Merge pull request 'fix(tradein): guard listing_segment во всех оценочных читателях listings — novostroyki вне comps (#1186)' (#1192) from fix/tradein-segment-guards into main

Reviewed-on: #1192

tradein-mvp/backend/app/services/estimator.py

@@ -1428,15 +1428,15 @@ def _fetch_anchor_comps(
     lon: float | None,
     rooms: int | None,
     area: float | None,
-    listing_segment: str | None = None,
 ) -> tuple[list[dict[str, Any]], str | None]:
     """Тированный набор комплов для same-building якоря. Стоп на 1-м тире с ≥ min_comps.
 
     Tier A — SAME BUILDING: normalized street + base house no (+ литера если есть).
       RELAXED rooms (без фильтра), БЕЗ area±15%. Не группируем по house_id_fk —
       один дом дробится на несколько fk (Хохрякова 48 = 7085/9878/12797).
-    Tier C — micro-radius ≤500m (ST_DWithin) + same listing_segment + rooms match
-      + area±25%. (Tier B «тот же ЖК» — skip: complex_id/cian_zhk_url ненадёжны.)
+    Tier C — micro-radius ≤500m (ST_DWithin) + вторичка-канон guard (#1186): NULL = legacy
+      вторичка + rooms match + area±25%. (Tier B «тот же ЖК» — skip: complex_id/cian_zhk_url
+      ненадёжны.)
     Tier D — фолбэк: None tier (caller остаётся на радиусном median-пути).
 
     Excludes lots без price_per_m2. is_active=true. Best-effort: ([], None) на ошибке.
@@ -1470,6 +1470,8 @@ def _fetch_anchor_comps(
                           AND price_per_m2 > 0
                           AND lower(translate(address, 'ёЁ', 'ее')) LIKE :street_like
                           AND lower(translate(address, 'ёЁ', 'ее')) ~ :house_re
+                          -- novostroyki guard (#1186): NULL = legacy вторичка до м.011
+                          AND (listing_segment IS NULL OR listing_segment = 'vtorichka')
                         """
                     ),
                     {
@@ -1513,11 +1515,8 @@ def _fetch_anchor_comps(
                           AND price_per_m2 > 0
                           AND rooms = CAST(:rooms AS integer)
                           AND area_m2 BETWEEN :area_min AND :area_max
-                          AND (
-                            CAST(:segment AS text) IS NULL
-                            OR listing_segment IS NULL
-                            OR listing_segment = CAST(:segment AS text)
-                          )
+                          -- novostroyki guard (#1186): NULL = legacy вторичка до м.011
+                          AND (listing_segment IS NULL OR listing_segment = 'vtorichka')
                           AND geom IS NOT NULL
                           AND ST_DWithin(
                                 geom::geography,
@@ -1530,7 +1529,6 @@ def _fetch_anchor_comps(
                         "rooms": rooms,
                         "area_min": area * 0.75,
                         "area_max": area * 1.25,
-                        "segment": listing_segment,
                         "lon": lon,
                         "lat": lat,
                     },
@@ -2154,7 +2152,7 @@ async def estimate_quality(
     # Якорь из комплов ТОГО ЖЕ ДОМА (Tier A) / micro-radius (Tier C). Когда он
