[fix]:[FL-70][删除线路时，塔杆要一起删除]

Co-authored-by: multica-agent <github@multica.ai>

api/app/api/v1/lines.py

@@ -88,15 +88,9 @@ def delete_line_endpoint(
     _: CurrentUser = Depends(require_permission("line.manage")),
     db: Session = Depends(get_db),
 ) -> dict[str, bool]:
-    deleted, tower_count = delete_line(db, line_id)
+    deleted = delete_line(db, line_id)
     if not deleted:
-        line = get_line_by_id(db, line_id)
-        if not line:
-            raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Line not found")
-        raise HTTPException(
-            status_code=status.HTTP_409_CONFLICT,
-            detail=f"Line has {tower_count} towers, delete towers first",
-        )
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Line not found")
     return {"success": True}
 
 

api/app/models/line_tower.py

@@ -12,6 +12,7 @@ from .base import utcnow
 
 if TYPE_CHECKING:
     from .line import Line
+    from .tower_profile import TowerProfile
 
 
 class LineTower(Base):
@@ -63,3 +64,11 @@ class LineTower(Base):
     update_user: Mapped[str | None] = mapped_column(String(64), index=True)
 
     line: Mapped[Line] = relationship("Line", back_populates="towers", lazy="selectin")
+    profile: Mapped[TowerProfile | None] = relationship(
+        "TowerProfile",
+        back_populates="tower",
+        lazy="selectin",
+        cascade="all, delete-orphan",
+        single_parent=True,
+        uselist=False,
+    )

api/app/models/tower_profile.py

@@ -64,4 +64,4 @@ class TowerProfile(Base):
     )
     update_user: Mapped[str | None] = mapped_column(String(64), index=True)
 
-    tower: Mapped[LineTower] = relationship("LineTower", lazy="selectin")
+    tower: Mapped[LineTower] = relationship("LineTower", back_populates="profile", lazy="selectin")

api/app/services/line_service.py

@@ -225,19 +225,15 @@ def update_line(
     )
 
 
-def delete_line(db: Session, line_id: str) -> tuple[bool, int]:
+def delete_line(db: Session, line_id: str) -> bool:
     line = get_line_by_id(db, line_id)
     if not line:
-        return False, 0
-
-    tower_count = int(db.scalar(select(func.count()).select_from(LineTower).where(LineTower.line_id == line_id)) or 0)
-    if tower_count > 0:
-        return False, tower_count
+        return False
 
     db.delete(line)
     db.commit()
     _publish_line_change("power-lines.deleted", {"action": "deleted", "line_id": line_id})
-    return True, 0
+    return True
 
 
 def list_line_towers(

api/tests/test_line_service.py

@@ -4,7 +4,7 @@ import csv
 import io
 from types import SimpleNamespace
 
-from sqlalchemy import create_engine
+from sqlalchemy import create_engine, select
 from sqlalchemy.orm import Session, sessionmaker
 
 from app.core.database import Base
@@ -73,6 +73,47 @@ def test_generate_line_code_skips_existing_code(monkeypatch) -> None:
         session.close()
 
 
+def test_delete_line_cascades_to_towers_and_profiles(monkeypatch) -> None:
+    session = _build_session()
+    try:
+        monkeypatch.setattr(line_service, "_publish_line_change", lambda *args, **kwargs: None)
+
+        line = Line(
+            code="PL-DELETE-001",
+            name="待删除线路",
+            status="enabled",
+        )
+        session.add(line)
+        session.flush()
+
+        tower = LineTower(
+            line_id=line.id,
+            seq_no=1,
+            tower_no="T-001",
+            tower_model="ZM-001",
+            tower_type="直线塔",
+        )
+        session.add(tower)
+        session.flush()
+
+        session.add(
+            TowerProfile(
+                tower_id=tower.id,
+                structure_kind="直线塔",
+            )
+        )
+        session.commit()
+
+        deleted = line_service.delete_line(session, line.id)
+
+        assert deleted is True
+        assert line_service.get_line_by_id(session, line.id) is None
+        assert session.execute(select(LineTower).where(LineTower.line_id == line.id)).scalar_one_or_none() is None
+        assert session.execute(select(TowerProfile).where(TowerProfile.tower_id == tower.id)).scalar_one_or_none() is None
+    finally:
+        session.close()
+
+
 def test_export_line_towers_to_csv_includes_legacy_professional_columns() -> None:
     session = _build_session()
     try: