fix(IT): drop 6 duplicate pairs flagged by remap (#1349 follow-up)

bin/scripts/fixes/italy_dedup_flagged_pairs.py

@@ -0,0 +1,118 @@
+#!/usr/bin/env python3
+"""Drop the legacy half of the 6 unambiguous duplicate pairs flagged by the
+issue #1349 city remap.  Two ambiguous pairs (Sermide/Felonica and
+Corteolona/Genzone) are intentionally left for maintainer review — neither
+of their records carries the modern ISTAT-canonical merged name.
+
+Mapping (id_to_drop -> reason):
+  58976  'Pozzaglio'             -> kept 'Pozzaglio ed Uniti' (id 58977, ISTAT canonical, Q42226)
+  139523 'Limite'                -> kept 'Capraia e Limite'   (id 136799, ISTAT canonical, Q82639)
+  140714 'Napoli'                -> kept 'Naples'             (id 140713, English name = repo convention)
+  139215 'Inverno'               -> kept 'Inverno e Monteleone' (id 139216, ISTAT canonical, Q39917)
+  61530  'Trinità d\\'Agultu'    -> kept 'Trinità d\\'Agultu e Vignola' (id 61531, ISTAT canonical, Q341096)
+  61329  'Torino'                -> kept 'Turin'              (id 61575, English name = repo convention)
+
+Idempotent: re-running on already-deduplicated data produces 0 changes.
+
+Usage:
+    python3 bin/scripts/fixes/italy_dedup_flagged_pairs.py [--dry-run]
+"""
+
+from __future__ import annotations
+
+import argparse
+import json
+import sys
+from pathlib import Path
+from typing import List, Optional
+
+REPO_ROOT = Path(__file__).resolve().parents[3]
+CITIES_JSON = REPO_ROOT / "contributions/cities/IT.json"
+
+# id -> (city name, kept-id, kept-name, reason)
+DROP = {
+    58976:  ("Pozzaglio",            58977,  "Pozzaglio ed Uniti",          "ISTAT canonical merged comune"),
+    139523: ("Limite",                136799, "Capraia e Limite",            "ISTAT canonical merged comune"),
+    140714: ("Napoli",                140713, "Naples",                      "Italian-name duplicate of English-named record"),
+    139215: ("Inverno",               139216, "Inverno e Monteleone",        "ISTAT canonical merged comune"),
+    61530:  ("Trinità d'Agultu",      61531,  "Trinità d'Agultu e Vignola",  "ISTAT canonical merged comune"),
+    61329:  ("Torino",                61575,  "Turin",                       "Italian-name duplicate of English-named record"),
+}
+
+
+def main(argv: Optional[List[str]] = None) -> int:
+    parser = argparse.ArgumentParser(description=__doc__.split("\n", 1)[0])
+    parser.add_argument("--dry-run", action="store_true")
+    args = parser.parse_args(argv)
+
+    cities = json.loads(CITIES_JSON.read_text(encoding="utf-8"))
+    by_id = {c["id"]: c for c in cities}
+
+    # Verify preconditions: every drop target must exist with the expected name,
+    # and every keep target must exist with the expected name.  Refuse to mutate
+    # otherwise — these are irreversible deletions, no silent failures.
+    errors: List[str] = []
+    for drop_id, (drop_name, keep_id, keep_name, _) in DROP.items():
+        d = by_id.get(drop_id)
+        k = by_id.get(keep_id)
+        if d is None:
+            # Missing drop target = already deduped; treat as idempotent skip later.
+            continue
+        if d.get("name") != drop_name:
+            errors.append(f"id={drop_id} expected name={drop_name!r}, found {d.get('name')!r}")
+        if k is None:
+            errors.append(f"keep target id={keep_id} (would-be parent of dropped id={drop_id}) is missing")
+        elif k.get("name") != keep_name:
+            errors.append(f"keep target id={keep_id} expected name={keep_name!r}, found {k.get('name')!r}")
+    if errors:
+        print("Preconditions failed; refusing to mutate IT.json:", file=sys.stderr)
+        for e in errors:
+            print(f"  - {e}", file=sys.stderr)
+        return 2
+
+    dropped: List[dict] = []
+    skipped_already_gone: List[int] = []
+    new_cities: List[dict] = []
+    for c in cities:
+        if c["id"] in DROP:
+            dropped.append(
+                {
+                    "id": c["id"],
+                    "name": c["name"],
+                    "kept_id": DROP[c["id"]][1],
+                    "kept_name": DROP[c["id"]][2],
+                    "reason": DROP[c["id"]][3],
+                }
+            )
+        else:
+            new_cities.append(c)
+
+    for drop_id in DROP:
+        if drop_id not in by_id:
+            skipped_already_gone.append(drop_id)
+
+    print(f"Input cities:        {len(cities)}")
+    print(f"Dropped this run:    {len(dropped)}")
+    print(f"Already gone (idempotent skip): {len(skipped_already_gone)}")
+    print(f"Output cities:       {len(new_cities)}")
+    print()
+    print("Drops:")
+    for d in dropped:
+        print(f"  id={d['id']:7} {d['name']!r:35} -> kept id={d['kept_id']} ({d['kept_name']!r}) [{d['reason']}]")
+
+    if args.dry_run:
+        print("\n--dry-run: IT.json not modified.")
+        return 0
+
+    if not dropped:
+        print("\nNothing to drop; IT.json untouched.")
+        return 0
+
+    text = json.dumps(new_cities, ensure_ascii=False, indent=2)
+    CITIES_JSON.write_text(text, encoding="utf-8")
+    print(f"\nWrote {len(new_cities)} cities to {CITIES_JSON.relative_to(REPO_ROOT)}")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())