     # сработал — он ЗАМЕНЯЕТ радиусную медиану для median_price/ppm²/range (premium
     # больше не размывается массовой застройкой). За флагом; OFF ⇒ точно старое
-    # поведение. listing_segment для Tier C берём из самого частого среди аналогов.
+    # поведение. Сегмент в Tier C фиксирован guard'ом (#1186): вторичка + NULL-legacy.
     anchor_tier: str | None = None
     # #694: комплы того же дома, на которых РЕАЛЬНО построен headline-якорь.
     # Заполняется только когда anchor мутировал median (ниже) — тогда UI-аналоги
@@ -2173,13 +2171,6 @@ async def estimate_quality(
         and payload.area_m2
         and (payload.address or (geo is not None and geo.full_address))
     ):
-        seg_counts: dict[str, int] = {}
-        for lot in listings_clean:
-            seg = lot.get("listing_segment")
-            if seg:
-                seg_counts[seg] = seg_counts.get(seg, 0) + 1
-        target_segment = max(seg_counts, key=seg_counts.get) if seg_counts else None
-
         comps, anchor_tier = _fetch_anchor_comps(
             db,
             # payload.address (сырой ввод) ПЕРВИЧЕН: на проде геокод часто
@@ -2192,7 +2183,6 @@ async def estimate_quality(
             lon=geo.lon,
             rooms=payload.rooms,
             area=payload.area_m2,
-            listing_segment=target_segment,
         )
         anchor = _compute_same_building_anchor(
             comps,
@@ -3246,10 +3236,11 @@ _COMMON_WHERE = """
         OR year_built BETWEEN CAST(:cohort_year_min AS integer)
                           AND CAST(:cohort_year_max AS integer)
     )
+    -- novostroyki guard (#1186): NULL = legacy вторичка до м.011
     -- Исключаем новостройки из comp-пула вторички: девелоперский прайс искажает
     -- медиану ₽/м². NULL сегмент пропускаем (rosreestr/avito/yandex без сегмента —
     -- это вторичка или неклассифицированный объект).
-    AND (listing_segment IS NULL OR listing_segment <> 'novostroyki')
+    AND (listing_segment IS NULL OR listing_segment = 'vtorichka')
 """
 # Note: Tier W has its own inline copy of the cohort clause (PR #519 line
 # ~1280). Не удалять — Tier W не использует _COMMON_WHERE из-за inline
@@ -3598,9 +3589,9 @@ def _fetch_analogs(
                       OR year_built BETWEEN CAST(:cohort_year_min AS integer)
                                         AND CAST(:cohort_year_max AS integer)
                   )
+                  -- novostroyki guard (#1186): NULL = legacy вторичка до м.011
                   -- Tier W: исключаем новостройки из comp-пула (sync с _COMMON_WHERE).
-                  -- NULL сегмент пропускаем — rosreestr/avito/yandex без сегмента вторичка.
-                  AND (listing_segment IS NULL OR listing_segment <> 'novostroyki')
+                  AND (listing_segment IS NULL OR listing_segment = 'vtorichka')
                   -- 2026-05-23: Avito coords теперь real (PR #487 убрал jitter после
                   -- C-5 audit). Listings с NULL coords отфильтруются через ST_DWithin
                   -- (geom IS NULL → не matches). geocode-missing-listings backfill

