Tighten location request validation

app/services/location.py

@@ -7,13 +7,20 @@ from app.models.location import Location
 from app.schemas.location import LocationRecordRequest
 
 
-def _parse_float_compat(value: str) -> float:
+def _parse_optional_float_compat(value: str | None) -> float:
     try:
         return float(value)
     except (TypeError, ValueError):
         return 0.0
 
 
+def _parse_required_float(value: str, field_name: str) -> float:
+    try:
+        return float(value)
+    except (TypeError, ValueError) as exc:
+        raise ValueError(f"Invalid numeric value for {field_name}") from exc
+
+
 def _utc_now_rfc3339() -> str:
     now = datetime.now(timezone.utc).replace(microsecond=0)
     return now.isoformat().replace("+00:00", "Z")
@@ -26,11 +33,10 @@ def record_location(session: Session, payload: LocationRecordRequest) -> None:
         .values(
             person=payload.person,
             datetime=_utc_now_rfc3339(),
-            latitude=_parse_float_compat(payload.latitude),
-            longitude=_parse_float_compat(payload.longitude),
-            altitude=_parse_float_compat(payload.altitude),
+            latitude=_parse_required_float(payload.latitude, "latitude"),
+            longitude=_parse_required_float(payload.longitude, "longitude"),
+            altitude=_parse_optional_float_compat(payload.altitude),
         )
     )
     session.execute(stmt)
     session.commit()
-