Ban more imports that import twisted.internet.reactor. (#6947)

pyproject.toml

@@ -398,6 +398,10 @@ ignore = [
 [tool.ruff.lint.flake8-tidy-imports]
 banned-module-level-imports = [
     "twisted.internet.reactor",
+    # indirectly imports twisted.conch.insults.helper which imports twisted.internet.reactor
+    "twisted.conch.manhole",
+    # directly imports twisted.internet.reactor
+    "twisted.protocols.ftp",
 ]
 
 [tool.ruff.lint.isort]

scrapy/core/downloader/handlers/ftp.py

@@ -37,7 +37,6 @@ from typing import TYPE_CHECKING, Any, BinaryIO
 from urllib.parse import unquote
 
 from twisted.internet.protocol import ClientCreator, Protocol
-from twisted.protocols.ftp import CommandFailed, FTPClient
 
 from scrapy.http import Response
 from scrapy.responsetypes import responsetypes
@@ -46,6 +45,7 @@ from scrapy.utils.python import to_bytes
 
 if TYPE_CHECKING:
     from twisted.internet.defer import Deferred
+    from twisted.protocols.ftp import FTPClient
     from twisted.python.failure import Failure
 
     # typing.Self requires Python 3.11
@@ -101,6 +101,7 @@ class FTPDownloadHandler:
 
     def download_request(self, request: Request, spider: Spider) -> Deferred[Response]:
         from twisted.internet import reactor
+        from twisted.protocols.ftp import FTPClient
 
         parsed_url = urlparse_cached(request)
         user = request.meta.get("ftp_user", self.default_user)
@@ -138,6 +139,8 @@ class FTPDownloadHandler:
         return respcls(url=request.url, status=200, body=body, headers=headers)  # type: ignore[arg-type]
 
     def _failed(self, result: Failure, request: Request) -> Response:
+        from twisted.protocols.ftp import CommandFailed
+
         message = result.getErrorMessage()
         if result.type == CommandFailed:
             m = _CODE_RE.search(message)

scrapy/extensions/telnet.py

@@ -12,7 +12,7 @@ import os
 import pprint
 from typing import TYPE_CHECKING, Any
 
-from twisted.conch import manhole, telnet
+from twisted.conch import telnet
 from twisted.conch.insults import insults
 from twisted.internet import protocol
 
@@ -88,6 +88,8 @@ class TelnetConsole(protocol.ServerFactory):
                 ):
                     raise ValueError("Invalid credentials")
 
+                from twisted.conch import manhole
+
                 protocol = telnet.TelnetBootstrapProtocol(
                     insults.ServerProtocol, manhole.Manhole, self._get_telnet_vars()
                 )

tests/test_downloader_handlers.py

@@ -13,7 +13,6 @@ from unittest import mock
 import pytest
 from pytest_twisted import async_yield_fixture
 from twisted.cred import checkers, credentials, portal
-from twisted.protocols.ftp import ConnectionLost, FTPFactory, FTPRealm
 from w3lib.url import path_to_file_uri
 
 from scrapy.core.downloader.handlers import DownloadHandlers
@@ -324,6 +323,8 @@ class TestFTPBase:
             (userdir / filename).write_bytes(content)
 
     def _get_factory(self, root):
+        from twisted.protocols.ftp import FTPFactory, FTPRealm
+
         realm = FTPRealm(anonymousRoot=str(root), userHome=str(root))
         p = portal.Portal(realm)
         users_checker = checkers.InMemoryUsernamePasswordDatabaseDontUse()
@@ -449,6 +450,8 @@ class TestFTP(TestFTPBase):
                 "This test produces DirtyReactorAggregateError on Windows with asyncio"
             )
 
+        from twisted.protocols.ftp import ConnectionLost
+
         meta = dict(self.req_meta)
         meta.update({"ftp_password": "invalid"})
         request = Request(url=server_url + "file.txt", meta=meta)
@@ -465,6 +468,8 @@ class TestAnonymousFTP(TestFTPBase):
             (root / filename).write_bytes(content)
 
     def _get_factory(self, tmp_path):
+        from twisted.protocols.ftp import FTPFactory, FTPRealm
+
         realm = FTPRealm(anonymousRoot=str(tmp_path))
         p = portal.Portal(realm)
         p.registerChecker(checkers.AllowAnonymousAccess(), credentials.IAnonymous)