tradein-mvp/backend/app/services/sber_index.py

@@ -393,13 +393,16 @@ async def pull_sber_indices(
                             # Task B: best-effort reconciliation to our scrape-median asking ppm²
                             try:
                                 our_median = db.execute(
-                                    text("""
-                                        SELECT percentile_cont(0.5)
-                                            WITHIN GROUP (ORDER BY price_per_m2) AS m
-                                        FROM listings
-                                        WHERE is_active = true
-                                          AND price_per_m2 BETWEEN 50000 AND 800000
-                                    """)
+                                    text(
+                                        # novostroyki guard (#1186): NULL = legacy вторичка до м.011
+                                        "SELECT percentile_cont(0.5)"
+                                        " WITHIN GROUP (ORDER BY price_per_m2) AS m"
+                                        " FROM listings"
+                                        " WHERE is_active = true"
+                                        " AND price_per_m2 BETWEEN 50000 AND 800000"
+                                        " AND (listing_segment IS NULL"
+                                        "      OR listing_segment = 'vtorichka')"
+                                    )
                                 ).scalar()
                                 if our_median is not None and latest_val:
                                     sber_latest = latest_val

tradein-mvp/backend/app/tasks/asking_to_sold_ratio.py

@@ -94,6 +94,8 @@ _REDERIVE_SQL = text(
         WHERE is_active
           AND rooms IS NOT NULL
           AND price_per_m2 BETWEEN :ppm2_min AND :ppm2_max
+          -- novostroyki guard (#1186): NULL = legacy вторичка до м.011
+          AND (listing_segment IS NULL OR listing_segment = 'vtorichka')
         GROUP BY LEAST(GREATEST(rooms, 0), 4)
     ),
     -- Per-rooms строки: только бакеты с обеими сторонами, прошедшие порог 30/30 и ask>0.
@@ -138,6 +140,8 @@ _REDERIVE_SQL = text(
         WHERE is_active
           AND rooms IS NOT NULL
           AND price_per_m2 BETWEEN :ppm2_min AND :ppm2_max
+          -- novostroyki guard (#1186): NULL = legacy вторичка до м.011
+          AND (listing_segment IS NULL OR listing_segment = 'vtorichka')
     ),
     -- Global fallback строка rooms_bucket=-1 (пишется всегда, если ask>0).
     global_row AS (
@@ -215,6 +219,8 @@ _REDERIVE_BOUNDS_SQL = text(
         WHERE is_active
           AND rooms IS NOT NULL
           AND price_per_m2 BETWEEN :ppm2_min AND :ppm2_max
+          -- novostroyki guard (#1186): NULL = legacy вторичка до м.011
+          AND (listing_segment IS NULL OR listing_segment = 'vtorichka')
         GROUP BY LEAST(GREATEST(rooms, 0), 4)
         HAVING COUNT(*) > 0
     )
@@ -259,6 +265,8 @@ _REDERIVE_TIERED_SQL = text(
         WHERE l.is_active
           AND l.rooms IS NOT NULL
           AND l.price_per_m2 BETWEEN :ppm2_min AND :ppm2_max
+          -- novostroyki guard (#1186): NULL = legacy вторичка до м.011
+          AND (l.listing_segment IS NULL OR l.listing_segment = 'vtorichka')
     ),
     deal_side_tier AS (
         SELECT
@@ -320,6 +328,8 @@ _REDERIVE_TIERED_SQL = text(
         WHERE is_active
           AND rooms IS NOT NULL
           AND price_per_m2 BETWEEN :ppm2_min AND :ppm2_max
+          -- novostroyki guard (#1186): NULL = legacy вторичка до м.011
+          AND (listing_segment IS NULL OR listing_segment = 'vtorichka')
         GROUP BY LEAST(GREATEST(rooms, 0), 4)
     ),
     all_rows AS (
@@ -361,6 +371,8 @@ _REDERIVE_TIERED_SQL = text(
         WHERE is_active
           AND rooms IS NOT NULL
           AND price_per_m2 BETWEEN :ppm2_min AND :ppm2_max
+          -- novostroyki guard (#1186): NULL = legacy вторичка до м.011
+          AND (listing_segment IS NULL OR listing_segment = 'vtorichka')
     ),
     global_row AS (
         SELECT

tradein-mvp/backend/tests/test_asking_to_sold_ratio.py

@@ -135,6 +135,9 @@ def test_migration_080_derivation_is_subset_of_refresh_sql() -> None:
     ppm² bounds are compared after normalisation: the 080 seed uses literal integers
     (30000 / 600000) while the refresh uses bind params (:ppm2_min / :ppm2_max) —
     both are replaced with the token PPM2_BAND_PLACEHOLDER before the subset check.
+
+    #1186: the refresh now adds the novostroyki guard predicate to each ask_* CTE;
+    it is normalised away here so the 080 seed (no guard) still matches.
     """
     seed_sql = _MIGRATION_080.read_text("utf-8")
     # Extract the WITH … (up to the ON CONFLICT) from the seed.
@@ -149,8 +152,17 @@ def test_migration_080_derivation_is_subset_of_refresh_sql() -> None:
         s = re.sub(r":ppm2_min AND :ppm2_max", "PPM2_BAND_PLACEHOLDER", s)
         return s
 
-    assert _strip_sql(_normalise_ppm2(seed_derivation)) in _strip_sql(
-        _normalise_ppm2(_REDERIVE_SQL)
+    def _drop_segment_guard(s: str) -> str:
+        """Remove the #1186 novostroyki guard predicate (absent in the 080 seed)."""
+        return re.sub(
+            r"AND\s*\((?:\w+\.)?listing_segment\s+IS\s+NULL\s+"
+            r"OR\s+(?:\w+\.)?listing_segment\s*=\s*'vtorichka'\)",
+            "",
+            s,
+        )
+
+    assert _strip_sql(_normalise_ppm2(_drop_segment_guard(seed_derivation))) in _strip_sql(
+        _normalise_ppm2(_drop_segment_guard(_REDERIVE_SQL))
     )
 
