-    built_form: Optional[str] = Field(default=None)