Fix some mypy errors.

src/allmydata/web/common.py

@@ -86,6 +86,8 @@ from allmydata.util.encodingutil import (
 )
 from allmydata.util import abbreviate
 from allmydata.crypto.rsa import PrivateKey, PublicKey, create_signing_keypair_from_string
+from ..webish import TahoeLAFSRequest
+
 
 class WebError(Exception):
     def __init__(self, text, code=http.BAD_REQUEST):
@@ -723,13 +725,15 @@ def get_arg(req: IRequest, argname: str | bytes, default: Optional[T] = None, *,
 
     :return: Either bytes or tuple of bytes.
     """
+    # This is not... obvious to callers, let's say, but it does happen.
+    assert isinstance(req, TahoeLAFSRequest)
     if isinstance(argname, str):
         argname_bytes = argname.encode("utf-8")
     else:
         argname_bytes = argname
 
-    results = []
-    if argname_bytes in req.args:
+    results : list[bytes] = []
+    if req.args is not None and argname_bytes in req.args:
         results.extend(req.args[argname_bytes])
     argname_unicode = str(argname_bytes, "utf-8")
     if req.fields and argname_unicode in req.fields:

src/allmydata/web/operations.py

@@ -43,8 +43,9 @@ DAY = 24*HOUR
 
 class OphandleTable(resource.Resource, service.Service):
     """Renders /operations/%d."""
-
-    name = "operations"
+    # The type in Twisted for services is wrong in 22.10...
+    # https://github.com/twisted/twisted/issues/10135
+    name = "operations"  # type: ignore[assignment]
 
     UNCOLLECTED_HANDLE_LIFETIME = 4*DAY
     COLLECTED_HANDLE_LIFETIME = 1*DAY

src/allmydata/webish.py

@@ -242,7 +242,9 @@ class TahoeLAFSSite(Site, object):
 
 
 class WebishServer(service.MultiService):
-    name = "webish"
+    # The type in Twisted for services is wrong in 22.10...
+    # https://github.com/twisted/twisted/issues/10135
+    name = "webish"  # type: ignore[assignment]
 
     def __init__(self, client, webport, tempdir, nodeurl_path=None, staticdir=None,
                  clock=None, now_fn=time.time):