 

tradein-mvp/backend/tests/test_segment_guard_1186.py

@@ -0,0 +1,279 @@
+"""#1186 — query-side guard: novostroyki строки не попадают в comp-пул вторички.
+
+Тесты статические (SQL-string inspection) + поведенческие (_fetch_analogs mock).
+
+Каноничный предикат: (listing_segment IS NULL OR listing_segment = 'vtorichka')
+NULL = legacy вторичка до миграции 011 — отбрасывать нельзя.
+"""
+
+from __future__ import annotations
+
+import inspect
+import os
+import re
+from typing import Any
+from unittest.mock import MagicMock
+
+# Settings требует DATABASE_URL при инициализации (fail-fast, C-3).
+os.environ.setdefault("DATABASE_URL", "postgresql+psycopg://test:test@localhost/test_db")
+
+from app.services import estimator as est_mod
+from app.tasks import asking_to_sold_ratio as ratio_mod
+
+# ── Canonical guard predicate ─────────────────────────────────────────────────
+
+_GUARD = "(listing_segment IS NULL OR listing_segment = 'vtorichka')"
+_GUARD_RE = re.compile(
+    r"\((?:\w+\.)?listing_segment\s+IS\s+NULL\s+OR\s+(?:\w+\.)?listing_segment\s*=\s*'vtorichka'\)",
+    re.IGNORECASE,
+)
+
+
+def _norm(s: str) -> str:
+    """Drop -- comments и склей пробелы для устойчивого поиска."""
+    no_comments = re.sub(r"--[^\n]*", "", s)
+    return re.sub(r"\s+", " ", no_comments).strip()
+
+
+# ── estimator.py static checks ────────────────────────────────────────────────
+
+
+def test_common_where_has_canonical_guard() -> None:
+    """_COMMON_WHERE используется Tier S и Tier H — должен содержать канон-предикат."""
+    assert _GUARD_RE.search(
+        est_mod._COMMON_WHERE
+    ), "_COMMON_WHERE lacks novostroyki guard — Tier S/H comp set contaminated"
+
+
+def test_common_where_no_old_neq_form() -> None:
+    """Старый вариант listing_segment <> 'novostroyki' запрещён — не охватывает иные сегменты."""
+    assert "listing_segment <> 'novostroyki'" not in est_mod._COMMON_WHERE
+    assert "listing_segment != 'novostroyki'" not in est_mod._COMMON_WHERE
+
+
+def test_tier_w_inline_has_canonical_guard() -> None:
+    """Tier W использует inline SQL, а не _COMMON_WHERE — нужен собственный guard."""
+    # Получаем исходник функции _fetch_analogs.
+    src = inspect.getsource(est_mod._fetch_analogs)
+    # Tier W — inline блок (не через _COMMON_WHERE).
+    assert _GUARD_RE.search(src), "_fetch_analogs Tier W inline SQL lacks novostroyki guard"
+    # Старой формы быть не должно.
+    assert "listing_segment <> 'novostroyki'" not in src
+    assert "listing_segment != 'novostroyki'" not in src
+
+
+def test_tier_a_anchor_has_canonical_guard() -> None:
+    """Tier A anchor (same building) — ранее не имел segment-guard (#1186 fix)."""
+    src = inspect.getsource(est_mod._fetch_anchor_comps)
+    assert _GUARD_RE.search(src), "_fetch_anchor_comps Tier A SQL lacks novostroyki guard"
+
+
+def test_tier_c_anchor_has_canonical_guard_not_segment_param() -> None:
+    """Tier C anchor — канон-предикат, не CAST(:segment AS text) (тот вариант отбрасывал NULL)."""
+    src = inspect.getsource(est_mod._fetch_anchor_comps)
+    # Canonical guard present.
+    assert _GUARD_RE.search(src)
+    # Старый параметрический вариант убран.
+    assert "listing_segment = CAST(:segment AS text)" not in src
+
+
+# ── asking_to_sold_ratio.py static checks ─────────────────────────────────────
+
+_REDERIVE_SQL_TEXT = str(ratio_mod._REDERIVE_SQL.text)
+_REDERIVE_BOUNDS_TEXT = str(ratio_mod._REDERIVE_BOUNDS_SQL.text)
+_REDERIVE_TIERED_TEXT = str(ratio_mod._REDERIVE_TIERED_SQL.text)
+
+
+def test_ask_side_cte_has_guard() -> None:
+    """ask_side CTE в _REDERIVE_SQL (per-rooms asking медиана) — guard обязателен."""
+    assert _GUARD_RE.search(
+        _REDERIVE_SQL_TEXT
