[3.8] Make type hints for http parser stricter (#5267).

(cherry picked from commit a6c7f15)

Co-authored-by: Andrew Svetlov <andrew.svetlov@gmail.com>

CHANGES/5267.feature

@@ -0,0 +1 @@
+Make type hints for http parser stricter

aiohttp/client_exceptions.py

@@ -4,6 +4,7 @@
 import warnings
 from typing import TYPE_CHECKING, Any, Optional, Tuple, Union
 
+from .http_parser import RawResponseMessage
 from .typedefs import LooseHeaders
 
 try:
@@ -225,7 +226,7 @@ class ServerConnectionError(ClientConnectionError):
 class ServerDisconnectedError(ServerConnectionError):
     """Server disconnected."""
 
-    def __init__(self, message: Optional[str] = None) -> None:
+    def __init__(self, message: Union[RawResponseMessage, str, None] = None) -> None:
         if message is None:
             message = "Server disconnected"
 

aiohttp/client_proto.py

@@ -23,7 +23,7 @@ def __init__(self, loop: asyncio.AbstractEventLoop) -> None:
 
         self._should_close = False
 
-        self._payload = None
+        self._payload: Optional[StreamReader] = None
         self._skip_payload = False
         self._payload_parser = None
 
@@ -223,7 +223,7 @@ def data_received(self, data: bytes) -> None:
 
                 self._upgraded = upgraded
 
-                payload = None
+                payload: Optional[StreamReader] = None
                 for message, payload in messages:
                     if message.should_close:
                         self._should_close = True

aiohttp/http_parser.py

@@ -4,8 +4,9 @@
 import re
 import string
 import zlib
+from contextlib import suppress
 from enum import IntEnum
-from typing import Any, List, Optional, Tuple, Type, Union
+from typing import Generic, List, Optional, Tuple, Type, TypeVar, Union
 
 from multidict import CIMultiDict, CIMultiDictProxy, istr
 from yarl import URL
@@ -88,6 +89,9 @@
 )
 
 
+_MsgT = TypeVar("_MsgT", RawRequestMessage, RawResponseMessage)
+
+
 class ParseState(IntEnum):
 
     PARSE_NONE = 0
@@ -198,7 +202,7 @@ def parse_headers(
         return (CIMultiDictProxy(headers), tuple(raw_headers))
 
 
-class HttpParser(abc.ABC):
+class HttpParser(abc.ABC, Generic[_MsgT]):
     def __init__(
         self,
         protocol: Optional[BaseProtocol] = None,
@@ -239,10 +243,10 @@ def __init__(
         self._headers_parser = HeadersParser(max_line_size, max_headers, max_field_size)
 
     @abc.abstractmethod
-    def parse_message(self, lines: List[bytes]) -> Any:
+    def parse_message(self, lines: List[bytes]) -> _MsgT:
         pass
 
-    def feed_eof(self) -> Any:
+    def feed_eof(self) -> Optional[_MsgT]:
         if self._payload_parser is not None:
             self._payload_parser.feed_eof()
             self._payload_parser = None
@@ -254,10 +258,9 @@ def feed_eof(self) -> Any:
             if self._lines:
                 if self._lines[-1] != "\r\n":
                     self._lines.append(b"")
-                try:
+                with suppress(Exception):
                     return self.parse_message(self._lines)
-                except Exception:
-                    return None
+        return None
 
     def feed_data(
         self,
@@ -267,7 +270,7 @@ def feed_data(
         CONTENT_LENGTH: istr = hdrs.CONTENT_LENGTH,
         METH_CONNECT: str = hdrs.METH_CONNECT,
         SEC_WEBSOCKET_KEY1: istr = hdrs.SEC_WEBSOCKET_KEY1,
-    ) -> Tuple[List[Any], bool, bytes]:
+    ) -> Tuple[List[Tuple[_MsgT, StreamReader]], bool, bytes]:
 
         messages = []
 
@@ -346,6 +349,7 @@ def feed_data(
                             if not payload_parser.done:
                                 self._payload_parser = payload_parser
                         elif method == METH_CONNECT:
+                            assert isinstance(msg, RawRequestMessage)
                             payload = StreamReader(
                                 self.protocol,
                                 timer=self.timer,
@@ -479,13 +483,13 @@ def set_upgraded(self, val: bool) -> None:
         self._upgraded = val
 
 
-class HttpRequestParser(HttpParser):
+class HttpRequestParser(HttpParser[RawRequestMessage]):
     """Read request status line. Exception .http_exceptions.BadStatusLine
     could be raised in case of any errors in status line.
     Returns RawRequestMessage.
     """
 
-    def parse_message(self, lines: List[bytes]) -> Any:
+    def parse_message(self, lines: List[bytes]) -> RawRequestMessage:
         # request line
         line = lines[0].decode("utf-8", "surrogateescape")
         try:
@@ -542,13 +546,13 @@ def parse_message(self, lines: List[bytes]) -> Any:
         )
 
 
-class HttpResponseParser(HttpParser):
+class HttpResponseParser(HttpParser[RawResponseMessage]):
     """Read response status line and headers.
 
     BadStatusLine could be raised in case of any errors in status line.
     Returns RawResponseMessage"""
 
-    def parse_message(self, lines: List[bytes]) -> Any:
+    def parse_message(self, lines: List[bytes]) -> RawResponseMessage:
         line = lines[0].decode("utf-8", "surrogateescape")
         try:
             version, status = line.split(None, 1)

aiohttp/web_protocol.py

@@ -7,7 +7,17 @@
 from html import escape as html_escape
 from http import HTTPStatus
 from logging import Logger
-from typing import TYPE_CHECKING, Any, Awaitable, Callable, Optional, Tuple, Type, cast
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Awaitable,
+    Callable,
+    Deque,
+    Optional,
+    Tuple,
+    Type,
+    cast,
+)
 
 import yarl
 
@@ -172,7 +182,7 @@ def __init__(
         self._keepalive_timeout = keepalive_timeout
         self._lingering_time = float(lingering_time)
 
-        self._messages = deque()  # type: Any  # Python 3.5 has no typing.Deque
+        self._messages: Deque[Tuple[RawRequestMessage, StreamReader]] = deque()
         self._message_tail = b""
 
         self._waiter = None  # type: Optional[asyncio.Future[None]]