Remove the default argument to all uses of getlist in Sanic in case none are found. Previously it defaulted to returning None. Instead return an empty list which is sensible and avoids ambiguity with return types.

sanic/cookies/request.py

@@ -149,13 +149,11 @@ class CookieRequestParameters(RequestParameters):
         except KeyError:
             return super().get(name, default)
 
-    def getlist(
-        self, name: str, default: Optional[Any] = None
-    ) -> Optional[Any]:
+    def getlist(self, name: str) -> list[Any]:
         try:
             return self._get_prefixed_cookie(name)
         except KeyError:
-            return super().getlist(name, default)
+            return super().getlist(name)
 
     def _get_prefixed_cookie(self, name: str) -> Any:
         getitem = super().__getitem__

sanic/request/parameters.py

@@ -19,15 +19,14 @@ class RequestParameters(dict):
         return super().get(name, [default])[0]
 
     def getlist(
-        self, name: str, default: Optional[Any] = None
-    ) -> Optional[Any]:
+        self, name: str
+    ) -> list[Any]:
         """Return the entire list
 
         Args:
             name (str): The name of the parameter
-            default (Optional[Any], optional): The default value. Defaults to None.
 
         Returns:
-            Optional[Any]: The entire list
+            list[Any]: The entire list of values or [] if not found
         """  # noqa: E501
-        return super().get(name, default)
+        return super().get(name) or []

sanic/response/types.py

@@ -24,6 +24,7 @@ from sanic.helpers import (
     Default,
     _default,
     has_message_body,
+    remove_entity_headers,
 )
 from sanic.http import Http
 
@@ -105,6 +106,9 @@ class BaseHTTPResponse:
         Returns:
             Iterator[Tuple[bytes, bytes]]: A list of header tuples encoded in bytes for sending
         """  # noqa: E501
+        # TODO: Make a blacklist set of header names and then filter with that
+        if self.status in (304, 412):  # Not Modified, Precondition Failed
+            self.headers = remove_entity_headers(self.headers)
         if has_message_body(self.status):
             self.headers.setdefault("content-type", self.content_type)
         # Encode headers into bytes

tests/test_cookies.py

@@ -445,10 +445,10 @@ def test_cookie_accessors(app: Sanic):
                     "four": request.cookies.get("four", "fallback"),
                 },
                 "getlist": {
-                    "one": request.cookies.getlist("one", ["fallback"]),
-                    "two": request.cookies.getlist("two", ["fallback"]),
-                    "three": request.cookies.getlist("three", ["fallback"]),
-                    "four": request.cookies.getlist("four", ["fallback"]),
+                    "one": request.cookies.getlist("one"),
+                    "two": request.cookies.getlist("two"),
+                    "three": request.cookies.getlist("three"),
+                    "four": request.cookies.getlist("four"),
                 },
                 "getattr": {
                     "one": request.cookies.one,
@@ -484,7 +484,7 @@ def test_cookie_accessors(app: Sanic):
             "one": ["1"],
             "two": ["2"],
             "three": ["3"],
-            "four": ["fallback"],
+            "four": [],
         },
         "getattr": {
             "one": "1",

tests/test_response.py

@@ -178,10 +178,6 @@ def json_app(app):
     async def unmodified_handler(request: Request):
         return json(JSON_DATA, status=304)
 
-    @app.get("/precondition")
-    async def precondition_handler(request: Request):
-        return json(JSON_DATA, status=412)
-
     @app.delete("/")
     async def delete_handler(request: Request):
         return json(None, status=204)
@@ -197,10 +193,6 @@ def test_json_response(json_app):
     assert response.text == json_dumps(JSON_DATA)
     assert response.json == JSON_DATA
 
-    request, response = json_app.test_client.get("/precondition")
-    assert response.status == 412
-    assert response.json == JSON_DATA
-
 
 def test_no_content(json_app):
     request, response = json_app.test_client.get("/no-content")