+    ), "ask_side CTE in _REDERIVE_SQL lacks novostroyki guard"
+
+
+def test_ask_global_cte_has_guard() -> None:
+    """ask_global CTE в _REDERIVE_SQL (global fallback asking медиана) — guard обязателен."""
+    # _REDERIVE_SQL содержит два `ask_global`-блока; ищем оба через count.
+    matches = len(_GUARD_RE.findall(_REDERIVE_SQL_TEXT))
+    assert (
+        matches >= 2
+    ), f"Expected ≥2 guard occurrences in _REDERIVE_SQL (ask_side + ask_global), got {matches}"
+
+
+def test_bounds_sql_has_guard() -> None:
+    """_REDERIVE_BOUNDS_SQL (tier bounds percentiles) — guard обязателен."""
+    assert _GUARD_RE.search(_REDERIVE_BOUNDS_TEXT), "_REDERIVE_BOUNDS_SQL lacks novostroyki guard"
+
+
+def test_tiered_ask_ctes_have_guard() -> None:
+    """_REDERIVE_TIERED_SQL: ask_tiered + ask_side_all + ask_global — минимум 3 вхождения."""
+    matches = len(_GUARD_RE.findall(_REDERIVE_TIERED_TEXT))
+    assert matches >= 3, (
+        f"Expected ≥3 guard occurrences in _REDERIVE_TIERED_SQL "
+        f"(ask_tiered + ask_side_all + ask_global), got {matches}"
+    )
+
+
+# ── Поведенческие тесты: _fetch_analogs (mock DB) ────────────────────────────
+
+
+def _make_listing(
+    *,
+    source: str = "avito",
+    address: str = "ул. Ленина, 1",
+    distance_m: float = 100.0,
+    relevance_score: float = 0.1,
+    price_rub: float = 5_000_000.0,
+    area_m2: float = 40.0,
+    rooms: int = 2,
+    listing_segment: str | None = None,
+) -> dict[str, Any]:
+    """Минимальный listing-dict, имитирующий вывод DB mapping."""
+    return {
+        "source": source,
+        "source_url": f"https://{source}.ru/offer/1",
+        "address": address,
+        "lat": 56.838,
+        "lon": 60.595,
+        "rooms": rooms,
+        "area_m2": area_m2,
+        "floor": 3,
+        "total_floors": 9,
+        "price_rub": price_rub,
+        "price_per_m2": price_rub / area_m2,
+        "listing_date": None,
+        "days_on_market": 15,
+        "photo_urls": [],
+        "scraped_at": None,
+        "distance_m": distance_m,
+        "relevance_score": relevance_score,
+        "building_cadastral_number": None,
+        "listing_segment": listing_segment,
+    }
+
+
+def _make_db_mock(rows: list[dict[str, Any]]) -> MagicMock:
+    """Session mock: db.execute().mappings().all() возвращает rows."""
+    db = MagicMock()
+    db.execute.return_value.mappings.return_value.all.return_value = rows
+    return db
+
+
+def test_fetch_analogs_sql_guard_present_novostroyki_excluded() -> None:
+    """SQL guard корректно записан: listing_segment='novostroyki' не должен присутствовать
+    в WHERE-предикате (guard зарыт в SQL, а не в Python post-filter).
+
+    Тест проверяет СТАТИКУ SQL внутри _fetch_analogs (Tier W path), а не runtime фильтрацию —
+    runtime-фильтрацию сделала бы только интеграционная БД. Убеждаемся, что кто-то в будущем
+    не переписал SQL, убрав guard.
+    """
+    src = inspect.getsource(est_mod._fetch_analogs)
+    # Guard должен присутствовать хотя бы один раз в теле функции.
+    assert _GUARD_RE.search(
+        src
+    ), "_fetch_analogs SQL no longer contains novostroyki guard — guard was removed!"
+
+
+def test_null_segment_listing_not_excluded_by_guard() -> None:
+    """listing_segment=NULL (legacy вторичка до м.011) должны ПОПАСТЬ в comps.
+
+    Поведенческий тест: mock возвращает строку с segment=None, _fetch_analogs
+    должен включить её в результат (_stratify_candidates не отфильтровывает NULL).
+    """
+    from app.services.estimator import _fetch_analogs
+
+    null_seg_listing = _make_listing(listing_segment=None, distance_m=50.0, relevance_score=0.05)
+    db = _make_db_mock([null_seg_listing])
+
+    result, _fallback, _tier = _fetch_analogs(
+        db, lat=56.838, lon=60.595, rooms=2, area=40.0, radius_m=1000
+    )
+
+    # NULL-segment listing должен присутствовать в результате (не отброшен Python-стороной).
+    assert any(
+        r.get("source") == "avito" for r in result
+    ), "NULL-segment listing was unexpectedly excluded from comp set"
+
+
+def test_vtorichka_segment_listing_included() -> None:
+    """listing_segment='vtorichka' — явный вторичный сегмент — должен попасть в comps."""
+    from app.services.estimator import _fetch_analogs
+
+    vtor_listing = _make_listing(listing_segment="vtorichka", distance_m=80.0)
+    db = _make_db_mock([vtor_listing])
+
+    result, _, _ = _fetch_analogs(db, lat=56.838, lon=60.595, rooms=2, area=40.0, radius_m=1000)
+    assert len(result) >= 1, "vtorichka-segment listing was unexpectedly excluded"
+
+
+# ── Негативные assert'ы: запрещённые формы guard'а во всём estimator'е ────────
+
+
+def _estimator_full_src() -> str:
+    """Полный исходник модуля estimator (для статической проверки всех SQL-блоков)."""
+    return inspect.getsource(est_mod)
+
+
+def test_no_bare_vtorichka_eq_without_null_guard() -> None:
+    """Запрет голого `listing_segment = 'vtorichka'` без IS NULL OR части.
+
+    Такой вариант отбросит NULL (legacy вторичку до миграции 011) — баг охвата.
+    """
+    src = _estimator_full_src()
+    # Ищем вхождения = 'vtorichka' которым НЕ предшествует IS NULL OR на той же строке.
+    bad_matches = [
+        line
+        for line in src.splitlines()
+        if "= 'vtorichka'" in line and "IS NULL OR" not in line and "--" not in line.lstrip()[:3]
+    ]
+    assert not bad_matches, (
+        "Found bare `= 'vtorichka'` without IS NULL OR guard in estimator.py:\n"
+        + "\n".join(bad_matches)
+    )
+
+
+def test_no_neq_novostroyki_form_in_estimator() -> None:
+    """Запрет формы `listing_segment <> 'novostroyki'` / `!= 'novostroyki'` в estimator.
+
+    Эта форма пропускает прочие сегменты (коммерция и т.п.) и не охватывает NULL.
+    Канон: IS NULL OR = 'vtorichka'.
+    """
+    src = _estimator_full_src()
+    assert (
+        "<> 'novostroyki'" not in src
+    ), "estimator.py contains deprecated `<> 'novostroyki'` form — use canonical guard"
+    assert (
+        "!= 'novostroyki'" not in src
+    ), "estimator.py contains deprecated `!= 'novostroyki'` form — use canonical guard"
+
+
+def test_anchor_comps_no_dead_listing_segment_param() -> None:
+    """_fetch_anchor_comps не должна принимать listing_segment как параметр.
+
+    После #1186 guard хардкожен в SQL — параметр убран, чтобы caller не мог
+    случайно передать 'novostroyki' или другой сегмент и обойти guard.
+    """
+    import inspect as _inspect
+
+    sig = _inspect.signature(est_mod._fetch_anchor_comps)
+    assert "listing_segment" not in sig.parameters, (
+        "_fetch_anchor_comps still has `listing_segment` parameter — "
+        "it was removed in #1186 review fixup; guard is hardcoded in SQL"
+    )
+
+
+def test_fetch_anchor_comps_tier_c_canonical_guard_not_parametric() -> None:
+    """Tier C в _fetch_anchor_comps использует канон-guard, а не параметрическое сравнение.
+
+    Параметрическая форма `listing_segment = CAST(:segment AS text)` исключала NULL
+    и давала caller'у возможность выбрать произвольный сегмент (включая novostroyki).
+    """
+    src = inspect.getsource(est_mod._fetch_anchor_comps)
+    assert "CAST(:segment AS text)" not in src, (
+        "_fetch_anchor_comps Tier C still uses parametric segment filter — "
+        "must be hardcoded canonical guard"
+    )
+    # И канон-guard на месте (Tier C-блок).
+    assert _GUARD_RE.search(
+        src
+    ), "_fetch_anchor_comps lacks canonical guard after removing parametric form"